Dr. Howitt is a gynecologic and sarcoma pathologist, with academic interests in gynecologic mesenchymal tumors and morphologic and clinical correlates of molecular alterations in gynecologic neoplasia.

Clinical Focus

  • Gynecologic Disease
  • Endometrial Neoplasms
  • Fallopian Tube Neoplasms
  • Endometrial Stromal Tumors
  • Vulvar Neoplasms
  • Adenosarcoma
  • Mesonephric Ducts
  • Anatomic and Clinical Pathology

Academic Appointments

Professional Education

  • Fellowship: Brigham and Women's Hospital Dept of Pathology (2014) MA
  • Medical Education: Stanford University School of Medicine (2010) CA
  • Fellowship, Brigham and Women's Hospital, Women's and Perinatal Pathology (2014)
  • Residency: Brigham and Women's Hospital (2013) MA
  • Board Certification: American Board of Pathology, Anatomic Pathology (2013)

2023-24 Courses

Stanford Advisees

All Publications

  • A pathologist-AI collaboration framework for enhancing diagnostic accuracies and efficiencies. Nature biomedical engineering Huang, Z., Yang, E., Shen, J., Gratzinger, D., Eyerer, F., Liang, B., Nirschl, J., Bingham, D., Dussaq, A. M., Kunder, C., Rojansky, R., Gilbert, A., Chang-Graham, A. L., Howitt, B. E., Liu, Y., Ryan, E. E., Tenney, T. B., Zhang, X., Folkins, A., Fox, E. J., Montine, K. S., Montine, T. J., Zou, J. 2024


    In pathology, the deployment of artificial intelligence (AI) in clinical settings is constrained by limitations in data collection and in model transparency and interpretability. Here we describe a digital pathology framework,, that incorporates active learning and human-in-the-loop real-time feedback for the rapid creation of diverse datasets and models. We validate the effectiveness of the framework via two crossover user studies that leveraged collaboration between the AI and the pathologist, including the identification of plasma cells in endometrial biopsies and the detection of colorectal cancer metastasis in lymph nodes. In both studies, yielded considerable diagnostic performance improvements. Collaboration between clinicians and AI will aid digital pathology by enhancing accuracies and efficiencies.

    View details for DOI 10.1038/s41551-024-01223-5

    View details for PubMedID 38898173

    View details for PubMedCentralID 6345440

  • The spectrum of oestrogen receptor expression in endometrial carcinomas of no specific molecular profile. Histopathology Alafraidi, M., Hoang, L., Howitt, B. E., Longacre, T. A., McAlpine, J. N., Jamieson, A., Singh, N., Gilks, C. B., Pors, J. 2024


    Decreased oestrogen receptor (ER) expression is a marker of poor prognosis in endometrial carcinomas (EC) of no specific molecular profile (NSMP), but the optimal cut-off to separate high-risk 'low ER' versus low-risk 'high ER' expression has not been defined. Here we characterised the distribution of ER staining in a cohort of ECs.Biopsy specimens from 120 cases of NSMP EC were stained for ER and assigned an Allred score. In 66 additional cases ER staining of matched biopsy and hysterectomy were compared. Twelve of 120 tumours had an Allred score of 0-3, including three endometrioid carcinomas (EEA) (one G1, two G3), four clear cell carcinomas (CCC), two mesonephric-like adenocarcinoma (MLA) and one each of: gastric-type adenocarcinoma, carcinosarcoma and endometrial carcinoma NOS. Three had Allred scores of 4-5: two MLA and one high-grade carcinoma with yolk sac differentiation. Five had Allred scores of 6: four EEA (one G1, one G2, two G3) and one mixed clear cell and endometrioid carcinoma. The remaining 100 tumours with Allred scores ≥ 7 were all EEA (66 G1, 28 G2, five G3 and one grade unknown). Comparing the biopsy versus hysterectomy ER staining (n = 66), the results were within a single Allred score point, except two cases with strong diffuse expression in the biopsy (Allred 8) and moderate expression in the hysterectomy (Allred 5).Most NSMP ECs (> 80%) show high ER expression (Allred score ≥ 7). All non-endometrioid carcinomas and a few endometrioid carcinomas had lower ER expression (Allred score ≤ 6) or were completely negative.

    View details for DOI 10.1111/his.15241

    View details for PubMedID 38890776

  • Molecular classification of metastatic and recurrent endometrial endometrioid carcinoma: prognostic relevance among low- and high-stage tumours. Histopathology McHenry, A., Devereaux, K., Ryan, E., Chow, S., Allard, G., Ho, C. C., Suarez, C. J., Folkins, A., Yang, E., Longacre, T. A., Charu, V., Howitt, B. E. 2024


    AIMS: Molecular classification according to The Cancer Genome Atlas (TCGA) improves endometrial endometrioid carcinoma (EEC) prognostication and has specific treatment implications; however, original data were skewed towards low-grade and low-stage tumours. Herein, we molecularly classify EECs metastatic at the time of diagnosis or with subsequently documented recurrent/metastatic disease to examine correlation with clinical outcomes.METHODS: TCGA categories include POLE-mutated, microsatellite instability (MSI), p53 abnormal (p53 abnl) and no specific molecular profile (NSMP). POLE targeted sequencing at exons 9, 11, 13 and 14 and immunohistochemistry (IHC) for PMS2, MSH6 and p53 were performed to establish molecular classification.RESULTS: The distribution in our cohort of 141 EECs was similar to that generally reported in EEC, with nine POLE-mutated (6%), 45 MSI (32%), 16 p53 abnl (11%) and 71 NSMP (50%), with similar distributions between low- and high-stage cohorts. We demonstrate that when stratified by molecular subtype, disease-specific survival from the time of high-stage (stages III-IV) presentation or time of recurrence in low-stage (stages I-II) disease among metastatic and/or recurrent EEC is strongly associated with TCGA classification (high-stage P=0.02, low-stage P=0.017). Discordant molecular classification between primary and metastatic/recurrent tumours occurred in four of 105 (3.8%) patients, two related to PMS2/MSH6 IHC and two related to p53 IHC.CONCLUSIONS: We demonstrate that molecular classification is prognostically relevant not only at the time of diagnosis, but also at the time of recurrence and in the metastatic setting. Rare subclonal alterations occur and suggest a role for confirming TCGA classification in recurrent/metastatic tumours.

    View details for DOI 10.1111/his.15232

    View details for PubMedID 38859768

  • Molecular Classification Outperforms Histologic Classification in Prognostication of High-grade Endometrial Carcinomas With Undifferentiated and Sarcomatous Components. The American journal of surgical pathology Hammer, P. M., Wang, A., Vermij, L., Zdravkovic, S., Heilbroner, L., Ryan, E., Geisick, R. L., Charu, V., Longacre, T. A., Suarez, C. J., Ho, C., Jenkins, T. M., Mills, A. M., Bosse, T., Howitt, B. E. 2024


    Since the establishment of 4 molecular subgroups of endometrial carcinoma (EC), there has been significant interest in understanding molecular classification in the context of histologic features and diagnoses. ECs with undifferentiated, spindle, and/or sarcomatous components represent a diagnostically challenging subset of tumors with overlapping clinical and histologic features. We examined the clinicopathologic, morphologic, immunohistochemical, and molecular features of these tumors identified in our institutions' pathology databases using immunohistochemistry and targeted sequencing. Disease-specific survival (DSS) and progression-free survival (PFS) were analyzed using Kaplan-Meier curves and log-rank tests. One hundred sixty-two ECs were included: carcinosarcomas (UCS; n=96), dedifferentiated/undifferentiated EC (DDEC/UDEC; n=49), and grade 3 endometrioid EC with spindled growth (GR3spEEC) (n=17). All molecular subgroups were represented in all histologic subtypes and included 12 (7%) POLE-mutated (POLEmut), 43 (27%) mismatch repair-deficient (MMRd), 77 (48%) p53-abnormal (p53abn), and 30 (19%) no specific molecular profile (NSMP) tumors. However, the molecular classification (irrespective of histologic diagnosis) was a significant predictor for both DSS (P=0.008) and P≤0.0001). POLEmut EC showed an excellent prognosis with no recurrences or deaths from the disease. MMRd tumors also showed better outcomes relative to NSMP and p53abn tumors. In conclusion, molecular classification provides better prognostic information than histologic diagnosis for high-grade EC with undifferentiated and sarcomatous components. Our study strongly supports routine molecular classification of these tumors, with emphasis on molecular group, rather than histologic subtyping, in providing prognostication.

    View details for DOI 10.1097/PAS.0000000000002250

    View details for PubMedID 38780000

  • Favorable Outcome of High-grade Endometrial Stromal Sarcoma in an Adolescent. Journal of pediatric hematology/oncology Hu, B., Howitt, B. E., Cizek, S., Diver, E., Hiniker, S., Crane, J., Daldrup-Link, H., Spunt, S. L. 2024


    High-grade endometrial stromal sarcoma is a rare and aggressive soft tissue tumor characterized by YWHAE::NUTM2A/B translocations, diagnosis at a median of 50-60 years, and a poor prognosis (overall survival 30%-40%). We describe a 16-year-old patient with high-grade endometrial stromal sarcoma and regional nodal and pulmonary metastases who is a long-term survivor after grossly complete tumor resection, intensive chemotherapy, and pelvic radiotherapy. We discovered a previously undescribed YWHAE::NUTM2E translocation in the tumor. Our patient's favorable outcome suggests that intensive multimodality therapy with curative intent is appropriate for young patients with high-grade endometrial stromal sarcoma and highlights the importance of fertility preservation.

    View details for DOI 10.1097/MPH.0000000000002865

    View details for PubMedID 38691023

  • Endometrioid Endometrial RNA Index Predicts Recurrence in Stage I Patients. Clinical cancer research : an official journal of the American Association for Cancer Research Nief, C. A., Hammer, P. M., Wang, A., Charu, V., Tanweer, A., Litkouhi, B., Kidd, E., Gentles, A. J., Howitt, B. E. 2024


    PURPOSE: Risk prediction with genomic and transcriptomic data has the potential to improve patient outcomes by enabling clinicians to identify patients requiring adjuvant treatment approaches, while sparing low-risk patients from unnecessary interventions. Endometrioid endometrial carcinoma (EEC) is the most common cancer in women in developed countries, and rates of endometrial cancer are increasing.EXPERIMENTAL DESIGN: We collected a 105-patient case-control cohort of stage I EEC comprised of 45 patients who experienced recurrence less than 6 years after excision, and 60 FIGO grade matched controls without recurrence. We first utilized two RNA based, previously validated machine learning approaches, namely EcoTyper and Complexity Index in Sarcoma (CINSARC). We developed Endometrioid Endometrial RNA Index (EERI) which uses RNA expression data from 46 genes to generate a personalized risk score for each patient. EERI was trained on our 105-patient cohort and tested on a publicly available cohort of 263 stage I EEC patients.RESULTS: EERI was able to predict recurrences with 94% accuracy in the training set and 81% accuracy in the test set. In the test set, patients assigned as EERI high-risk were significantly more likely to experience recurrence (30%) than the EERI low-risk group (1%) with a hazard ratio of 9.9 (95% CI 4.1-23.8, P <0.001).CONCLUSIONS: Tumors with high-risk genetic features may require additional treatment or closer monitoring and are not readily identified using traditional clinicopathologic and molecular features. EERI performs with high sensitivity and modest specificity, which may benefit from further optimization and validation in larger independent cohorts.

    View details for DOI 10.1158/1078-0432.CCR-23-3158

    View details for PubMedID 38669067

  • Scattering-Based Light Sheet Microscopy Imaging of HPV-Associated Squamous Lesions of the Anal Canal: A Proof-of-Principle Study. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc Liang, B., Zhao, J., Kim, Y., Barry-Holson, K. Q., Bingham, D. B., Charville, G. W., Darragh, T. M., Folkins, A. K., Howitt, B. E., Kong, C. S., Longacre, T. A., McHenry, A. J., Toland, A. M., Zhang, X., Lim, K., Khan, M. J., Kang, D., Yang, E. J. 2024: 100493


    Demand for anal cancer screening is expected to rise following the recent publication of the ANCHOR trial, which showed that treatment of HSIL significantly reduces the rate of progression to anal cancer. While screening for HPV-associated squamous lesions in the cervix is well-established and effective, this is less true for other sites in the lower anogenital tract. Current anal cancer screening and prevention rely on high-resolution anoscopy (HRA) with biopsies. This procedure has a steep learning curve for providers and may cause patient discomfort. Scattering-based light-sheet microscopy (sLSM) is a novel imaging modality with the potential to mitigate these challenges through real-time, microscopic visualization of disease-susceptible tissue. Here, we report a proof-of-principle study that establishes feasibility of dysplasia detection using an sLSM device. We imaged 110 anal biopsy specimens collected prospectively at our institution's dysplasia clinic (including 30 nondysplastic, 40 LSIL and 40 HSIL specimens) and found that these optical images are highly interpretable and accurately recapitulate histopathologic features traditionally used for the diagnosis of HPV-associated squamous dysplasia. A reader study to assess diagnostic accuracy suggests that sLSM images are noninferior to H&E for the detection of anal dysplasia (sLSM accuracy = 0.87, H&E accuracy = 0.80; p = 0.066). Given these results, we believe that sLSM technology holds great potential to enhance the efficacy of anal cancer screening by allowing accurate sampling of diagnostic tissue at the time of anoscopy. While the current imaging study was performed on ex vivo biopsy specimens, we are currently developing a handheld device for in vivo imaging that will provide immediate microscopic guidance to HRA providers.

    View details for DOI 10.1016/j.modpat.2024.100493

    View details for PubMedID 38615709

  • From morphology to methylome: epigenetic studies of Müllerian mesonephric-like adenocarcinoma reveal similarities to cervical mesonephric adenocarcinoma†. The Journal of pathology Lin, L. H., Howitt, B. E., Kolin, D. L. 2024


    Mesonephric adenocarcinomas (MAs) and mesonephric-like adenocarcinomas (MLAs) are rare, aggressive neoplasms that arise in the gynecologic tract and show overlapping morphologic, immunohistochemical, and molecular features. While MAs occur in the cervix and are thought to arise from mesonephric remnants, MLAs occur in the endometrium and ovary and are believed to originate from transdifferentiation of Müllerian lesions. Both MAs and MLAs show a variety of architectural patterns, exhibit frequent expression of GATA3 by immunohistochemistry, and harbor KRAS mutations. In a recent article published in The Journal of Pathology, Kommoss and colleagues used DNA methylation profiling to extend these similarities and showed that MLAs and MAs cluster together based on their epigenetic signatures and are epigenetically distinct from other Müllerian adenocarcinomas. They also showed that MLAs and MAs harbor a high number of global copy number alterations. This study provides evidence that MLAs more closely resemble MAs than Müllerian carcinomas on an epigenetic level. As a result, the authors argue that MLA should be renamed 'mesonephric-type adenocarcinoma.' Further research is needed to establish the relationship between these two entities, their etiology, and pathogenesis. © 2024 The Pathological Society of Great Britain and Ireland.

    View details for DOI 10.1002/path.6285

    View details for PubMedID 38593211

  • The Malignant Potential of Ovarian Steroid Cell Tumors Revisited: A Multi-institutional Clinicopathologic Analysis of 115 Cases. The American journal of surgical pathology Fadare, O., Fard, E. V., Bhargava, R., Desouki, M. M., Hanley, K. Z., Ip, P. P., Li, J. J., Lu, B., Medeiros, F., Ng, J. H., Parkash, V., Pinto, A., Quick, C. M., Skala, S. L., Tokuyama, M., Turashvili, G., Wei, C. H., Xing, D., Zheng, W., Soong, T. R., Howitt, B. E. 2024


    Steroid cell tumors (SCTs) of the ovary are rare and understudied, and as such, uncertainties remain about their malignant potential, as well as clinicopathologic predictors of patient outcome. Based on a multi-institutional cohort of cases, we present findings from the largest study of SCT reported to date. Clinicopathologic data were documented on 115 cases of SCT that were assembled from 17 institutions. The median patient age was 55 years (range: 9 to 84). When measured, preoperative androgen levels were elevated in 84.2% (48/57) of patients. A total of 111 (96.5%) cases were classified as stage I (103 stage IA; 2 stage IB; 6 stage IC). The stage distribution for the remaining 4 patients was as follows: stage II (n = 1), III (n = 3; 1 IIIA, 1 IIIB, 1 IIIC). The median tumor size was 3 cm (range: 0.2 to 22). Cytologic atypia, microscopic tumor necrosis, microscopic tumor hemorrhage, and a mitotic index of >1 mitotic figure/10 high-power fields were present in 52% (60/115), 9.6% (11/115), 37% (43/115), and 19% (22/115) of cases, respectively. Of 115 patients, 7 (6.1%) recurred postexcision, 4 (3.5%) ultimately died of disease, and 10 (8.7%) either recurred, died of disease, or were advanced stage at presentation. The median duration to recurrence postresection was 33 months (range: 23 to 180). Four of the 7 recurrences were stage IA at baseline. Tumor size >4 cm, International Federation of Gynecology and Obstetrics (FIGO) stage ≥IB, tumor necrosis, and tumor hemorrhage were each significantly associated with reduced recurrence-free survival in log-rank tests and univariable Cox models, with age older than 65 years being of marginal significance (hazard ratio [HR]: 5.4, 95% CI: 1.0-30.0, P= 0.05). Multivariable analyses suggested that FIGO stage ≥IB (HR: 27.5, 95% CI: 2.6-290.5), and age older than >65 years (HR: 21.8, 95% CI: 1.6-303.9) were the only parameters that were independently associated with recurrence. Cross-section analyses showed that tumor necrosis, tumor hemorrhage, and larger tumor size were significantly associated with a FIGO stage ≥IB status, which bolstered the conclusion that they are not independent predictors of recurrence. In summary, <10% of SCTs are clinically malignant, a substantially lower frequency than has previously been reported in the literature. Clinicopathologic predictors of patient outcomes that are prospectively applicable in practice could not be definitively established. Recurrences may occur many years (up to 15 y in this study) after primary resection, even in stage IA cases.

    View details for DOI 10.1097/PAS.0000000000002201

    View details for PubMedID 38512100

  • Vulvar Cancer, Version 3.2024, NCCN Clinical Practice Guidelines in Oncology. Journal of the National Comprehensive Cancer Network : JNCCN Abu-Rustum, N. R., Yashar, C. M., Arend, R., Barber, E., Bradley, K., Brooks, R., Campos, S. M., Chino, J., Chon, H. S., Crispens, M. A., Damast, S., Fisher, C. M., Frederick, P., Gaffney, D. K., Gaillard, S., Giuntoli, R. I., Glaser, S., Holmes, J., Howitt, B. E., Kendra, K., Lea, J., Lee, N., Mantia-Smaldone, G., Mariani, A., Mutch, D., Nagel, C., Nekhlyudov, L., Podoll, M., Rodabaugh, K., Salani, R., Schorge, J., Siedel, J., Sisodia, R., Soliman, P., Ueda, S., Urban, R., Wethington, S. L., Wyse, E., Zanotti, K., McMillian, N., Espinosa, S. 2024; 22 (2): 117-135


    Vulvar cancer is annually diagnosed in an estimated 6,470 individuals and the vast majority are histologically squamous cell carcinomas. Vulvar cancer accounts for 5% to 8% of gynecologic malignancies. Known risk factors for vulvar cancer include increasing age, infection with human papillomavirus, cigarette smoking, inflammatory conditions affecting the vulva, and immunodeficiency. Most vulvar neoplasias are diagnosed at early stages. Rarer histologies exist and include melanoma, extramammary Paget's disease, Bartholin gland adenocarcinoma, verrucous carcinoma, basal cell carcinoma, and sarcoma. This manuscript discusses recommendations outlined in the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for treatments, surveillance, systemic therapy options, and gynecologic survivorship.

    View details for DOI 10.6004/jnccn.2024.0013

    View details for PubMedID 38503056

  • UCHL1 is a potential molecular indicator and therapeutic target for neuroendocrine carcinomas. Cell reports. Medicine Liu, S., Chai, T., Garcia-Marques, F., Yin, Q., Hsu, E. C., Shen, M., Shaw Toland, A. M., Bermudez, A., Hartono, A. B., Massey, C. F., Lee, C. S., Zheng, L., Baron, M., Denning, C. J., Aslan, M., Nguyen, H. M., Nolley, R., Zoubeidi, A., Das, M., Kunder, C. A., Howitt, B. E., Soh, H. T., Weissman, I. L., Liss, M. A., Chin, A. I., Brooks, J. D., Corey, E., Pitteri, S. J., Huang, J., Stoyanova, T. 2024: 101381


    Neuroendocrine carcinomas, such as neuroendocrine prostate cancer and small-cell lung cancer, commonly have a poor prognosis and limited therapeutic options. We report that ubiquitin carboxy-terminal hydrolase L1 (UCHL1), a deubiquitinating enzyme, is elevated in tissues and plasma from patients with neuroendocrine carcinomas. Loss of UCHL1 decreases tumor growth and inhibits metastasis of these malignancies. UCHL1 maintains neuroendocrine differentiation and promotes cancer progression by regulating nucleoporin, POM121, and p53. UCHL1 binds, deubiquitinates, and stabilizes POM121 to regulate POM121-associated nuclear transport of E2F1 and c-MYC. Treatment with the UCHL1 inhibitor LDN-57444 slows tumor growth and metastasis across neuroendocrine carcinomas. The combination of UCHL1 inhibitors with cisplatin, the standard of care used for neuroendocrine carcinomas, significantly delays tumor growth in pre-clinical settings. Our study reveals mechanisms of UCHL1 function in regulating the progression of neuroendocrine carcinomas and identifies UCHL1 as a therapeutic target and potential molecular indicator for diagnosing and monitoring treatment responses in these malignancies.

    View details for DOI 10.1016/j.xcrm.2023.101381

    View details for PubMedID 38244540

  • Clinical Features of SARS-CoV-2 Infection During Pregnancy and Associated Placental Pathologies INTERNATIONAL JOURNAL OF GYNECOLOGICAL PATHOLOGY Ryan, E. E., Brar, N., Allard, G., Wang, A., Winn, V. D., Folkins, A., Yang, E. J., Tan, S., Hazard, F. K., Howitt, B. E. 2024; 43 (1): 15-24


    We reviewed the clinicopathologic findings of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-exposed placentas at our institution. We identified patients diagnosed with SARS-CoV-2 during pregnancy (March-October 2020). Clinical data included gestational age at diagnosis and delivery and maternal symptoms. Hematoxylin and eosin slides were reviewed for maternal vascular malperfusion, fetal vascular malperfusion, chronic villitis, amniotic fluid infection, intervillous thrombi, fibrin deposition, and infarction. Immunohistochemistry (IHC) for coronavirus spike protein and RNA in situ hybridization (ISH) for SARS-CoV-2 was performed on a subset of blocks. A review of placentas from age-matched patients received March-October 2019 was conducted as a comparison cohort. A total of 151 patients were identified. Placentas in the 2 groups were similar in weight for gestational age and had similar rates of maternal vascular malperfusion, fetal vascular malperfusion, amniotic fluid infection, intervillous thrombi, fibrin deposition, and infarction. Chronic villitis was the only significantly different pathologic finding between cases and controls (29% of cases showed chronic villitis vs. 8% of controls, P <0.001). Overall, 146/151 (96.7%) cases were negative for IHC and 129/133 (97%) cases were negative for RNA ISH. There were 4 cases that stained positively for IHC/ISH, 2 of which showed massive perivillous fibrin deposition, inflammation, and decidual arteriopathy. Coronavirus disease 2019 (COVID-19)-positive patients were more likely to self-identify as Hispanic and more likely to have public health insurance. Our data suggests SARS-CoV-2 exposed placentas that stain positively for SARS-CoV-2 show abnormal fibrin deposition, inflammatory changes, and decidual arteriopathy. The group of patients with clinical COVID-19 are more likely to show chronic villitis. IHC and ISH evidence of viral infection is rare.

    View details for DOI 10.1097/PGP.0000000000000948

    View details for Web of Science ID 001124179400010

    View details for PubMedID 36811832

  • Specific Pathology Features Enrich Selection of Endometrial Carcinomas for POLE Testing. The American journal of surgical pathology Keyhanian, K., Han, L., Howitt, B. E., Longacre, T. 2023


    Identification of ultramutated/POLE-mutated endometrial carcinomas (POLEM ECs) has important implications given its association with better prognosis. However, POLE mutation testing is not widely available. Our objective was to evaluate POLEM ECs versus POLE wild-type (POLEWT) ECs, within a cohort of consultation cases with features suggestive of an ultramutated phenotype. Consultation cases of EC that had undergone POLE hotspot mutation testing over a 3.5-year period were included. Tumor morphology and immunohistochemistry were reviewed for both groups. Chi-square test and t test were used for statistical analysis. Of 25 consultation cases, 12 harbored a POLE mutation (48%) and 13 were wild-type (52%). Patients with POLEM ECs were younger (59 vs. 71.3 y; P=0.01). Ambiguous histomorphology (5/12 vs. 1/13; P=0.04) and the presence of more than rare bizarre nuclei (8/12 vs. 2/12; P=0.01) differed significantly between POLEM and POLEWT ECs, respectively. In the POLEM group, one case (1/12) demonstrated PMS2 loss, and one (1/12) showed subclonal MLH1/PMS2 loss. Among POLEWT ECs, 3/13 (23%) showed MLH1/PMS2 loss. p53 was subclonally overexpressed in 4/10 POLEM and 1/13 POLEWT cases (P=0.06). Mutant p53 patterns were seen in 1/10 POLEM versus 6/13 of POLEWT ECs, respectively (P=0.06). Within our cohort, the specificity of ambiguous histomorphology, bizarre nuclei, subclonal biomarker expression, and marked tumor-infiltrating lymphocytes for POLEM EC was 83%, 80%, 80%, and 71%, respectively. Where universal POLE testing is not available, these data suggest that morphologic screening (particularly ambiguous histomorphology and the presence of more than rare bizarre nuclei) can be useful for selective enrichment of ECs for POLE testing.

    View details for DOI 10.1097/PAS.0000000000002165

    View details for PubMedID 38062789

  • SMARCA4 loss irrelevant for ARID1A mutated ovarian clear cell carcinoma: A case report. Gynecologic oncology reports Wagner, S. K., Moon, A. S., Howitt, B. E., Renz, M. 2023; 50: 101305


    Clear cell carcinomas are rare and relatively chemo-insensitive ovarian cancers with a characteristic molecular pathogenesis. Alterations in ARID1A, a component of the multiprotein chromatin remodeling complex SWI/SNF, are likely early events in the development of ovarian clear cancers arising from atypical endometriosis. Insight into additional driver events and particularly mutations in the same chromatin remodeling complex is limited. Isolated loss of SMARCA4, encoding the ATPase of the SWI/SNF complex, characterizes other aggressive gynecologic cancers including small cell carcinomas of the ovary hypercalcemic type (SCCOHT), undifferentiated endometrial carcinomas (UDEC), and uterine sarcomas (SDUS). The ovarian clear cell carcinoma of a 48-year-old showed in the initial surgical specimen a subclonal loss of SMARCA4 in addition to an ARID1A mutation, i.e., two alterations in the SWI/SNF heterochromatin remodeling complex. We anticipated that the SMARCA4 loss would worsen the disease course in analogy to SCCOHT, UDEC, and SDUS. However, the disease did not accelerate. Instead, the recurrent disease showed restored SMARCA4 expression while retaining the ARID1A mutation. Combinatorial redundancy, diversity and sequence in the SWI/SNF complex assembly as well as DNA- and tissue-specificity may explain the observed irrelevance of SMARCA4 loss in the presented ARID1A mutated ovarian clear cell carcinoma.

    View details for DOI 10.1016/j.gore.2023.101305

    View details for PubMedID 38033359

    View details for PubMedCentralID PMC10685047

  • FIGO 2023 endometrial cancer staging: too much, too soon? International journal of gynecological cancer : official journal of the International Gynecological Cancer Society McCluggage, W. G., Bosse, T., Gilks, C. B., Howitt, B. E., McAlpine, J. N., Nucci, M. R., Rabban, J. T., Singh, N., Talia, K. L., Parra-Herran, C. 2023


    An updated International Federation of Gynecology and Obstetrics (FIGO) staging system for endometrial carcinoma was introduced in June 2023. The new system represents a significant departure from traditional endometrial and other gynecological carcinoma staging systems which are agnostic of parameters such as tumor type, tumor grade, lymphovascular space invasion, and molecular alterations. The updated system, which incorporates all of these 'non-anatomical' parameters, is an attempt to make staging more personalized and relevant to patient prognostication and management, and to align with the European Society of Gynaecological Oncology/European Society for Radiotherapy and Oncology/European Society of Pathology (ESGO/ESTRO/ESP) risk stratification. Herein, we present a critical review of the new staging system and discuss its advantages and disadvantages. The authors propose that the new FIGO staging system should be first appraised at a multi-institutional and global level with the input of all relevant societies (gynecology, pathology, gynecologic oncology, medical oncology, radiation oncology) to understand the impact, scope, and supporting evidence of the proposed changes. Such a process is fundamental to produce a robust system that pathologists and treating clinicians can adopt.

    View details for DOI 10.1136/ijgc-2023-004981

    View details for PubMedID 37935523

  • Aberrant nuclear β-catenin distribution does not prognosticate recurrences of endometrioid endometrial cancers - A retrospective single-institutional study. Gynecologic oncology Beshar, I., Moon, A. S., Darji, H., Liu, C., Jennings, M. T., Dorigo, O., Litkouhi, B., Diver, E. J., Karam, A. K., Howitt, B. E., Renz, M. 2023; 179: 85-90


    Aberrant β-catenin distribution has been theorized as a predictive biomarker for recurrence in early stage, low grade endometrioid endometrial cancer.This retrospective single-institution cohort study reviewed 410 patients with endometrial cancer from May 2018 to May 2022. Only endometrioid histology was included. Demographic and clinicopathological data were collected from the medical records. Univariate and multivariate logistic regressions, and sensitivity analyses for early stage, low grade and no specific molecular profile (NSMP) tumors were performed.297 patients were included for analysis. Most patients were over 60 years old, White, and with a BMI >30 and early stage low grade disease. Aberrant β-catenin distribution was found in 135 patients (45.5%) and wild type membranous β-catenin distribution in 162 (54.5%). While TP53 mutation correlated with endometrial cancer recurrence in this cohort (OR = 4.78), aberrant β-catenin distribution did not correlate in the overall population (OR = 0.75), the early stage low grade cancers (OR = 0.84), or the NSMP group (OR = 1.41) on univariate or multivariate analysis. No correlation between β-catenin distribution and local (OR = 0.61) or distant recurrences (OR = 0.90) was detected.Aberrant β-catenin distribution did not significantly correlate with recurrence in endometrioid endometrial cancer, nor in the early stage, low grade and NSMP sub-cohorts.

    View details for DOI 10.1016/j.ygyno.2023.10.025

    View details for PubMedID 37944330

  • Clinical Behavior and Molecular Landscape of Stage I p53-abnormal Low-Grade Endometrioid Endometrial Carcinomas. Clinical cancer research : an official journal of the American Association for Cancer Research Jamieson, A., Vermij, L., Kramer, C. J., Jobsen, J. J., Jürgenliemk-Schulz, I., Lutgens, L., Mens, J. W., Haverkort, M. A., Slot, A., Nout, R. A., Oosting, J., Carlson, J., Howitt, B. E., Ip, P. P., Lax, S. F., McCluggage, W. G., Singh, N., McAlpine, J. N., Creutzberg, C. L., Horeweg, N., Gilks, C. B., Bosse, T. 2023


    The clinical significance of the p53-abnormal (p53abn) molecular subtype in stage I low-grade endometrioid endometrial carcinoma (EEC) is debated. We aimed to review pathological and molecular characteristics, and outcomes of stage I low-grade p53abn EEC in a large international cohort.Previously diagnosed stage I p53abn EC (POLE-wildtype, mismatch repair-proficient) low-grade EEC from Canadian retrospective cohorts and PORTEC-1&2 trials were included. Pathology review was performed by six expert gynecologic pathologists blinded to p53-status. Immunohistochemical profiling, next generation sequencing and shallow whole genome sequencing was performed. Kaplan-Meier's method was used for survival analysis.We identified 55 stage I p53abn low-grade EEC among 3387 cases (2.5%). On pathology review, 17 cases (31%) were not diagnosed as low-grade EEC by any pathologists, whereas 26 cases (47%) were diagnosed as low-grade EEC by at least three pathologists. The immunohistochemical and molecular profile of the latter cases were consistent with low-grade EEC morphology (ER/PR positivity, patchy p16 expression, PIK3CA and PTEN mutations) but they also showed features of p53abn EC (TP53 mutations, many copy number alterations). These cases had a clinically relevant risk of disease recurrence (5-year recurrence-free survival 77%), with pelvic and/or distant recurrences observed in 12% of the patients.A subset of p53abn EC is morphologically low-grade EEC and exhibit genomic instability. Even for stage I disease, p53abn low-grade EEC are at substantial risk of disease recurrence. These findings highlight the clinical relevance of universal p53-testing, even in low-grade EEC, to identify women at increased risk of recurrence.

    View details for DOI 10.1158/1078-0432.CCR-23-1397

    View details for PubMedID 37773079

  • Does lymph node assessment change the prognostic significance of substantial LVSI and p53 status in endometrial endometrioid carcinoma? Gynecologic oncology Hui, C., Mendoza, M. G., von Eyben, R., Dorigo, O., Litkouhi, B., Renz, M., Karam, A., Hammer, P. M., Howitt, B. E., Kidd, E. 2023; 177: 150-156


    The PORTEC-2 update suggested that substantial lymphovascular space invasion (LVSI) and abnormal p53 expression (p53abnl) predict for poorer outcomes and that these patients should be treated with external beam radiation therapy (EBRT). We aim to determine if patients with these risk factors who undergo a lymph node (LN) assessment show similar outcomes.We retrospectively reviewed 126 patients with FIGO 2009 stage IA grade 3, stage IB grade 1-2, and stage IIIC (positive LN but no other stage II/III risk factors) endometrioid endometrial cancer who underwent LN assessment. Local (LR), regional recurrences (RR), and distant metastases were analyzed using competing risk methods, and overall survival (OS) was analyzed using Kaplan-Meier.Median follow-up time was 37.2 months. OS was significantly different between patients with and without p53abnl expression (16.7% versus 3.1% deceased), and between patients with and without LVSI (11.1% versus 1.5% deceased; p < 0.01 for both). The 2-year cumulative incidence of LR for patients with p53abnl versus wild type p53 and LVSI versus no LVSI was 11.1% (95% CI 0-25.6) versus 2.2% (95% CI 0-5.25; p = 0.04), and 11.4% (95% CI 2.0-20.9) versus 0%, respectively (p < 0.01). The 2-year cumulative RR in patients with LVSI versus no LVSI was 6.9% (95% CI 0-14.4) versus 0% (p = 0.05). No patients who completed pelvic RT experienced an in-field recurrence.Despite LN assessment, patients with high-intermediate risk early-stage or stage IIIC (with positive lymph nodes only but no other stage II or III risk factors) endometrial cancer with p53abnl expression and/or LVSI have worse outcomes. These patients may derive benefit from intensification with EBRT to improve local and pelvic control.

    View details for DOI 10.1016/j.ygyno.2023.09.001

    View details for PubMedID 37696217

  • Nuclear beta-Catenin Expression in the Context of Abnormal p53 Expression Indicates a Nonserous Histotype in Endometrial Carcinoma INTERNATIONAL JOURNAL OF GYNECOLOGICAL PATHOLOGY Keyhanian, K., Yang, E. J., Howitt, B. E. 2023; 42 (5): 435-442


    The interobserver reproducibility is poor for histotyping within the p53-abnormal molecular category of endometrial carcinomas (ECs); therefore, biomarkers that improve histologic classification are useful. β-catenin has been proposed to have prognostic significance in specific clinicopathologic and molecular contexts. The diagnostic utility for β-catenin expression patterns in determining the histotype of p53-abnormal ECs has not been well studied. We identified ECs molecularly classified as "p53-abnormal." The p53-abnormal classification was assigned when (1) no POLE exonuclease domain hotspot mutations identified, (2) mismatch-repair protein expression was retained, and (3) abnormal p53 expression (null or overexpression) was present. Morphology was re-reviewed and β-catenin immunohistochemistry was scored as abnormal (nuclear) or normal (membranous, non-nuclear). Eighty ECs were identified in the "p53-abnormal" category; 27 (33.75%) were uterine serous carcinomas, and 53 were of nonserous histotype: 28 uterine carcinosarcomas (35%), 16 endometrioid carcinomas (20%), 2 clear cell carcinomas (2.5%), and 7 high-grade EC with ambiguous morphology (8.75%). All 27 uterine serous carcinomas demonstrated membranous β-catenin staining. Of the 53 nonserous ECs, 11 (21%) showed abnormal β-catenin expression: 6 endometrioid carcinomas, 4 uterine carcinosarcoma, and 1 high-grade EC with ambiguous morphology. The specificity of abnormal β-catenin expression for nonserous EC is high (100%) but the sensitivity is low (21%) with positive and negative predictive values of 100% and 60%, respectively. Our data shows that abnormal β-catenin expression in the context of p53-abnormal EC is highly specific, but not sensitive, for nonserous ECs and may be of value as part of a panel in classifying high-grade EC, particularly to exclude uterine serous carcinoma when nuclear staining is present.

    View details for DOI 10.1097/PGP.0000000000000923

    View details for Web of Science ID 001048516000001

    View details for PubMedID 36731035

  • Detection of FOXL2 C134W Mutation Status by a Novel BaseScope-ISH Assay is Highly Sensitive and Specific for Adult Granulosa Cell Tumors. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc Hammer, P. M., Wang, A., Beard, C., Zdravkovic, S., Tenney, T., Liang, B., Das, I., Bremer, R., Wang, L. C., McCluggage, W. G., Stewart, C. J., Howitt, B. E. 2023: 100318


    Adult granulosa cell tumors (AGCT) are a molecularly distinct group of malignant ovarian sex cord-stromal tumors (SCST) characterized by a nearly ubiquitous c.402C>G/p.C134W mutation in FOXL2 (hereafter referred to as "C134W"). In some cases, AGCT exhibits marked morphological overlap with other SCSTs, and have an identical immunophenotype, and molecular testing may be necessary to help confirm the diagnosis. However, molecular testing is time-consuming, relatively expensive, and unavailable in many pathology laboratories. We describe the development and validation of an in situ hybridization (ISH) custom BaseScope assay for the detection of the FOXL2 C134W mutation. We evaluated 106 ovarian SCSTs, including 78 AGCT, 9 juvenile granulosa cell tumors, 18 fibromas (cellular and conventional), and 1 SCST, not otherwise specified (NOS), as well as 53 epithelial ovarian tumors (42 endometrioid carcinomas and 11 carcinosarcomas) and 1 STK11 adnexal tumor for the presence or absence of FOXL2 wild-type and FOXL2 C134W RNA expression via Basescope-ISH. Fifty-one tumors had previously undergone DNA sequencing of the FOXL2 gene. Across the entire cohort, the FOXL2 C134W probe staining was positive in 77/78 (98.7%) AGCTs. 2/81 (2.5%) non-AGCT also showed positive staining, both of which were epithelial ovarian tumors. The assay worked in tissue blocks >20 years old. There was 100% concordance between the FOXL2 sequencing and Basescope-ISH results. Overall, assessment of FOXL2 mutation status by custom Basescope-ISH demonstrated 98.7% sensitivity and 97.5% specificity for the diagnosis of AGCT. Basescope-ISH for FOXL2 C134W represents a reasonable alternative to sequencing, is quicker and less expensive, and is more easily incorporated than molecular testing into many pathology laboratories. It also has the advantage of requiring less tissue, and the neoplastic cells can be directly visualized on stained sections.

    View details for DOI 10.1016/j.modpat.2023.100318

    View details for PubMedID 37634867

  • Adjuvant radiation therapy in early-stage endometrial cancer with abnormal beta-catenin expression is associated with improved local control. Gynecologic oncology Hui, C., Mendoza, M. G., Snyder, J., Dorigo, O., Litkouhi, B., Renz, M., Karam, A., Devereaux, K., Howitt, B. E., Kidd, E. A. 2023; 174: 42-48


    Emerging data suggests that abnormal (nuclear) β-catenin expression in some settings is associated with poorer outcomes. Our study aimed to verify the significance of abnormal β-catenin expression in early-stage endometrial cancer patients and determine if adjuvant radiation therapy (RT) improves local control.We identified 213 patients with FIGO 2018 stage I-II endometrioid endometrial cancer who underwent surgery from 2009 to 2021 with β-catenin expression assessed. Vaginal, regional, and distant recurrences were analyzed using competing risk methods, and overall survival was analyzed using Kaplan-Meier.Median follow up was 53.2 months; 6.9% experienced vaginal, 8.2% regional, and 7.4% distant recurrence. For the entire cohort, abnormal β-catenin expression was significantly associated with vaginal recurrence and remained significant on multivariate analysis (p = 0.03). There were 114 patients in the no specific molecular profile (NSMP) subgroup, and abnormal β-catenin expression was present in 46.5%. In the NSMP subgroup, abnormal β-catenin expression was associated with increased rates of vaginal recurrence (p = 0.06). Abnormal β-catenin expression in the NSMP subgroup was significant on multivariate analysis for vaginal recurrence (p = 0.04). RT significantly decreased vaginal recurrences in the entire cohort in patients with abnormal β-catenin expression (0%) versus wild type expression (17.5%; p = 0.03). In the NSMP subgroup 0% of patients who received RT versus 20.9% of patients who did not receive RT experienced a vaginal recurrence (p = 0.03).Use of adjuvant RT for stage I-II NSMP endometrial cancer with abnormal β-catenin expression improved local control. RT should be considered in these patients to decrease risk of vaginal recurrences.

    View details for DOI 10.1016/j.ygyno.2023.04.018

    View details for PubMedID 37149904

  • Genome-Wide DNA Methylation Identifies Distinct Subgroups of Vulvovaginal Mesenchymal Neoplasia Neil, A., Howitt, B., Yu, J., Bennett, J., Pinto, A., Quick, C., Neville, G., Nucci, M., Chapel, D., Heilbroner, L., Wang, A., Yao, Y., Ahmann, L., Gu, W., Parra-Herran, C. ELSEVIER SCIENCE INC. 2023: S960-S961
  • Challenges in Histologic Evaluation of Ovarian Mucinous Neoplasms: A Multi-Institutional Interobserver Study Turashvili, G., Fadare, O., Gutman, D., Howitt, B., Liang, B., Murali, R., Mosunjac, M., Parkash, V., Shahi, M., Quick, C., Hanley, K. ELSEVIER SCIENCE INC. 2023: S993
  • DNA Methylation Based Classification of Rare Mesenchymal Tumors of the Uterus Identifies Novel Molecular Classes Kommoss, F., Kolin, D., Howitt, B., Parra-Herran, C., Nucci, M., Dickson, B., Lee, J., Agaimy, A., Von Deimling, A., Lee, C. ELSEVIER SCIENCE INC. 2023: S930-S931
  • Molecular Landscape and Clinical Behavior of Stage I p53-Abnormal Low-Grade Endometrioid Endometrial Carcinomas Vermij, L., Jamieson, A., Carlson, J., Howitt, B., Ip, P., Lax, S., McCluggage, W., Singh, N., McAlpine, J., Nout, R., Creutzberg, C., Horeweg, N., Bosse, T., Gilks, C. ELSEVIER SCIENCE INC. 2023: S995-S996
  • TCGA Molecular Subgroup Shows Greater Prognostic Significance Than Histologic Diagnosis in High-Grade Endometrial Carcinomas with Spindled, Undifferentiated and Sarcomatous Components Hammer, P., Wang, A., Zdravkovic, S., Heilbroner, L., Ryan, E., Mills, A., Jenkins, T., Howitt, B. ELSEVIER SCIENCE INC. 2023: S913-S914
  • Polarization of Endothelial and Epithelial Cell States Predicts Recurrence in Endometrial Endometrioid Carcinoma Nief, C., Hammer, P., Wang, A., Gentles, A., Howitt, B. ELSEVIER SCIENCE INC. 2023: S962-S963
  • Molecular Correlates of Invasion Pattern in HPV-Associated Endocervical Adenocarcinoma: Emergence of Two Distinct Risk-Stratified Tiers. Histopathology Sharma, A. E., Hodgson, A. J., Howitt, B. E., Olkhov-Mitsel, E., Djordevic, B., Park, K. J., Nucci, M. R., Parra-Herran, C. 2023


    The pattern-based (Silva) classification of invasive HPV-associated endocervical adenocarcinomas (HPVA) is an established and reproducible method to predict outcomes for this otherwise stage-dependent group of tumors. Previous studies utilizing targeted sequencing have shown a correlation between mutational profiles and invasive pattern. However, such correlation has not been explored using comprehensive molecular testing.Clinicopathologic data including invasive pattern (Silva groups A, B, and C) was collected for a cohort of invasive HPVA, which previously underwent massive parallel sequencing using a panel covering 447 genes. Pathogenic alterations, molecular signatures, tumor mutational burden (TMB), and copy number alterations (CNA) were correlated with pattern of invasion.45 HPVA (11 pattern A, 17 pattern B and 17 pattern C tumors) were included. Patients with pattern A presented at stage I with no involved lymph nodes or evidence of recurrence (in those with > 2 months of follow-up). Patterns B and C patients also mostly presented at stage I with negative lymph nodes but had greater frequency of recurrence. 3/17 pattern B and 1/17 pattern C HPVAs harbored lymphovascular space invasion (LVI). APOBEC mutational signature was detected only in Silva pattern C tumors (5/17), and pathogenic PIK3CA changes were detected only in destructively invasive HPVA (patterns B and C). When cases were grouped as low-risk (pattern A and pattern B without LVI) and high-risk (pattern B with LVI and pattern C), high-risk tumors were enriched in mutations in PIK3CA, ATRX, and ERBB2. There was a statistically significant difference in TMB between low-risk and high-risk pattern tumors (p=0.006), as well as between Pattern C tumors with and without an APOBEC signature (p=0.002). CNA burden increased from pattern A to C.Our findings further indicate that key molecular events in HPVA correlate with the morphologic invasive properties of the tumor and their aggressiveness. Pattern B tumors with LVI clustered with pattern C tumors, whereas pattern B tumors without LVI approached pattern A genotypically. Our study provides a biologic foundation for consolidating the Silva system into low-risk (pattern A + B without LVI) and high-risk (pattern B with LVI and pattern C) categories.

    View details for DOI 10.1111/his.14893

    View details for PubMedID 36849702

  • PTEN Deficiency in Tubo-Ovarian High-Grade Serous Carcinoma is Associated with Poor Progression-Free Survival and is Mutually Exclusive with CCNE1 Amplification. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc Zhang, X., Wang, A., Han, L., Liang, B., Allard, G., Diver, E., Howitt, B. E. 2023; 36 (5): 100106


    As a critical tumor suppressor, PTEN has gained much attention in cancer research. Emerging evidence suggests an association between PTEN status and clinical outcome in certain tumors, and may be predictive of response to several therapies. However, the significance of PTEN deficiency in tubo-ovarian high-grade serous carcinomas (HGSCs) is still poorly understood. We evaluated PTEN expression in HGSCs and determined its clinical relevance. A cohort of 76 HGSC specimens was profiled using tissue microarray. Immunohistochemistry (IHC) of PTEN, ER, PR, AR, CD8, FOXP3, and PD-L1 was performed. Targeted gene panel testing by massively parallel sequencing was performed in 51 cases. PTEN deficiency (complete or subclonal loss) detected by IHC was identified in 13 of the 62 HGSCs (21%) and was significantly correlated with reduced expression of ER and worse first progression-free survival (P < .05) but not with PD-L1 expression, the density of intratumoral T lymphocytes, or overall survival. In our cohort, tumor progression within 1 year of PARP inhibitor therapy was found more frequently in PTEN-deficient cases than in PTEN-intact cases (100% vs 52%). Molecular profiling showed that intragenic mutation or deletion was not the predominant mechanism for PTEN inactivation in HGSCs. In addition, CCNE1 amplification was found to be mutually exclusive with PTEN deficiency at both protein and DNA levels. An analysis of the genomic data from 1702 HGSC samples deposited with The Cancer Genome Atlas database obtained from cBioPortal confirmed the low rate of detection of PTEN gene alterations and the mutually exclusive nature of PTEN loss and CCNE1 amplification in HGSCs. These findings indicate that PTEN deficiency defines a distinct clinically significant subgroup of HGSCs with a tendency for ER negativity, wild-type CCNE1 status, inferior clinical outcomes, and potential drug resistance. These tumors may benefit from PI3K pathway inhibitors in combination with other ovarian cancer regimens, which deserves further investigation.

    View details for DOI 10.1016/j.modpat.2023.100106

    View details for PubMedID 36805789

  • Reply to Comment on HPV-independent, p53-Wild-type Vulvar Intraepithelial Neoplasia: A Review of Nomenclature and the Journey to Characterize Acanthotic Precursor Lesions of the Vulva. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc Parra-Herran, C., Nucci, M. R., Singh, N., Rakislova, N., Howitt, B. E., Hoang, L., Gilks, C. B., Bosse, T., Watkins, J. C. 2023; 36 (2): 100053

    View details for DOI 10.1016/j.modpat.2022.100053

    View details for PubMedID 36853794

  • Reply to Comment on HPV-independent, p53-Wild-type Vulvar Intraepithelial Neoplasia: A Review of Nomenclature and the Journey to Characterize Acanthotic Precursor Lesions of the Vulva MODERN PATHOLOGY Parra-Herran, C., Nucci, M. R., Singh, N., Rakislova, N., Howitt, B. E., Hoang, L., Gilks, C., Bosse, T., Watkins, J. C. 2023; 36 (2)
  • High-Grade Endometrial Stromal Sarcomas With YWHAE::NUTM2 Gene Fusion Exhibit Recurrent CDKN2A Alterations and Absence of p16 Staining is a Poor Prognostic Marker. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc Kommoss, F. K., Mar, L., Howitt, B. E., Hanley, K., Turashvilli, G., Buslei, R., Irving, J. A., Dickson, B. C., Koelsche, C., Sinn, H., Schirmacher, P., von Deimling, A., Chiang, S., McCluggage, W. G., Croce, S., Stewart, C. J., Lee, C. 2023; 36 (3): 100044


    High-grade endometrial stromal sarcomas (HGESSs) are aggressive uterine tumors harboring oncogenic fusion proteins. We performed a molecular study of 36 HGESSs with YWHAE::NUTM2 gene fusion, assessing co-occurring genetic events, and showed that these tumors frequently harbor recurrent events involving the CDKN2A locus on chromosome 9p. Using array-based copy number profiling and CDKN2A fluorescence in situ hybridization, we identified homozygous and hemizygous deletions of CDKN2A in 18% and 14% of tumors (n= 22 analyzed), respectively. While all YWHAE-rearranged HGESSs with retained disomy for CDKN2A were immunohistochemically positive for p16INK4 (p16), all tumors with homozygous deletion of CDKN2A showed complete absence of p16 staining. Of the 2 tumors with a hemizygous deletion of CDKN2A, 1 showed diffuse and strong p16 positivity, whereas the other showed complete absence of staining. In the p16-negative case, we did not find intragenic mutations or DNA promoter methylation to explain the p16 protein loss, implicating other mechanisms in the regulation of protein expression. In our cohort, subclonal or complete absence of p16 staining was associated with worse overall survival compared with positive p16 staining (1-year overall survival: 28.6% vs 90.7%, respectively; n= 32; P < .001), with all 7 patients in the p16-negative group having succumbed to their disease within 2 years of diagnosis. Our results suggested CDKN2A alterations as a cooperative driver of tumorigenesis in a subset of HGESSs with the YWHAE::NUTM2 gene fusion and showed p16 to be a potential prognostic marker.

    View details for DOI 10.1016/j.modpat.2022.100044

    View details for PubMedID 36788095

  • NCCN Guidelines Insights: Cervical Cancer, Version 1.2024. Journal of the National Comprehensive Cancer Network : JNCCN Abu-Rustum, N. R., Yashar, C. M., Arend, R., Barber, E., Bradley, K., Brooks, R., Campos, S. M., Chino, J., Chon, H. S., Crispens, M. A., Damast, S., Fisher, C. M., Frederick, P., Gaffney, D. K., Gaillard, S., Giuntoli, R., Glaser, S., Holmes, J., Howitt, B. E., Lea, J., Mantia-Smaldone, G., Mariani, A., Mutch, D., Nagel, C., Nekhlyudov, L., Podoll, M., Rodabaugh, K., Salani, R., Schorge, J., Siedel, J., Sisodia, R., Soliman, P., Ueda, S., Urban, R., Wyse, E., McMillian, N. R., Aggarwal, S., Espinosa, S. 2023; 21 (12): 1224-1233


    The NCCN Guidelines for Cervical Cancer provide recommendations for all aspects of management for cervical cancer, including the diagnostic workup, staging, pathology, and treatment. The guidelines also include details on histopathologic classification of cervical cancer regarding diagnostic features, molecular profiles, and clinical outcomes. The treatment landscape of advanced cervical cancer is evolving constantly. These NCCN Guidelines Insights provide a summary of recent updates regarding the systemic therapy recommendations for recurrent or metastatic disease.

    View details for DOI 10.6004/jnccn.2023.0062

    View details for PubMedID 38081139

  • Uterine Neoplasms, Version 1.2023, NCCN Clinical Practice Guidelines in Oncology. Journal of the National Comprehensive Cancer Network : JNCCN Abu-Rustum, N., Yashar, C., Arend, R., Barber, E., Bradley, K., Brooks, R., Campos, S. M., Chino, J., Chon, H. S., Chu, C., Crispens, M. A., Damast, S., Fisher, C. M., Frederick, P., Gaffney, D. K., Giuntoli, R., Han, E., Holmes, J., Howitt, B. E., Lea, J., Mariani, A., Mutch, D., Nagel, C., Nekhlyudov, L., Podoll, M., Salani, R., Schorge, J., Siedel, J., Sisodia, R., Soliman, P., Ueda, S., Urban, R., Wethington, S. L., Wyse, E., Zanotti, K., McMillian, N. R., Aggarwal, S. 2023; 21 (2): 181-209


    Adenocarcinoma of the endometrium (also known as endometrial cancer, or more broadly as uterine cancer or carcinoma of the uterine corpus) is the most common malignancy of the female genital tract in the United States. It is estimated that 65,950 new uterine cancer cases will have occurred in 2022, with 12,550 deaths resulting from the disease. Endometrial carcinoma includes pure endometrioid cancer and carcinomas with high-risk endometrial histology (including uterine serous carcinoma, clear cell carcinoma, carcinosarcoma [also known as malignant mixed Mullerian tumor], and undifferentiated/dedifferentiated carcinoma). Stromal or mesenchymal sarcomas are uncommon subtypes accounting for approximately 3% of all uterine cancers. This selection from the NCCN Guidelines for Uterine Neoplasms focuses on the diagnosis, staging, and management of pure endometrioid carcinoma. The complete version of the NCCN Guidelines for Uterine Neoplasms is available online at

    View details for DOI 10.6004/jnccn.2023.0006

    View details for PubMedID 36791750

  • LOW-GRADE P53ABN ENDOMETRIAL CARCINOMAS EXIST AND ARE ASSOCIATED WITH A HIGH RISK OF RECURRENCE, EVEN IN LOW-STAGE DISEASE Jamieson, A., Vermij, L., Carlson, J., Howitt, B., Ip, P., Lax, S., Mccluggage, G., Singh, N., Mcalpine, J., Nout, R., Creutzberg, C., Gilks, B., Horeweg, N., Bosse, T. BMJ PUBLISHING GROUP. 2022: A94-A95
  • DNA methylation-based classification of sinonasal tumors. Nature communications Jurmeister, P., Glöß, S., Roller, R., Leitheiser, M., Schmid, S., Mochmann, L. H., Payá Capilla, E., Fritz, R., Dittmayer, C., Friedrich, C., Thieme, A., Keyl, P., Jarosch, A., Schallenberg, S., Bläker, H., Hoffmann, I., Vollbrecht, C., Lehmann, A., Hummel, M., Heim, D., Haji, M., Harter, P., Englert, B., Frank, S., Hench, J., Paulus, W., Hasselblatt, M., Hartmann, W., Dohmen, H., Keber, U., Jank, P., Denkert, C., Stadelmann, C., Bremmer, F., Richter, A., Wefers, A., Ribbat-Idel, J., Perner, S., Idel, C., Chiariotti, L., Della Monica, R., Marinelli, A., Schüller, U., Bockmayr, M., Liu, J., Lund, V. J., Forster, M., Lechner, M., Lorenzo-Guerra, S. L., Hermsen, M., Johann, P. D., Agaimy, A., Seegerer, P., Koch, A., Heppner, F., Pfister, S. M., Jones, D. T., Sill, M., von Deimling, A., Snuderl, M., Müller, K. R., Forgó, E., Howitt, B. E., Mertins, P., Klauschen, F., Capper, D. 2022; 13 (1): 7148


    The diagnosis of sinonasal tumors is challenging due to a heterogeneous spectrum of various differential diagnoses as well as poorly defined, disputed entities such as sinonasal undifferentiated carcinomas (SNUCs). In this study, we apply a machine learning algorithm based on DNA methylation patterns to classify sinonasal tumors with clinical-grade reliability. We further show that sinonasal tumors with SNUC morphology are not as undifferentiated as their current terminology suggests but rather reassigned to four distinct molecular classes defined by epigenetic, mutational and proteomic profiles. This includes two classes with neuroendocrine differentiation, characterized by IDH2 or SMARCA4/ARID1A mutations with an overall favorable clinical course, one class composed of highly aggressive SMARCB1-deficient carcinomas and another class with tumors that represent potentially previously misclassified adenoid cystic carcinomas. Our findings can aid in improving the diagnostic classification of sinonasal tumors and could help to change the current perception of SNUCs.

    View details for DOI 10.1038/s41467-022-34815-3

    View details for PubMedID 36443295

    View details for PubMedCentralID 5340732

  • Data Set for the Reporting of Carcinomas of the Vulva: Recommendations From the International Collaboration on Cancer Reporting (ICCR) INTERNATIONAL JOURNAL OF GYNECOLOGICAL PATHOLOGY Hoang, L., Webster, F., Bosse, T., Focchi, G., Gilks, C., Howitt, B. E., McAlpine, J. N., Ordi, J., Singh, N., Wong, R., Lax, S. F., McCluggage, W. 2022; 41: S8-S22


    A cogent and comprehensive pathologic report is essential for optimal patient management, cancer staging, and prognostication. This article details the International Collaboration on Cancer Reporting (ICCR) process and the development of the vulval carcinoma reporting data set. It describes the "core" and "noncore" elements to be included in pathology reports for vulval carcinoma, inclusive of clinical, macroscopic, microscopic, and ancillary testing considerations. It provides definitions and commentary for the evidence and/or consensus-based deliberations for each element included in the data set. The commentary also discusses controversial issues, such as p16/human papillomavirus testing, tumor grading and measurements, as well as elements that show promise and warrant further evidence-based study. A summary and discussion of the updated vulval cancer staging system by the International Federation of Obstetricians and Gynaecologists (FIGO) in 2021 is also provided. We hope the widespread implementation of this data set will facilitate consistent and accurate reporting, data collection, comparison of epidemiological and pathologic parameters between different populations, facilitate research, and serve as a platform to improve patient outcomes.

    View details for DOI 10.1097/PGP.0000000000000900

    View details for Web of Science ID 000874872500003

    View details for PubMedID 36305532

  • Data Set for the Reporting of Carcinomas of the Vagina: Recommendations From the International Collaboration on Cancer Reporting (ICCR) INTERNATIONAL JOURNAL OF GYNECOLOGICAL PATHOLOGY Wong, R., Webster, F., Bosse, T., Focchi, G., Gilks, C., Hoang, L., Howitt, B. E., McAlpine, J., Ordi, J., Singh, N., Lax, S. F., McCluggage, W. 2022; 41: S23-S33


    Primary carcinomas of the vagina are uncommon and currently detailed recommendations for the reporting of resection specimens of these neoplasms are not widely available. The International Collaboration on Cancer Reporting (ICCR) is developing standardized, evidence-based reporting data sets for multiple cancer sites. We describe the development of a cancer data set by the ICCR expert panel for the reporting of primary vaginal carcinomas and present the core and noncore data elements with explanatory commentaries. This data set has incorporated the updates in the 2020 World Health Organization Classification of Female Genital Tumours, 5th edition. The data set addresses controversial issues such as tumor grading, margin assessment, and the role of ancillary studies. The adoption of this data set into clinical practice will help ensure standardized data collection across different countries, facilitate future research on vaginal carcinomas, and ultimately lead to improvements in patient care.

    View details for DOI 10.1097/PGP.0000000000000883

    View details for Web of Science ID 000874872500004

    View details for PubMedID 35703457

  • Data Set for Reporting of Uterine Malignant and Potentially Malignant Mesenchymal Tumors: Recommendations From the International Collaboration on Cancer Reporting (ICCR) INTERNATIONAL JOURNAL OF GYNECOLOGICAL PATHOLOGY Nucci, M. R., Webster, F., Croce, S., George, S., Howitt, B. E., Ip, P. C., Lee, C., Rabban, J. T., Soslow, R. A., van der Griend, R., Lax, S. F., McCluggage, W. 2022; 41: S44-S63


    The International Collaboration on Cancer Reporting (ICCR) seeks to produce standardized, evidence-based protocols for the reporting of tumors with the aim of ensuring that all cancer reports generated worldwide will be of similar high quality and record the same elements. Herein, we describe the development of the data set for the reporting of uterine malignant and potentially malignant mesenchymal tumors by a panel of expert pathologists and a single clinician and provide the commentary and rationale for the inclusion of core and noncore elements. This data set, which incorporates the recent updates from the 5th edition of the World Health Organization Classification of Female Genital Tumors, addresses several subjects of debate including which mesenchymal tumors should be graded, how to document extent of invasion, mitotic counts, and the role of ancillary testing in tumor diagnosis and patient management. The inclusion of elements is evidence-based or based on consensus of the expert panel with clinical relevance being the guiding standard.

    View details for DOI 10.1097/PGP.0000000000000911

    View details for Web of Science ID 000874872500006

    View details for PubMedID 36305534

  • Mismatch Repair and Microsatellite Instability Testing for Immune Checkpoint Inhibitor Therapy. Archives of pathology & laboratory medicine Bartley, A. N., Mills, A. M., Konnick, E., Overman, M., Ventura, C. B., Souter, L., Colasacco, C., Stadler, Z. K., Kerr, S., Howitt, B. E., Hampel, H., Adams, S. F., Johnson, W., Magi-Galluzzi, C., Sepulveda, A. R., Broaddus, R. R. 2022


    The US Food and Drug Administration (FDA) approved immune checkpoint inhibitor therapy for patients with advanced solid tumors that have DNA mismatch repair defects or high levels of microsatellite instability; however, the FDA provided no guidance on which specific clinical assays should be used to determine mismatch repair status.To develop an evidence-based guideline to identify the optimal clinical laboratory test to identify defects in DNA mismatch repair in patients with solid tumor malignancies who are being considered for immune checkpoint inhibitor therapy.The College of American Pathologists convened an expert panel to perform a systematic review of the literature and develop recommendations. Using the National Academy of Medicine-endorsed Grading of Recommendations Assessment, Development and Evaluation approach, the recommendations were derived from available evidence, strength of that evidence, open comment feedback, and expert panel consensus. Mismatch repair immunohistochemistry, microsatellite instability derived from both polymerase chain reaction and next-generation sequencing, and tumor mutation burden derived from large panel next-generation sequencing were within scope.Six recommendations and 3 good practice statements were developed. More evidence and evidence of higher quality were identified for colorectal cancer and other cancers of the gastrointestinal (GI) tract than for cancers arising outside the GI tract.An optimal assay depends on cancer type. For most cancer types outside of the GI tract and the endometrium, there was insufficient published evidence to recommend a specific clinical assay. Absent published evidence, immunohistochemistry is an acceptable approach readily available in most clinical laboratories.

    View details for DOI 10.5858/arpa.2021-0632-CP

    View details for PubMedID 35920830

  • Technetium Tc 99m tilmanocept fails to detect sentinel lymph nodes in endometrial cancer. Gynecologic oncology reports Reddy, R. A., Moon, A. S., Chow, S., Heilbroner, L., Howitt, B., Diver, E., Dorigo, O., Litkouhi, B., Renz, M., Karam, A. 2022; 43: 101054


    Technetium Tc 99m tilmanocept is a synthetic radiotracer specifically designed for sentinel lymph node (SLN) mapping that has been FDA-approved in breast cancer, melanoma, and head and neck cancer. No published studies exist for the use of this radiotracer in endometrial cancer.The primary objective was to determine the detection rate of bilateral SLNs in endometrial cancer with the concurrent use of technetium Tc 99m tilmanocept and ICG.An open-label, single cohort, prospective feasibility study was conducted with participants receiving preoperative cervical injections of technetium Tc 99m tilmanocept followed by subsequent imaging and SPECT/CT. Intraoperative ICG injections were administered for all patients with near-infrared imaging used to visualize lymphatic vessels and nodes. A laparoscopic gamma counter was used to detect radioactive SLN intraoperatively.All six evaluated patients had FIGO grade 1 or 2 endometrioid histology. Stage IA/IB were in 33% and 66% of patients, respectively. Tilmanocept did not map any SLN in the first six patients but instead showed retention of the tracer in the cervical stroma, leading to study discontinuation for futility. ICG mapped bilateral SLN in all patients with the most common location being the external iliac region, followed by the obturator and common iliac areas. All patients had CD206 positive staining throughout the full wall thickness of ectocervix, transformation zone, endocervix, and lymphatic vessels. No patients experienced adverse events.Technetium Tc 99m tilmanocept did not detect SLN in early stage endometrial cancers and is unlikely to improve bilateral detection rate compared to ICG alone. ICG remains a standard technique for SLN detection in low stage, low grade endometrial cancer.

    View details for DOI 10.1016/j.gore.2022.101054

    View details for PubMedID 35958955

    View details for PubMedCentralID PMC9361318

  • A Subset of SMARCB1 (INI-1) Deficient Vulvar Neoplasms Express Germ Cell Markers. Histopathology Hammer, P. M., Kolin, D. L., Charville, G. W., McCluggage, W. G., Howitt, B. E. 2022


    SMARCB1 (INI-1) deficient vulvar neoplasms comprise a group of rare tumors that include epithelioid sarcoma (ES), myoepithelial carcinoma (MEC), the recently described myoepithelioma-like tumor of the vulvar region (MELTVR), and sarcomas which are difficult to classify. It has been suggested that so-called vulvar yolk sac tumors (YST) may represent morphologic variants of SMARCB1-deficient tumors; thus we investigated the immunoreactivity of germ cell markers in SMARCB1-deficient vulvar neoplasms.Ten SMARCB1-deficient vulvar neoplasms were stained with germ cell tumor markers (SALL4, glypican-3, OCT3/4, and AFP) and re-reviewed for morphologic features. The tumors occurred in adult females (median age 41 years) and included ES (n=7), MELTVR (n=2), and MEC (n=1). All cases showed loss of SMARCB1 expression. Four cases (40%) were focally positive for SALL4 in areas with morphology of typical-appearing ES. One of these cases also showed focal staining for OCT3/4. One ES showed a transition from typical-appearing ES to YST-like morphology, with diffuse expression of SALL4 and glypican-3, and focal expression of AFP, in these latter areas. All other tested cases were negative for AFP.Our study reveals that SALL4, glypican-3, and OCT3/4 are positive in a subset of SMARCB1-deficient vulvar neoplasms, which may pose a diagnostic challenge and result in consideration of a germ cell tumor. We also highlight a case with transition from ES to YST-like morphology, lending further support that YSTs of the vulva are somatically derived SMARCB1-deficient neoplasms and do not represent true germ-cell neoplasia.

    View details for DOI 10.1111/his.14709

    View details for PubMedID 35758187

  • Single-cell multi-omic profiling and clonal tracing of the human gynecological tumor microenvironment Liu, V., Sandor, K., Daniel, B., Berthoin, L., Sabri, S., Panagiotopoulou, S., Yin, Y., Hiam-Galvez, K., Sit, R., Fan, Z., Galvin, B., Khan, O., Bezman, N., Grogan, J., Howitt, B., Zheng, G., Lareau, C., Satpathy, A. AMER ASSOC CANCER RESEARCH. 2022
  • GRM1 Immunohistochemistry Distinguishes Chondromyxoid Fibroma From its Histologic Mimics. The American journal of surgical pathology Toland, A. M., Lam, S. W., Varma, S., Wang, A., Howitt, B. E., Kunder, C. A., Kerr, D. A., Szuhai, K., Bovée, J. V., Charville, G. W. 2022


    Chondromyxoid fibroma (CMF) is a rare benign bone neoplasm that manifests histologically as a lobular proliferation of stellate to spindle-shaped cells in a myxoid background, exhibiting morphologic overlap with other cartilaginous and myxoid tumors of bone. CMF is characterized by recurrent genetic rearrangements that place the glutamate receptor gene GRM1 under the regulatory control of a constitutively active promoter, leading to increased gene expression. Here, we explore the diagnostic utility of GRM1 immunohistochemistry as a surrogate marker for GRM1 rearrangement using a commercially available monoclonal antibody in a study of 230 tumors, including 30 CMF cases represented by 35 specimens. GRM1 was positive by immunohistochemistry in 97% of CMF specimens (34/35), exhibiting moderate to strong staining in more than 50% of neoplastic cells; staining was diffuse (>95% of cells) in 25 specimens (71%). Among the 9 CMF specimens with documented exposure to acid decalcification, 4 (44%) exhibited diffuse immunoreactivity (>95%) for GRM1, whereas all 15 CMF specimens (100%) with lack of exposure to decalcification reagents were diffusely immunoreactive (P=0.003). High GRM1 expression at the RNA level was previously observed by quantitative reverse transcription polymerase chain reaction in 9 CMF cases that were also positive by immunohistochemistry; low GRM1 expression was observed by quantitative reverse transcription polymerase chain reaction in the single case of CMF that was negative by immunohistochemistry. GRM1 immunohistochemistry was negative (<5%) in histologic mimics of CMF, including conventional chondrosarcoma, enchondroma, chondroblastoma, clear cell chondrosarcoma, giant cell tumor of the bone, fibrous dysplasia, chondroblastic osteosarcoma, myoepithelial tumor, primary aneurysmal bone cyst, brown tumor, phosphaturic mesenchymal tumor, CMF-like osteosarcoma, and extraskeletal myxoid chondrosarcoma. These results indicate that GRM1 immunohistochemistry may have utility in distinguishing CMF from its histologic mimics.

    View details for DOI 10.1097/PAS.0000000000001921

    View details for PubMedID 35650682

  • HPV-independent, p53-wild-type vulvar intraepithelial neoplasia: a review of nomenclature and the journey to characterize verruciform and acanthotic precursor lesions of the vulva. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc Parra-Herran, C., Nucci, M. R., Singh, N., Rakislova, N., Howitt, B. E., Hoang, L., Gilks, C. B., Bosse, T., Watkins, J. C. 2022


    Vulvar squamous cell carcinomas and their precursors are currently classified by the World Health Organization based on their association with high-risk human papillomavirus (HPV). HPV independent lesions often harbor driver alterations in TP53, usually seen in the setting of chronic vulvar inflammation. However, a group of pre-invasive vulvar squamous lesions is independent from both HPV and mutant TP53. The lesions described within this category feature marked acanthosis, verruciform growth and altered squamous maturation, and over the last two decades several studies have added to their characterization. They have a documented association with verrucous carcinoma and conventional squamous cell carcinoma of the vulva, suggesting a precursor role. They also harbor recurrent genomic alterations in several oncogenes, mainly PIK3CA and HRAS, indicating a neoplastic nature. In this review, we provide a historical perspective and a comprehensive description of these lesions. We also offer an appraisal of the terminology used over the years, going from Vulvar Acanthosis with Altered Differentiation and Verruciform Lichen Simplex Chronicus to Differentiated Exophytic Vulvar Intraepithelial Lesion and Vulvar Aberrant Maturation, the latter term having been recently proposed by the International Society for the Study of Vulvovaginal Diseases. In line with the recognition of these lesions by the 2020 World Health Organization Classification of Tumours as a neoplastic precursor, we herein propose the term HPV-independent, p53-wild-type verruciform acanthotic Vulvar Intraepithelial Neoplasia (HPVi(p53wt) vaVIN), which better conveys not only the pathology but also the neoplastic nature and the biologic risk inherent to these uncommon and challenging lesions. We outline strict morphologic and immunohistochemical criteria for its diagnosis and distinction from mimickers. Immunohistochemistry for p16 and p53 should be performed routinely in the diagnostic work-up of these lesions, and the morphologic alternative term vaVIN should be reserved for instances in which p16/HPV/p53 status is unknown. We also discuss management considerations and the need to further explore precursors within and beyond the spectrum of verruciform acanthotic vulvar intraepithelial neoplasia.

    View details for DOI 10.1038/s41379-022-01079-7

    View details for PubMedID 35437330

  • Classification of Uterine Mesenchymal Neoplasms by Deep Learning Algorithms Storozuk, T., Zhu, A., Kochanny, S., Dolezal, J., Chapel, D., Howitt, B., Kolin, D., Neville, G., Nucci, M., Oliva, E., Ordulu, Z., Pinto, A., Rabban, J., Pearson, A., Bennett, J. SPRINGERNATURE. 2022: 832-833
  • A Subset of SMARCB1 (INI-1) Deficient Vulvar Neoplasms are Positive for Germ Cell Markers Hammer, P., McCluggage, W., Kolin, D., Howitt, B. SPRINGERNATURE. 2022: 755-756
  • PTEN Loss in High-Grade Serous Carcinomas is Associated with Reduced Expression of Hormonal Receptors and Poor Progression-Free Survival, and Mutually Exclusive with CCNE1 Amplification Zhang, X., Han, L., Liang, B., Wang, A., Howitt, B. SPRINGERNATURE. 2022: 856-858
  • MMR, PD-L1, and MHC Class I and Response to Checkpoint Inhibitor Therapy in Endometrial Carcinomas Makia, N., Howitt, B., Gaughan, E., Ring, K., Mills, A. SPRINGERNATURE. 2022: 794-795
  • SMARCA4-Deficient Uterine Sarcoma Harbor a Specific DNA Methylation Profile Distinct from Undifferentiated Endometrial Carcinoma and Other SWI/SNF-Deficient Tumors Kommoss, F., Tessier-Cloutier, B., Koelsche, C., Koebel, M., Lee, C., Kolin, D., von Deimling, A., Howitt, B. SPRINGERNATURE. 2022: 780-781
  • Classification of Uterine Mesenchymal Neoplasms by Deep Learning Algorithms Storozuk, T., Zhu, A., Kochanny, S., Dolezal, J., Chapel, D., Howitt, B., Kolin, D., Neville, G., Nucci, M., Oliva, E., Ordulu, Z., Pinto, A., Rabban, J., Pearson, A., Bennett, J. SPRINGERNATURE. 2022: 832-833
  • Immunohistochemical Screening for Mesonephric-like Endometrial Carcinoma: Morphologic and Molecular Features of Screen-Positive Cases Mills, A., Jenkins, T., Howitt, B., Fan, J., Ring, K., Cook, I. SPRINGERNATURE. 2022: 802-803
  • Molecular Correlates of Invasion Pattern in HPV-Associated Endocervical Adenocarcinoma: Emergence of Two Distinct Risk-Stratified Tiers Sharma, A., Hodgson, A., Howitt, B., Djordjevic, B., Park, K., Nucci, M., Parra-Herran, C. SPRINGERNATURE. 2022: 826-827
  • SDHB knockout and succinate accumulation are insufficient for tumorigenesis but dual SDHB/NF1 loss yields SDHx-like pheochromocytomas. Cell reports Armstrong, N., Storey, C. M., Noll, S. E., Margulis, K., Soe, M. H., Xu, H., Yeh, B., Fishbein, L., Kebebew, E., Howitt, B. E., Zare, R. N., Sage, J., Annes, J. P. 2022; 38 (9): 110453


    Inherited pathogenic succinate dehydrogenase (SDHx) gene mutations cause the hereditary pheochromocytoma and paraganglioma tumor syndrome. Syndromic tumors exhibit elevated succinate, an oncometabolite that is proposed to drive tumorigenesis via DNA and histone hypermethylation, mitochondrial expansion, and pseudohypoxia-related gene expression. To interrogate this prevailing model, we disrupt mouse adrenal medulla SDHB expression, which recapitulates several key molecular features of human SDHx tumors, including succinate accumulation but not 5hmC loss, HIF accumulation, or tumorigenesis. By contrast, concomitant SDHB and the neurofibromin 1 tumor suppressor disruption yields SDHx-like pheochromocytomas. Unexpectedly, invivo depletion of the 2-oxoglutarate (2-OG) dioxygenase cofactor ascorbate reduces SDHB-deficient cell survival, indicating that SDHx loss may be better tolerated by tissues with high antioxidant capacity. Contrary to the prevailing oncometabolite model, succinate accumulation and 2-OG-dependent dioxygenase inhibition are insufficient for mouse pheochromocytoma tumorigenesis, which requires additional growth-regulatory pathway activation.

    View details for DOI 10.1016/j.celrep.2022.110453

    View details for PubMedID 35235785

  • Selection of Endometrial Carcinomas For POLE Testing: Specificity Analysis of Morphologic Features Keyhanian, K., Han, L., Howitt, B., Longacre, T. SPRINGERNATURE. 2022: 774-776
  • Molecular Correlates of Invasion Pattern in HPV-Associated Endocervical Adenocarcinoma: Emergence of Two Distinct Risk-Stratified Tiers Sharma, A., Hodgson, A., Howitt, B., Djordjevic, B., Park, K., Nucci, M., Parra-Herran, C. SPRINGERNATURE. 2022: 826-827
  • Selection of Endometrial Carcinomas For POLE Testing: Specificity Analysis of Morphologic Features Keyhanian, K., Han, L., Howitt, B., Longacre, T. SPRINGERNATURE. 2022: 774-776
  • Succinate Accumulation Is Not Sufficient for Tumorigenesis in Mouse Chromaffin Cells But Dual Loss of SDHB and NF1 Yields SDHx-Like Pheochromocytomas Armstrong, N., Storey, C. M., Noll, S. E., Margulis, K., Soe, M. H., Xu, H., Yeh, B., Fishbein, L., Kebebew, E., Howitt, B. E., Zare, R. N., Sage, J., Annes, J. P. LIPPINCOTT WILLIAMS & WILKINS. 2022: E32-E33
  • Immunohistochemical Screening for Mesonephric-like Endometrial Carcinoma: Morphologic and Molecular Features of Screen-Positive Cases Mills, A., Jenkins, T., Howitt, B., Fan, J., Ring, K., Cook, I. SPRINGERNATURE. 2022: 802-803
  • A Subset of SMARCB1 (INI-1) Deficient Vulvar Neoplasms are Positive for Germ Cell Markers Hammer, P., McCluggage, W., Kolin, D., Howitt, B. SPRINGERNATURE. 2022: 755-756
  • PTEN Loss in High-Grade Serous Carcinomas is Associated with Reduced Expression of Hormonal Receptors and Poor Progression-Free Survival, and Mutually Exclusive with CCNE1 Amplification Zhang, X., Han, L., Liang, B., Wang, A., Howitt, B. SPRINGERNATURE. 2022: 856-858
  • MMR, PD-L1, and MHC Class I and Response to Checkpoint Inhibitor Therapy in Endometrial Carcinomas Makia, N., Howitt, B., Gaughan, E., Ring, K., Mills, A. SPRINGERNATURE. 2022: 794-795
  • SMARCA4-Deficient Uterine Sarcoma Harbor a Specific DNA Methylation Profile Distinct from Undifferentiated Endometrial Carcinoma and Other SWI/SNF-Deficient Tumors Kommoss, F., Tessier-Cloutier, B., Koelsche, C., Koebel, M., Lee, C., Kolin, D., von Deimling, A., Howitt, B. SPRINGERNATURE. 2022: 780-781
  • Cellular context determines DNA methylation profiles in SWI/SNF-deficient cancers of the gynecologic tract. The Journal of pathology Kommoss, F. K., Tessier-Cloutier, B., Witkowski, L., Forgo, E., Koelsche, C., Kobel, M., Foulkes, W. D., Lee, C., Kolin, D. L., von Deimling, A., Howitt, B. E. 2022


    SWI/SNF (SWItch/Sucrose Non-Fermentable) complex deficiency has been reported in a wide variety of cancers and is often associated with an undifferentiated phenotype. In the gynecologic tract SWI/SNF deficient cancers are diagnostically challenging and little is known about their cellular origins. Here we show that undifferentiated endometrial carcinoma (UDEC), SMARCA4-deficient uterine sarcoma (SDUS) and ovarian small cell carcinoma, hypercalcemic type (SCCOHT) harbor distinct DNA methylation signatures despite shared morphology and SWI/SNF inactivation. Our results indicate that cellular context is an important determinant of the epigenetic landscape, even in the setting of core SWI/SNF deficiency, and therefore methylation profiling may represent a useful diagnostic tool in undifferentiated, SWI/SNF-deficient cancers. Furthermore, applying copy number analyses and group-wise differential methylation analyses including endometrioid endometrial carcinomas and extracranial malignant rhabdoid tumors, we uncover analogous molecular features in SDUS and SCCOHT in contrast to UDEC. These results suggest SDUS and SCCOHT to represent chromosomally stable SWI/SNF deficient cancers of the gynecologic tract, which are within the broader spectrum of malignant rhabdoid tumors. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1002/path.5889

    View details for PubMedID 35218556

  • Mesonephric-like Endometrial Carcinoma: Results From Immunohistochemical Screening of 300 Endometrial Carcinomas and Carcinosarcomas for This Often Overlooked and Potentially Aggressive Entity. The American journal of surgical pathology Mills, A. M., Jenkins, T. M., Howitt, B. L., Fan, J., Ring, K. L., Cook, I. 2022


    Mesonephric-like endometrial carcinoma is a rare but frequently misclassified and aggressive malignancy. KRAS mutations, limited estrogen receptor (ER) expression, and TTF-1, GATA3, and luminal CD10 expression are described in these tumors, but an immunohistochemistry-based screening approach has not been studied. We assessed 300 endometrial carcinomas/carcinosarcomas to ascertain the specificity of TTF-1/GATA3/luminal CD10 expression with or without ER staining for this diagnosis. Next-generation sequencing and morphologic review were performed on screen-positive cases. In all, 3% (9/300) were TTF-1+; 2 coexpressed GATA3. No cases expressed luminal CD10 or GATA3 in isolation. Two TTF-1+/ER- cases, one of which was also GATA3+, were reclassified as mesonephric-like based on morphology and molecular results (KRAS mutations without mismatch repair deficiency, TP53 mutations, or PTEN mutations): these represented 0.7% of all cases (2/300). The reclassified cases were originally diagnosed as grade 1 and 2 endometrioid carcinoma, and the latter had pulmonary metastases and pelvic recurrences. Six TTF-1+ cases retained their original serous (3) and endometrioid (3) diagnoses; 1 was reclassified as dedifferentiated. All had negative or low ER. KRAS mutations were identified in 4 TTF-1+ non-mesonephric-like cases, including 1 serous and 1 grade 3 endometrioid with p53 abnormalities, 1 mismatch repair-deficient endometrioid with a complex molecular profile, and 1 endometrioid with mucinous differentiation. These findings suggest that TTF-1 and ER are good first-line screens for mesonephric-like carcinoma, but caution that a TTF-1+/ER- immunoprofile is not specific, even in the setting of KRAS mutations. A final diagnosis of mesonephric-like carcinoma requires integration of morphologic and immunohistochemical features, with molecular support when relevant.

    View details for DOI 10.1097/PAS.0000000000001873

    View details for PubMedID 35195579

  • A Multiplex SNaPshot Assay is a Rapid and Cost-Effective Method for Detecting POLE Exonuclease Domain Mutations in Endometrial Carcinoma. International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Devereaux, K. A., Steiner, D. F., Ho, C., Gomez, A. J., Gilks, B., Longacre, T. A., Zehnder, J. L., Howitt, B. E., Suarez, C. J. 1800


    Determining the replicative DNA polymerase epsilon (POLE) mutation status in endometrial carcinomas (ECs) has important clinical implications given that the majority of "ultramutated" tumors harboring pathogenic exonuclease domain mutations in POLE (POLEmut) have a favorable prognosis, even among high-grade histotypes. Currently, there are no specific morphologic or immunophenotypic features that allow accurate detection of POLEmut tumors without molecular testing. Consequently, identifying POLEmut tumors has been challenging without employing costly and/or time-consuming DNA sequencing approaches. Here we developed a novel SNaPshot assay to facilitate routine and efficient POLE mutation testing in EC. The SNaPshot assay interrogates 15 nucleotide sites within exons 9, 11, 13, and 14 encoding the POLE exonuclease domain. The variant sites were selected based on recurrence, evidence of functional impact, association with high tumor mutation burden and/or detection in EC clinical outcome studies. Based on the pathogenic somatic variants reported in the literature, the assay is predicted to have a clinical sensitivity of 90% to 95% for ECs. Validation studies showed 100% specificity and sensitivity for the variants covered, with expected genotypic results for both the positive (n=11) and negative (n=20) patient controls on multiple repeat tests and dilution series. Analytic sensitivity was conservatively approximated at a 10% variant allele fraction (VAF), with documented detection as low as 5% VAF. As expected, the SNaPshot assay demonstrated greater sensitivity than Sanger sequencing for VAFs below 20%, an important characteristic for somatic mutation detection. Here we have developed and validated the first SNaPshot assay to detect hotspot POLE mutations. While next-generation sequencing and Sanger sequencing-based approaches have also been used to detect POLE mutations, a SNaPshot approach provides useful balance of analytical sensitivity, cost-effectiveness, and efficiency in a high-volume case load setting.

    View details for DOI 10.1097/PGP.0000000000000841

    View details for PubMedID 34907997

  • Intravascular adenomyomatosis: a morphologic variant of intravenous leiomyomatosis associated with endometriosis and potential for misdiagnosis. Human pathology Fitzpatrick, M. B., Hammer, P. M., Yang, E. J., Howitt, B. E. 2021


    Intravenous leiomyomatosis (IVL) is a quasi-malignant smooth muscle tumor involving lymphatic and venous spaces of the myometrium. Rare cases of IVL with admixed endometrial glands and stroma have been described, termed intravascular adenomyomatosis. We report four additional cases of intravascular adenomyomatosis and expand the clinicopathologic features of these rare tumors. Patients were 39-45 years old and presented with symptoms of dysmenorrhea, postmenopausal bleeding, or pelvic mass. All cases were associated with endometriosis. Three cases comprised intravascular bland smooth muscle tumors with plexiform features, and in some foci the intravascular tumor contained endometrial type glands and stroma. In one case there was extensive (>10) foci of intravascular adenomyomatosis without evidence of associated smooth muscle neoplasm but did have an endometrial polyp with adenomyomatous features. None of the cases had nuclear atypia, increased mitotic activity, or tumor cell necrosis. The endometrial stromal components were positive for CD10 and negative or weakly positive for desmin by immunohistochemistry. Two cases underwent molecular testing for JAZF1 and PHF1 rearrangements with negative results. Three patients had no evidence of disease at the time of last follow-up, and one had persistent but stable disease 7 years after incomplete surgical removal and megestrol acetate treatment. Intravascular adenomyomatosis is a variant morphology rarely seen in IVL that lacks characteristic morphologic and molecular features of endometrial stromal sarcoma. Like IVL, prognosis is likely linked to completeness of surgical resection. In this study we found that intravascular adenomyomatosis is frequently associated with endometriosis, a novel finding to add to the literature on this rare IVL variant.

    View details for DOI 10.1016/j.humpath.2021.11.009

    View details for PubMedID 34856302

  • Atypical uterine polyps show morphologic and molecular overlap with mullerian adenosarcoma but follow a benign clinical course. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc Chapel, D. B., Howitt, B. E., Sholl, L. M., Dal Cin, P., Nucci, M. R. 2021


    A subset of clinically benign uterine polyps shows atypical morphologic features worrisome for, but not diagnostic of, Mullerian adenosarcoma. We report clinicopathologic data for 63 polyps from 58 women with atypical morphologic features including abnormal architecture, abnormal periglandular stroma, stromal atypia, and mitoses >2 per 10 hpf. Four (11%) of 36 women with follow-up tissue sampling had residual/recurrent atypical polyp. Twelve (27%) of 44 women underwent hysterectomy subsequent to a diagnosis of atypical polyp. No patient developed adenosarcoma over median follow-up of 150 months. Twenty-one primary atypical polyps underwent molecular profiling. Five (24%) harbored chr 12q13-15 gain or amplification, 9/20 (45%) harbored chr 6q25.1 gain, and 7/21 (33%) had no significant copy number alterations. Gains of chr 1q, chr 8p12, and chr 10q11.21-23, amplifications of chr 12q24.12-13, chr 15p24.1-26.1, and chr 18q21.33, and loss of chr 7 and chr 11q21 were each seen in a single polyp. Mean tumor mutational burden was 3.1 (range, 0.76-8.365) mutations/Mb. Pathogenic point mutations were identified in 12/20 (60%) primary atypical polyps. We propose the term "atypical uterine polyps" for these lesions, which show biologic overlap with early Mullerian adenosarcoma but lack molecular alterations characteristic of clinically aggressive adenosarcoma and appear to follow a benign clinical course. Conservative management with close clinical follow-up and repeat sampling can be considered for these lesions, when clinically appropriate.

    View details for DOI 10.1038/s41379-021-00946-z

    View details for PubMedID 34675347

  • MicroRNA profiling in a case-control study of African American women with uterine serous carcinoma. Gynecologic oncology Lee, L., Howitt, B., Cheng, T., King, M., Stawiski, K., Fendler, W., Chowdhury, D., Matulonis, U., Konstantinopoulos, P. A. 2021


    OBJECTIVE: Uterine serous carcinoma (USC) is an aggressive subtype of endometrial cancer associated with worse survival outcomes in African American (AA) patients. This study evaluated tumor miRNA expression by race, clinical and tumor characteristics, and survival outcomes.METHODS: FFPE tumor tissue from hysterectomy specimens was identified for 29 AA cases. Case matching was performed by computer-based random assignment in a 1:1 ratio with Caucasian controls based on age, stage and histologic subtype (pure vs. mixed). RNA was extracted from 77 specimens (54 tumors and 23 matched normal endometrium). MicroRNA array profiling was performed by microRNA Hi-Power Labeling (Hy3/Hy5) and hybridization to miRCURY LNA microRNA Array 7th Gen.RESULTS: Clinical and treatment characteristics were similar for cases and controls, although use of adjuvant radiation was less common in African Americans (p=0.03). Of 968 miRNAs analyzed, 649 were differentially expressed in normal endometrium vs. tumor. When compared by race, histologic subtype, stage or presence of LVI, no differentially expressed miRNAs were identified. In patients with disease recurrence at 3years, the three most upregulated miRNAs were miR-1, miR-21-5p and miR-223. Of these, increased miR-223 expression (>median) was associated with worse OS (p=0.0496) in an independent dataset (TCGA dataset) comprising of 140 patients with USC (mixed or pure serous). After adjusting for age, ethnicity and BMI, upregulation of miR-223 remained risk factor for death (adjusted HR 2.87, 95% CI 1.00-8.27).CONCLUSIONS: MiRNA profiling did not identify biological differences between AA and Caucasian patients with USC. Upregulation of miR-223 may be a prognostic factor in USC.

    View details for DOI 10.1016/j.ygyno.2021.09.015

    View details for PubMedID 34607711

  • High-grade serous ovarian tumor cells modulate NK cell function to create an immune-tolerant microenvironment. Cell reports Gonzalez, V. D., Huang, Y., Delgado-Gonzalez, A., Chen, S., Donoso, K., Sachs, K., Gentles, A. J., Allard, G. M., Kolahi, K. S., Howitt, B. E., Porpiglia, E., Fantl, W. J. 2021; 36 (9): 109632


    Tubo-ovarian high-grade serous carcinoma (HGSC) is unresponsive to immune checkpoint blockade despite significant frequencies of exhausted Tcells. Here we apply mass cytometry and uncover decidual-like natural killer (dl-NK) cell subpopulations (CD56+CD9+CXCR3+KIR+CD3-CD16-) in newly diagnosed HGSC samples that correlate with both tumor and transitioning epithelial-mesenchymal cell abundance. We show different combinatorial expression patterns of ligands for activating and inhibitory NK receptors within three HGSC tumor compartments: epithelial (E), transitioning epithelial-mesenchymal (EV), and mesenchymal (vimentin expressing [V]), with a more inhibitory ligand phenotype in V cells. In cocultures, NK-92 natural killer cells acquire CD9 from HGSC tumor cells by trogocytosis, resulting in reduced anti-tumor cytokine production and cytotoxicity. Cytotoxicity in these cocultures is restored with a CD9-blocking antibody or CD9 CRISPR knockout, thereby identifying mechanisms of immune suppression in HGSC. CD9 is widely expressed in HGSC tumors and so represents an important new therapeutic target with immediate relevance for NK immunotherapy.

    View details for DOI 10.1016/j.celrep.2021.109632

    View details for PubMedID 34469729

  • Nuclear Beta-Catenin Expression in the Context of Abnormal p53 Endometrial Carcinoma Indicates a Non-Serous Histotype Keyhanian, K., Yang, E., Howitt, B. SPRINGERNATURE. 2021: 704–5
  • Clinical Features of SARS-CoV-2 Infection During Pregnancy and Associated Placental Pathologies Brar, N., Ryan, E., Winn, V., Folkins, A., Howitt, B. SPRINGERNATURE. 2021: 656–57
  • Atypical Uterine Polyps Are Molecularly Heterogeneous and Share Genomic Features with Uterine Adenosarcoma and Banal Endometrial Polyps Chapel, D., Da Silva, A., Sholl, L., Howitt, B., Dal Cin, P., Nucci, M. SPRINGERNATURE. 2021: 663–64
  • Molecular Classification of Endometrial Carcinomas with Long-Term Follow-up Hammer, P., Albro, J., Squires, C., Peters-Schulze, G., Sharp, B., Charu, V., Cessna, M., Howitt, B. SPRINGERNATURE. 2021: 691–93
  • Nuclear Beta-Catenin Expression in the Context of Abnormal p53 Endometrial Carcinoma Indicates a Non-Serous Histotype Keyhanian, K., Yang, E., Howitt, B. SPRINGERNATURE. 2021: 704–5
  • Clinical Features of SARS-CoV-2 Infection During Pregnancy and Associated Placental Pathologies Brar, N., Ryan, E., Winn, V., Folkins, A., Howitt, B. SPRINGERNATURE. 2021: 656–57
  • Atypical Uterine Polyps Are Molecularly Heterogeneous and Share Genomic Features with Uterine Adenosarcoma and Banal Endometrial Polyps Chapel, D., Da Silva, A., Sholl, L., Howitt, B., Dal Cin, P., Nucci, M. SPRINGERNATURE. 2021: 663–64
  • Molecular Classification of Endometrial Carcinomas with Long-Term Follow-up Hammer, P., Albro, J., Squires, C., Peters-Schulze, G., Sharp, B., Charu, V., Cessna, M., Howitt, B. SPRINGERNATURE. 2021: 691–93
  • Corrigendum to "Pathological chemotherapy response score is prognostic in tubo-ovarian high-grade serous carcinoma: A systematic review and meta-analysis of individual patient data" Gynecol. Oncol. 154 (2019) 441-448. Gynecologic oncology Cohen, P. A., Powell, A., Bohm, S., Gilks, C. B., Stewart, C. J., Meniawy, T. M., Bulsara, M., Avril, S., Brockbank, E. C., Bosse, T., de Azevedo Focchi, G. R., Ganesan, R., Glasspool, R. M., Howitt, B. E., Kim, H., Lee, J., Le, N. D., Lockley, M., Manchanda, R., Mandalia, T., McCluggage, W. G., McNeish, I., Midha, D., Srinivasan, R., Tan, Y. Y., van der Griend, R., Yunokawa, M., Zannoni, G. F., HGSC CRS Collaborative Network (Supplementary 1), Singh, N. 2021

    View details for DOI 10.1016/j.ygyno.2021.01.032

    View details for PubMedID 33551198

  • A Distinctive Adnexal (Usually Paratubal) Neoplasm Often Associated With Peutz-Jeghers Syndrome and Characterized by STK11 Alterations (STK11 Adnexal Tumor): A Report of 22 Cases. The American journal of surgical pathology Bennett, J. A., Young, R. H., Howitt, B. E., Croce, S., Wanjari, P., Zhen, C., Da Cruz Paula, A., Meserve, E., Schoolmeester, J. K., Westbom-Fremer, S., Benzi, E., Patil, N. M., Kooreman, L., El-Bahrawy, M., Zannoni, G. F., Krausz, T., McCluggage, W. G., Weigelt, B., Ritterhouse, L. L., Oliva, E. 2021


    We describe 22 examples of a novel, usually paratubal, adnexal tumor associated with Peutz-Jeghers syndrome in nearly 50% of cases that harbored STK11 alterations in all tested (n=21). The patients ranged from 17 to 66 years (median=39y) and the tumors from 4.5 to 25.5cm (median=11cm). Most (n=18) were paratubal, with metastases noted in 11/22 (50%) and recurrences in 12/15 (80%). Morphologically, they were characterized by interanastomosing cords and trabeculae of predominantly epithelioid cells, set in a variably prominent myxoid to focally edematous stroma, that often merged to form tubular, cystic, cribriform, and microacinar formations, reminiscent of salivary gland-type tumors. The tumor cells were uniformly atypical, often with prominent nucleoli and a variable mitotic index (median=9/10HPFs). The tumors were usually positive to a variable extent for epithelial (CAM5.2, AE1/AE3, cytokeratin 7), sex cord (calretinin, inhibin, WT1), and mesothelial (calretinin, D2-40) markers, as well as hormone receptors. PAX8, SF1, and GATA-3 were rarely positive, while claudin-4, FOXL2, and TTF-1 were consistently negative. All sequenced tumors (n=21) harbored alterations in STK11, often with a loss of heterozygosity event. There were no other recurrently mutated genes. Recurrent copy number alterations included loss of 1p and 11q, and gain of 1q, 15q, and 15p. Despite an extensive morphologic, immunohistochemical, and molecular evaluation, we are unable to determine with certainty the histogenesis of this unique tumor. Wolffian, sex cord stromal, epithelial, and mesothelial origins were considered. We propose the term STK11 adnexal tumor to describe this novel entity and emphasize the importance of genetic counseling in these patients as a significant number of neoplasms occur in association with Peutz-Jeghers syndrome.

    View details for DOI 10.1097/PAS.0000000000001677

    View details for PubMedID 33534223

  • Ovariectomized mice and postmenopausal women exhibit analogous loss of genital epithelial integrity. Tissue barriers Quispe Calla, N. E., Vicetti Miguel, R. D., Aceves, K. M., Huang, H., Howitt, B., Cherpes, T. L. 2021: 1865760


    Roughly half of all postmenopausal women are affected by the genitourinary syndrome of menopause (GSM). Symptoms of GSM, including vaginal irritation and dyspareunia, occur as reduced estrogen (E) production elicits loss of elasticity and other changes in genital tract tissue. While the use of the injectable contraceptive depot-medroxyprogesterone acetate (DMPA) likewise lowers serum E concentrations in reproductive age women and is associated with decreased genital levels of the cell-cell adhesion molecules desmoglein-1 (DSG1) and desmocollin-1 (DSC1) and impaired genital epithelial barrier function, the relevance of these findings to women in menopause is uncertain. Exploring the impact of menopause on genital epithelial integrity herein, we detected significantly lower levels of DSG1 and DSC1 in ectocervical tissue from menopausal and postmenopausal vs premenopausal women. Using ovariectomized (OVX) mice as a menopause model, we comparably saw significantly lower vaginal tissue levels of DSG1 and DSC1 in OVX mice vs. mice in estrus. Compared to estrus-stage mice and E-treated OVX mice, DMPA-treated ovary-intact mice and OVX mice also exhibited significantly reduced genital epithelial barrier function, greater susceptibility to genital herpes simplex virus type 2 infection, and delayed clearance of genital Chlamydia trachomatis infection. Current studies thus identify analogous loss of genital epithelial integrity in OVX mice and menopausal and postmenopausal women. By showing that loss of genital epithelial integrity is associated with increased mouse susceptibility to bacterial and viral pathogens, our findings also prioritize the need to resolve if reduced genital epithelial integrity in postmenopausal women is a significant risk factor for genital infection.

    View details for DOI 10.1080/21688370.2020.1865760

    View details for PubMedID 33427560

  • Vulvar Yolk Sac Tumors Are Somatically Derived SMARCB1 (INI-1)-Deficient Neoplasms. The American journal of surgical pathology Kolin, D. L., Konstantinopoulos, P. A., Campos, S. M., Toumi, G., Kolahi, K. A., Gars, E. J., Howitt, B. E. 2021


    So-called primary yolk sac tumors of the vulva are very rare and often have an aggressive disease course. Their molecular features have not been previously characterized. There is also a well-documented group of SMARCB1 (INI-1)-deficient vulvar neoplasms, which includes proximal-type epithelioid sarcoma and myoepithelial carcinoma. Until now, "vulvar yolk sac tumors" and SMARCB1-deficient neoplasms were considered unrelated diseases. After reviewing an index case of a vulvar yolk sac tumor with loss of SMARCB1 by immunohistochemistry, we retrospectively identified 2 additional cases diagnosed as vulvar yolk sac tumors. Patient ages were 34, 32, and 25 years old, and 2 tumors were associated with a pregnancy. All 3 cases showed morphology typical of a yolk sac tumor, and by immunohistochemistry all were positive for SALL4, glypican-3, keratins, and lacked CD34 positivity. All tumors also demonstrated loss of SMARCB1 in tumor cells. Targeted molecular profiling was performed in 2 cases and identified 2 copy deletion of SMARCB1, without genomic alterations typically seen in gonadal yolk sac tumors. In the third case, isochromosome 12p was not identified by fluorescence in situ hybridization. All 3 patients had either local recurrences or distant metastases, and 2 died of disease. One patient had progressive disease while receiving the enhancer of zeste homolog 2 inhibitor tazemetostat. Overall, these findings suggest that vulvar tumors with pure yolk sac-like morphology may represent morphologic variants of SMARCB1-deficient tumors and not veritable germ cell neoplasia. This potential reclassification may have both prognostic and treatment implications and warrants study of additional extragonadal yolk sac tumors.

    View details for DOI 10.1097/PAS.0000000000001777

    View details for PubMedID 34265804

  • Prospective molecular classification of endometrial carcinomas: institutional implementation, practice, and clinical experience. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc Devereaux, K. A., Weiel, J. J., Pors, J., Steiner, D. F., Ho, C., Charu, V., Suarez, C. J., Renz, M., Diver, E., Karam, A., Litkouhi, B., Dorigo, O., Kidd, E. A., Yang, E. J., Folkins, A. K., Longacre, T. A., Howitt, B. E. 2021


    The comprehensive genomic analysis of endometrial carcinoma (EC) by The Cancer Genome Atlas (TCGA) led to the discovery of four distinct and prognostically significant molecular subgroups. Molecular classification has the potential to improve risk-stratification when integrated with clinicopathologic features and has recently been included in national and international patient management EC guidelines. Thus, the adoption of molecular classification into routine pathologic and clinical practice is likely to grow significantly in the upcoming years. Establishing an efficient and standardized workflow for performing molecular classification on ECs, and reporting both the molecular and histologic findings in an integrative manner, is imperative. Here we describe our effort to implement rapid and routine molecular classification on all ECs diagnosed at our institution. To this effect, we performed immunohistochemistry as a surrogate marker for identifying genetic and/or epigenetic alterations in DNA mismatch repair (e.g., MLH1, PMS2, MSH6, MSH2), and TP53 genes. In addition, we have developed and employed a single-gene POLE SNaPshot assay, which is a rapid and analytically sensitive method for detecting select POLE exonuclease domain mutations (EDMs). We report our molecular testing workflow and integrative reporting system as well as the clinicopathologic and molecular features of 310 ECs that underwent routine molecular classification at our institution. The 310 ECs were molecularly classified as follows: 15 (5%) POLE mutant (POLEmut), 79 (25%) mismatch repair-deficient (MMRd), 135 (44%) no specific molecular profile (NSMP), and 81 (26%) p53 abnormal (p53abnl). This work provides an initial framework for implementing routine molecular classification of ECs.

    View details for DOI 10.1038/s41379-021-00963-y

    View details for PubMedID 34743187

  • NCCN Guidelines Insights: Uterine Neoplasms, Version 3.2021. Journal of the National Comprehensive Cancer Network : JNCCN Abu-Rustum, N. R., Yashar, C. M., Bradley, K., Campos, S. M., Chino, J., Chon, H. S., Chu, C., Cohn, D., Crispens, M. A., Damast, S., Diver, E., Fisher, C. M., Frederick, P., Gaffney, D. K., George, S., Giuntoli, R., Han, E., Howitt, B., Huh, W. K., Lea, J., Mariani, A., Mutch, D., Nekhlyudov, L., Podoll, M., Remmenga, S. W., Reynolds, R. K., Salani, R., Sisodia, R., Soliman, P., Tanner, E., Ueda, S., Urban, R., Wethington, S. L., Wyse, E., Zanotti, K., McMillian, N. R., Motter, A. D. 2021; 19 (8): 888-895


    The NCCN Guidelines for Uterine Neoplasms provide recommendations for diagnostic workup, clinical staging, and treatment options for patients with endometrial cancer or uterine sarcoma. These NCCN Guidelines Insights focus on the recent addition of molecular profiling information to aid in accurate diagnosis, classification, and treatment of uterine sarcomas.

    View details for DOI 10.6004/jnccn.2021.0038

    View details for PubMedID 34416706

  • Well-differentiated lipomatous neoplasms with p53 alterations: A clinicopathologic and molecular study of eight cases with features of atypical pleomorphic lipomatous tumor. Histopathology Hammer, P. M., Kunder, C. A., Howitt, B. E., Charville, G. W. 2021


    Well-differentiated lipomatous neoplasms encompass a broad spectrum of benign and malignant tumors, many of which are characterized by recurrent genetic abnormalities. Although a key regulator of p53 signaling, MDM2, is characteristically amplified in well-differentiated liposarcoma, recurrent abnormalities of p53 itself have not been reported in well-differentiated adipocytic neoplasms. Here, we present a series of well-differentiated lipomatous tumors characterized by p53 alterations and histologic features in keeping with atypical pleomorphic lipomatous tumor (APLT).We reviewed the morphologic, immunohistochemical, and molecular genetic features of eight lipomatous tumors with p53 alterations. Four tumors arose in the thigh, and one case each arose in the shoulder, calf, upper back, and subclavicular regions; six tumors were deep/subfascial and two were subcutaneous. Relevant clinical history included two patients with Li-Fraumeni syndrome. Morphologically, all cases demonstrated well-differentiated adipocytes with prominent nuclear pleomorphism, limited mitotic activity, and no tumor cell necrosis. All cases were negative for MDM2 overexpression and amplification by immunohistochemistry and fluorescence in situ hybridization, respectively. By immunohistochemistry, p16 was diffusely overexpressed in all cases; seven tumors (88%) showed abnormal loss of Rb and p53. TP53 mutation or deletion was identified in 4 of 6 tumors evaluated by exon-targeted hybrid capture-based massively parallel sequencing; RB1 mutation or deletion was present in 5 of 6 cases.We present a series of eight well-differentiated lipomatous neoplasms characterized by p53 alterations in addition to Rb loss and histologic features of APLT. These findings suggest that impaired p53 signaling may contribute to the pathogenesis of APLT in a subset of cases.

    View details for DOI 10.1111/his.14593

    View details for PubMedID 34725851

  • Update on SWI/SNF-related Gynecologic Mesenchymal Neoplasms: SMARCA4-deficient uterine sarcoma and SMARCB1-deficient vulvar neoplasms. Genes, chromosomes & cancer Howitt, B. E., Folpe, A. L. 2020


    Our knowledge regarding the role of genes encoding the chromatin remodeling switch/sucrose non-fermenting (SWI/SNF) complex in the initiation and progression of gynecologic malignancies continues to evolve. This review focuses on gynecologic tumors in which the sole or primary genetic alteration is in SMARCA4 or SMARCB1, two members of the SWI/SNF chromatin remodeling complex. In this review we present a brief overview of the classical example of such tumors, ovarian small cell carcinoma of hypercalcemic type, and then a detailed review and update of SMARCB1-deficient and SMARCA4-deficient tumors of the uterus and vulva. This article is protected by copyright. All rights reserved.

    View details for DOI 10.1002/gcc.22922

    View details for PubMedID 33252159

  • Clinicopathologic Characteristics of Mesonephric Adenocarcinomas and Mesonephric-like Adenocarcinomas in the Gynecologic Tract: A Multi-institutional Study. The American journal of surgical pathology Pors, J., Segura, S., Chiu, D. S., Almadani, N., Ren, H., Fix, D. J., Howitt, B. E., Kolin, D., McCluggage, W. G., Mirkovic, J., Gilks, B., Park, K. J., Hoang, L. 2020


    Mesonephric adenocarcinoma (MA) and mesonephric-like adenocarcinoma (MLA) are uncommon neoplasms of the gynecologic tract that have until recently been poorly understood. Although their morphologic, immunohistochemical, and molecular profiles have been recently defined, little is known about their clinical behavior. Small studies have demonstrated inconsistent findings and no large studies have examined the clinical behavior of these adenocarcinomas. In this multi-institutional study, representing the largest and most stringently defined cohort of cases to date, we examined the clinicopathologic features of 99 MAs and MLAs (30 MAs of the uterine cervix, 44 MLAs of the endometrium, and 25 MLAs of the ovary). Only tumors with characteristic mesonephric morphology and either immunohistochemical or molecular support were included. Our results demonstrate that the majority of mesonephric neoplasms presented at an advanced stage (II to IV) (15/25 [60%] MA of the cervix, 25/43 [58%] MLA of the endometrium, and 7/18 [39%] MLA of the ovary). The majority (46/89 [52%] overall, 12/24 [50%] MA of the cervix, 24/41 [59%] MLA of the endometrium, and 10/24 [42%] MLA of the ovary) developed recurrences, most commonly distant (9/12 [75%] MA of the cervix, 22/24 [92%] MLA of the endometrium, and 5/9 [56%] MLA of the ovary). The 5-year disease-specific survival was 74% (n=26) for MA of cervix, 72% (n=43) for MLA of endometrium, and 71% (n=23) for MLA of ovary. Our results confirm that mesonephric neoplasms are a clinically aggressive group of gynecologic carcinomas that typically present at an advanced stage, with a predilection for pulmonary recurrence.

    View details for DOI 10.1097/PAS.0000000000001612

    View details for PubMedID 33165093

  • Molecular Characterization of Neuroendocrine Carcinomas of the Endometrium: Representation in All 4 TCGA Groups. The American journal of surgical pathology Howitt, B. E., Dong, F., Vivero, M., Shah, V., Lindeman, N., Schoolmeester, J. K., Baltay, M., MacConaill, L., Sholl, L. M., Nucci, M. R., McCluggage, W. G. 2020


    High-grade neuroendocrine carcinomas (NEC) of the endometrium are rare and account for <1% of all endometrial carcinomas. Both small cell neuroendocrine carcinoma (SCNEC) and large cell neuroendocrine carcinoma (LCNEC) morphologies have been reported. Little is known regarding the molecular features of endometrial NEC including how they compare to pulmonary NEC (the most common site for these neoplasms) and the more common endometrial carcinoma histotypes. In this study, we investigated the molecular alterations in a series of endometrial NEC using a targeted next generation sequencing panel (Oncopanel). Fourteen NEC were sequenced; pure NEC (n=4) and mixed (n=10) with endometrioid adenocarcinoma (n=9) or carcinosarcoma (n=1). The NEC components of mixed tumors comprised LCNEC (n=6) and SCNEC (n=4). The 4 pure NEC comprised LCNEC (n=2) and SCNEC (n=2). Molecular analysis classified tumors into the 4 The Cancer Genome Atlas groups: (1) POLE-mutated/ultramutated (1/14; 7%), (2) microsatellite instability/hypermutated (6/14; 43%), (3) TP53 mutated/copy number high (2/14; 14%), or (4) no specific molecular profile (5/14; 36%). Overall, 50% of cases were ultramutated or hypermutated. In 8 cases of mixed carcinomas, the different histologic components were macrodissected and separately sequenced; molecular alterations were nearly identical among the 2 components, with the non-NEC component harboring slightly increased tumor mutational burden. Only 2 carcinomas (both with pure SCNEC morphology) had a molecular profile that would be expected in typical pulmonary SCNEC (RB1 deletion and TP53 mutations). Our findings, similar to data from NECs of other anatomic sites, suggest that the molecular context may be important when selecting therapies for women with endometrial NEC. Immune checkpoint inhibition may be a reasonable approach to treatment of microsatellite instability-NEC and we thus recommend that all endometrial NEC be tested for mismatch repair abnormalities, either molecularly or by mismatch repair protein immunohistochemistry.

    View details for DOI 10.1097/PAS.0000000000001560

    View details for PubMedID 32773531

  • A Multiplex SNaPshot Assay is a Rapid and Cost-Effective Method for Detecting POLE Mutations in Endometrial Carcinoma Devereaux, K., Steiner, D., Ho, C., Gomez, A., Gojenola, L., Gilks, C., Longacre, T., Zehnder, J., Howitt, B., Suarez, C. NATURE PUBLISHING GROUP. 2020: 1040
  • Clinicopathologic and Immunohistochemical Correlates of CTNNB1 Mutated Endometrial Endometrioid Carcinoma INTERNATIONAL JOURNAL OF GYNECOLOGICAL PATHOLOGY Costigan, D. C., Dong, F., Nucci, M. R., Howitt, B. E. 2020; 39 (2): 119–27
  • Molecular Classification of Metastatic and Recurrent Endometrial Endometrioid Carcinoma Devereaux, K., Chow, S., Steiner, D., Peters-Schulze, G., Ho, C., Suarez, C., Folkins, A., Howitt, B. NATURE PUBLISHING GROUP. 2020: 1041–42
  • Mullerian Adenosarcoma: Clinicopathologic Features of 78 cases Kolin, D., Howitt, B., Nathenson, M., Nucci, M. NATURE PUBLISHING GROUP. 2020: 1084–85
  • P120 Catenin Staining Patterns Differentiate Mullerian Carcinosarcoma from its Mimics Acosta, A., Howitt, B., Strickland, K., Mirkovic, J., Parra-Herran, C., Hirsch, M., Kolin, D., Nucci, M. NATURE PUBLISHING GROUP. 2020: 1002–3
  • Mullerian Adenosarcoma: Clinicopathologic Features of 78 cases Kolin, D., Howitt, B., Nathenson, M., Nucci, M. NATURE PUBLISHING GROUP. 2020: 1084–85
  • Unusual Adnexal Tumors with Recurring STK11 Mutations: A Clinicopathological Study of 11 Cases Including 4 in Patients with Peutz-Jeghers Syndrome Bennett, J., Meserve, E., Howitt, B., Ritterhouse, L., Schoolmeester, J., Croce, S., Kooreman, L., El-Bahrawy, M., Zannoni, G., Krausz, T., McCluggage, W., Young, R., Oliva, E. NATURE PUBLISHING GROUP. 2020: 1016–17
  • 5-hmC Immunohistochemistry is a Reliable Marker for Predicting Leiomyomas with Fumarate Hydratase Mutations Sharma, A., Forgo, E., Howitt, B., Rabban, J., Garg, K., Bennett, J. NATURE PUBLISHING GROUP. 2020: 1134–35
  • DNA Methylation Profiling of Uterine Sarcomas Forgo, E., Lang, A., Natu, V., Longacre, T., Bennett, J., Quick, C., Parra-Herran, C., Nucci, M., Kolin, D., Howitt, B. NATURE PUBLISHING GROUP. 2020: 1056–57
  • A Multiplex SNaPshot Assay is a Rapid and Cost-Effective Method for Detecting POLE Mutations in Endometrial Carcinoma Devereaux, K., Steiner, D., Ho, C., Gomez, A., Gojenola, L., Gilks, C., Longacre, T., Zehnder, J., Howitt, B., Suarez, C. NATURE PUBLISHING GROUP. 2020: 1040
  • Vulvar sarcoma outcomes by histologic subtype: a Surveillance, Epidemiology, and End Results (SEER) database review. International journal of gynecological cancer : official journal of the International Gynecological Cancer Society Johnson, S. n., Renz, M. n., Wheeler, L. n., Diver, E. n., Dorigo, O. n., Litkouhi, B. n., Behbakht, K. n., Howitt, B. n., Karam, A. n. 2020


    Vulvar cancers account for 5% of all gynecologic malignancies; only 1%-3% of those vulvar cancers are primary vulvar sarcomas. Given the rarity of vulvar sarcomas, outcome data specific to histopathologic subtypes are sparse. The aim of this study was to identify clinical and pathologic factors of primary vulvar sarcomas that are associated with survival and may inform treatment decisions.The Surveillance, Epidemiology, and End Results (SEER) database was searched for women diagnosed with vulvar sarcoma between 1973 and 2018. We identified 315 patients and reviewed their demographic, clinicopathologic, surgical, and survival information. Statistical analyses included χ2 and t-tests, Kaplan-Meier survival, and Cox regression analyses.The most common histopathologies of vulvar sarcomas were dermatofibrosarcomas (85/315, 27%) and leiomyosarcomas (72/315, 22.9%). Rhabdomyosarcomas (18/315, 5.7%), liposarcomas (16/315, 5.1%), and malignant fibrous histiocytomas (16/315, 5.1%) were less frequent. The majority of patients underwent surgery (292/315, 92.7%), which included lymph node dissections in 21.6% (63/292). Survival and lymph node involvement varied significantly with histologic subtype. The 5-year disease-specific survival for dermatofibrosarcomas, liposarcomas, and fibrosarcomas was 100% and only 60.3% and 62.5% for malignant fibrous histiocytomas and rhabdomyosarcomas, respectively. None of the patients with (dermato)fibrosarcomas, liposarcomas, or leiomyosarcomas had positive lymph nodes, in contrast to rhabdomyosarcomas and malignant fibrous histiocytomas with 77.8% and 40% positive lymph nodes, respectively. The 5-year disease-specific survival for women with positive lymph nodes was 0%.Vulvar sarcomas are heterogeneous with survival highly dependent on the histopathologic subtype. While surgical excision is the mainstay of treatment for all vulvar sarcomas, staging lymphadenectomy should be deferred for (dermato)fibrosarcomas, liposarcomas, and leiomyosarcomas as there were no cases of lymph nodes metastases.

    View details for DOI 10.1136/ijgc-2020-001516

    View details for PubMedID 32641392

  • Criteria for Risk Stratification of Vulvar and Vaginal Smooth Muscle Tumors: A Follow Up Study with Application to Leiomyoma Variants, Smooth Muscle Tumors of Uncertain Malignant Potential (STUMP) and Leiomyosarcomas. Human pathology Swanson, A. A., Howitt, B. E., Schoolmeester, J. K. 2020


    Data have shown that uterine diagnostic criteria are universal for smooth muscle tumors (SMTs) originating in the ovary, vulva, vagina, broad ligament and other supportive connective tissue, and that uterine criteria outperform site-specific criteria for vulvar and vaginal SMTs. Classic benign and malignant spindled SMTs were well represented in our recent study comparing uterine and site-specific criteria in vulvovaginal SMTs, but leiomyoma variants and smooth muscle tumors of uncertain malignant potential (STUMPs) were relatively few. Therefore, we evaluated additional leiomyoma variants, STUMPs and leiomyosarcomas from 17 patients (10 vaginal, 7 vulvar). The 10 vaginal tumors (59%) comprised cellular leiomyoma (n=2), leiomyoma with bizarre nuclei (n=3), STUMP (n=1) and leiomyosarcoma (n=4). The 7 vulvar tumors (41%) comprised leiomyoma with bizarre nuclei (n=3), STUMP (n=1) and leiomyosarcoma (n=3). Follow up was available for 13 patients (76.5%) ranging from 1 to 97 months (mean: 17.3; median: 7). Follow up for some patients with leiomyosarcoma was limited (< 4 months for 4 patients). One vaginal STUMP locally recurred after 19 months and 2 patients diagnosed with leiomyosarcoma developed distant metastases. All remaining patients had either no evidence of disease at last follow up (10 patients, 58.8%) or their status was unknown (4 patients, 23.5%). Uterine criteria are valid for vulvovaginal leiomyoma variants and STUMPs, and more appropriately classified these tumors than site-specific criteria. Our combined findings from the current and previous studies support use of uterine diagnostic thresholds for the entire spectrum of vulvovaginal SMTs.

    View details for DOI 10.1016/j.humpath.2020.06.008

    View details for PubMedID 32687944

  • Malignant Tumors of the Uterus and Ovaries with Mullerian and Germ Cell or Trophoblastic Components Have a Somatic Origin and are Characterized by Genomic Instability. Histopathology Acosta, A. M., Sholl, L. M., Dal Cin, P. n., Howitt, B. E., Otis, C. N., Nucci, M. R. 2020


    Tumors of the female genital tract with a combination of malignant Mullerian and germ cell or trophoblastic tumor (MMGC/T) components are usually diagnosed in postmenopausal women and pursue an aggressive clinical course characterized by poor response to therapy and early relapses. These clinical features suggest that MMGC/T are somatic in origin, but objective molecular data to support this interpretation are lacking. This study evaluates the molecular features of 9 MMGC/T, including 7 tumors containing yolk sac tumor (YST), 1 tumor containing choriocarcinoma and 1 tumor containing epithelioid trophoblastic tumor. The objectives were: 1) to investigate whether MMGC/T show a distinct genetic profile and 2) to explore the relationship between the different histologic components.Next generation sequencing of paired samples demonstrated that the mutational profile of the Mullerian and non-Mullerian components of the tumor were almost identical in all cases. Moreover, the driver mutations identified were those expected in the specific subtype of Mullerian component present in each case. In contrast, variants expected in post-pubertal germ cell tumors and gestational trophoblastic tumors were not identified, and FISH for i(12p) was negative in all cases tested. In this study, mismatch repair-proficient MMGC/T (8/9) were characterized by a complex copy number variant profile including numerous focal, regional, arm-level and chromosome-level events.Comparison of paired samples supports that the YST and trophoblastic tumor components of MMGC/T have a somatic and often show numerous copy number variants suggestive of underlying genomic instability.

    View details for DOI 10.1111/his.14188

    View details for PubMedID 32558949

  • A Clinical and Pathologic Exploration of Suspected Peritoneal Endometriotic Lesions. International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Watkins, J. C., DiVasta, A. D., Vitonis, A. F., Crum, C. P., Laufer, M. R., Terry, K. L., Howitt, B. E., Missmer, S. A. 2020


    Endometriosis is generally histopathologically defined as the presence of at least 2 of the following: endometrial stroma, Müllerian epithelium, and/or hemosiderin-laden macrophages (HLM). Despite clinically evident endometriotic lesions, biopsies are frequently nondiagnostic. In this study, we conducted a large-scale review of biopsies of lesions clinically thought to represent endometriosis and correlate the histologic findings with clinical appearance to expand sensitivity of the pathologic definition of endometriosis, particularly in patients on hormonal therapy. In all, 112 biopsies from 78 patients (mean age=25, range 18-39 yr) were reviewed for histopathologic features suggestive of or diagnostic for endometriosis including the presence of endometrial stroma, Müllerian epithelium, dystrophic calcifications, HLM, chronic inflammation, adhesions, and vascular proliferation. Endometriosis was confirmed by pathologic criteria in 37 of 78 patients (47%). Biopsies from patients on hormonal therapy (n=62, 80%) were significantly less likely to meet pathologic criteria for endometriosis (P=0.01). Nondiagnostic biopsies (70/112; 63%) frequently displayed HLM (20%), chronic inflammation (29%), dystrophic calcifications (26%), vascular proliferation (20%), or adhesions (20%) and were significantly more likely to have a vascular clinical appearance (P=0.01). Diagnostic biopsies (42/112; 38%) were more likely to have a blue/black clinical appearance (P=0.03), demonstrate HLM (P=0.004), and display pseudodecidualization (P=0.05). Patients with a high clinical suspicion of endometriosis have a range of histologic findings, with less than half meeting the current histopathologic criteria for diagnosing endometriosis. Given the heterogeneous histopathologic appearance, revision of the histologic criteria may be warranted with further exploration, particularly for lesions with predominantly vascular features.

    View details for DOI 10.1097/PGP.0000000000000743

    View details for PubMedID 33323857

  • Corrigendum to "Pathological chemotherapy response score is prognostic in tubo-ovarian high-grade serous carcinoma: A systematic review and meta-analysis of individual patient data" [Gynecol. Oncol. 154 (2019) 441-448]. Gynecologic oncology Cohen, P. A., Powell, A. n., Böhm, S. n., Gilks, C. B., Stewart, C. J., Meniawy, T. M., Bulsara, M. n., Avril, S. n., Brockbank, E. C., Bosse, T. n., de Azevedo Focchi, G. R., Ganesan, R. n., Glasspool, R. M., Howitt, B. E., Kim, H. S., Lee, J. Y., Le, N. D., Lockley, M. n., Manchanda, R. n., Mandalia, T. n., McCluggage, W. G., McNeish, I. n., Midha, D. n., Srinivasan, R. n., Tan, Y. Y., van der Griend, R. n., Yunokawa, M. n., Zannoni, G. F., Singh, N. n. 2020

    View details for DOI 10.1016/j.ygyno.2020.02.023

    View details for PubMedID 32087992

  • Germline mutations of SMARCA4 in small cell carcinoma of the ovary, hypercalcemic type and in SMARCA4-deficient undifferentiated uterine sarcoma: Clinical features of a single family and comparison of large cohorts. Gynecologic oncology Connor, Y. D., Miao, D., Lin, D. I., Hayne, C., Howitt, B. E., Dalrymple, J. L., DeLeonardis, K. R., Hacker, M. R., Esselen, K. M., Shea, M. 2019


    OBJECTIVE: Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) and SMARCA4-deficient undifferentiated uterine sarcoma (SMARCA4-DUS) are rare and aggressive tumors, primarily affecting pre- and perimenopausal women. Inactivating SMARCA4 mutations are thought to be the driving molecular events in the majority of these tumors. Here, we report the clinical course of a family with germline SMARCA4 mutation and compare large cohorts of these rare tumor types.METHODS: We extracted clinico-pathological medical record data for the family with germline SMARCA4 mutation. Clinico-genomic data from SCCOHT and SMARCA4-DUS cohorts were retrospectively extracted from the archives of a large CLIA-certified reference molecular laboratory.RESULTS: We identified a single family with an inherited germline SMARCA4 mutation, in which two different family members developed either SCCOHT or SMARCA4-DUS, both of whom died within one year of diagnosis, despite aggressive surgical, chemotherapy and immunotherapy treatment. Retrospective comparative analysis of large SCCOHT (n=48) and SMARCA4-DUS (n=17) cohorts revealed that SCCOHT patients were younger (median age: 28.5 vs. 49.0) and more likely to have germline SMARCA4 alterations (37.5% vs. 11.8%) than SMARCA4-DUS patients.CONCLUSIONS: Growing understanding of the role SMARCA4 plays in the pathogenesis of these rare cancers may inform recommended genetic testing and counseling in families with these tumor types.

    View details for DOI 10.1016/j.ygyno.2019.10.031

    View details for PubMedID 31954538

  • Targeted Genomic Profiling of Female Adnexal Tumors of Probable Wolffian Origin (FATWO) INTERNATIONAL JOURNAL OF GYNECOLOGICAL PATHOLOGY Mirkovic, J., Dong, F., Sholl, L. M., Garcia, E., Lindeman, N., MacConaill, L., Crum, C. P., Nucci, M. R., McCluggage, W., Howitt, B. E. 2019; 38 (6): 543–51
  • HPV 6-associated HSIL/Squamous Carcinoma in the Anogenital Tract INTERNATIONAL JOURNAL OF GYNECOLOGICAL PATHOLOGY Liu, M. Z., Hung, Y. P., Huang, E. C., Howitt, B. E., Nucci, M. R., Crum, C. P. 2019; 38 (5): 493–97
  • Evidence of a Monoclonal Origin for Bilateral Serous Tubal Intraepithelial Neoplasia INTERNATIONAL JOURNAL OF GYNECOLOGICAL PATHOLOGY Meserve, E. E., Strickland, K. C., Miron, A., Soong, T. R., Campbell, F., Howitt, B. E., Crum, C. P. 2019; 38 (5): 443–48
  • Pathological chemotherapy response score is prognostic in tubo-ovarian high-grade serous carcinoma: A systematic review and meta-analysis of individual patient data. Gynecologic oncology Cohen, P. A., Powell, A., Bohm, S., Gilks, C. B., Stewart, C. J., Meniawy, T. M., Bulsara, M., Avril, S., Brockbank, E. C., Bosse, T., de Azevedo Focchi, G. R., Ganesan, R., Glasspool, R. M., Howitt, B. E., Kim, H., Lee, J., Le, N. D., Lockley, M., Manchanda, R., Mandalia, T., McCluggage, W. G., McNeish, I., Midha, D., Srinivasan, R., Tan, Y. Y., van der Griend, R., Yunokawa, M., Zannoni, G. F., HGSC CRS Collaborative Network (Supplementary 1), Singh, N., Aggarwal, S., Bronger, H., Brown, E. B., Buck, M., Bukhari, S. A., Coghlan, E., Cope, N., de Almeida, M. S., De Kroon, C. D., Dean, A., Devlin, M., Ditzel, H. M., Drecoll, E., Fagotti, A., Faruqi, A., Feeney, L., Gupta, K., Harley, I., Inzani, F., Jeyarajah, A. R., Koay, M. H., Kroep, J. R., Lee, J., Leung, Y., Lockley, M., Loft, A. R., MaGee, D., Manchanda, R., McKenna, S., Midha, D., Millan, D., Millar, J., Miller, R., Mohan, G. R., Mughal, S., Nicolau, S. M., Nevin, J., Oakley, A. S., Quigley, M., Rai, B., Rajwanshi, A., Salfinger, S. G., Scambia, G., Scatchard, K., Schmalfeldt, B., Simcock, B., Singh, P., Strickland, K. C., Suri, V., Syed, S., Sykes, P., Tan, A., Tan, J., Thompson, E., Tinker, A. V., Trevisan, G., Uyeda, M. G., Vaughan, M. M., Weichert, W., Williams, A., Williams, S., Zorzato, P. C. 2019


    OBJECTIVE: There is a need to develop and validate biomarkers for treatment response and survival in tubo-ovarian high-grade serous carcinoma (HGSC). The chemotherapy response score (CRS) stratifies patients into complete/near-complete (CRS3), partial (CRS2), and no/minimal (CRS1) response after neoadjuvant chemotherapy (NACT). Our aim was to review current evidence to determine whether the CRS is prognostic in women with tubo-ovarian HGSC treated with NACT.METHODS: We established an international collaboration to conduct a systematic review and meta-analysis, pooling individual patient data from 16 sites in 11 countries. Patients had stage IIIC/IV HGSC, 3-4 NACT cycles and >6-months follow-up. Random effects models were used to derive combined odds ratios in the pooled population to investigate associations between CRS and progression free and overall survival (PFS and OS).RESULTS: 877 patients were included from published and unpublished studies. Median PFS and OS were 15 months (IQR 5-65) and 28 months (IQR 7-92) respectively. CRS3 was seen in 249 patients (28%). The pooled hazard ratios (HR) for PFS and OS for CRS3 versus CRS1/CRS2 were 0·55 (95% CI, 0·45-0·66; P < 0·001) and 0·65 (95% CI 0·50-0·85, P = 0·002) respectively; no heterogeneity was identified (PFS: Q = 6·42, P = 0·698, I2 = 0·0%; OS: Q = 6·89, P = 0·648, I2 = 0·0%). CRS was significantly associated with PFS and OS in multivariate models adjusting for age and stage. Of 306 patients with known germline BRCA1/2 status, those with BRCA1/2 mutations (n = 80) were more likely to achieve CRS3 (P = 0·027).CONCLUSIONS: CRS3 was significantly associated with improved PFS and OS compared to CRS1/2. This validation of CRS in a real-world setting demonstrates it to be a robust and reproducible biomarker with potential to be incorporated into therapeutic decision-making and clinical trial design.

    View details for DOI 10.1016/j.ygyno.2019.04.679

    View details for PubMedID 31118141

  • International Endocervical Adenocarcinoma Criteria and Classification (IECC): correlation with adverse clinicopathological features and patient outcome JOURNAL OF CLINICAL PATHOLOGY Hodgson, A., Olkhov-Mitsel, E., Howitt, B. E., Nucci, M. R., Parra-Herran, C. 2019; 72 (5): 347–53
  • Assessment of a Chemotherapy Response Score (CRS) System for Tubo-Ovarian High-Grade Serous Carcinoma (HGSC) INTERNATIONAL JOURNAL OF GYNECOLOGICAL PATHOLOGY Ditzel, H. M., Strickland, K. C., Meserve, E. E., Stover, E., Konstantinopoulos, P. A., Matulonis, U. A., Muto, M. G., Liu, J. F., Feltmate, C., Horowitz, N., Berkowitz, R. S., Gupta, M., Hecht, J. L., Lin, D. I., Jochumsen, K. M., Welch, W. R., Hirsch, M. S., Quade, B. J., Lee, K. R., Crum, C. P., Mutter, G. L., Nucci, M. R., Howitt, B. E. 2019; 38 (3): 230–40
  • Further Characterization of Classical Papillary Thyroid Carcinoma with "Hobnail-like" Features Chen, T., Wong, K., Higgins, S., Howitt, B., Barletta, J. NATURE PUBLISHING GROUP. 2019
  • A Combined Morphologic and Molecular Approach to Retrospectively Identify KRAS-Mutated Mesonephric-like Adenocarcinomas of the Endometrium AMERICAN JOURNAL OF SURGICAL PATHOLOGY Kolin, D. L., Costigan, D. C., Dong, F., Nucci, M. R., Howitt, B. E. 2019; 43 (3): 389-398
  • Evidence That "Precursor Escape" From the Distal Fallopian Tube is an Important Mechanism For High-Grade Serous Carcinogenesis Teschan, N., Soong, T., Pinto, A., Howitt, B., Nucci, M., Kolin, D., Crum, C. NATURE PUBLISHING GROUP. 2019
  • Comprehensive Morphological and Molecular Analyses Establish Germline BRCA-Associated Endometrial Carcinoma as a Distinct Entity de Jonge, M., Ritterhouse, L., de Kroon, C., Vreeswijk, M., Segal, J., Puranik, R., van Asperen, C., Smit, V., Howitt, B., Bosse, T. NATURE PUBLISHING GROUP. 2019
  • Comprehensive Morphological and Molecular Analyses Establish Germline BRCA-Associated Endometrial Carcinoma as a Distinct Entity de Jonge, M., Ritterhouse, L., de Kroon, C., Vreeswijk, M., Segal, J., Puranik, R., van Asperen, C., Smit, V., Howitt, B., Bosse, T. NATURE PUBLISHING GROUP. 2019
  • Evidence That "Precursor Escape" From the Distal Fallopian Tube is an Important Mechanism For High-Grade Serous Carcinogenesis Teschan, N., Soong, T., Pinto, A., Howitt, B., Nucci, M., Kolin, D., Crum, C. NATURE PUBLISHING GROUP. 2019
  • SMARCA4-Deficient Uterine Sarcoma and Undifferentiated Endometrial Carcinoma are Distinct Clinicopathologic Entities Kolin, D., Quick, C., Dong, F., Fletcher, C., Crum, C., Nucci, M., Howitt, B. NATURE PUBLISHING GROUP. 2019
  • Comprehensive Genomic Profiling of HPV-related and Gastric-type Endocervical Adenocarcinoma Parra-Herran, C., Hodgson, A., Lindeman, N., Howitt, B., Nucci, M. NATURE PUBLISHING GROUP. 2019
  • Comprehensive Genomic Profiling of HPV-related and Gastric-type Endocervical Adenocarcinoma Parra-Herran, C., Hodgson, A., Lindeman, N., Howitt, B., Nucci, M. NATURE PUBLISHING GROUP. 2019
  • SMARCA4-Deficient Uterine Sarcoma and Undifferentiated Endometrial Carcinoma are Distinct Clinicopathologic Entities Kolin, D., Quick, C., Dong, F., Fletcher, C., Crum, C., Nucci, M., Howitt, B. NATURE PUBLISHING GROUP. 2019
  • Clear Cell Renal Cell Carcinoma With a Poorly-Differentiated Component: A Novel Variant Causing Potential Diagnostic Difficulty Taneja, K., Cheng, L., Al-Obaidy, K., Kao, C., Barletta, J., Howitt, B., Wasco, M., Palanisamy, N., Gupta, N., Rogers, C., Carskadon, S., Chen, Y., Antic, T., Tretiakova, M., Williamson, S. NATURE PUBLISHING GROUP. 2019
  • Clear Cell Renal Cell Carcinoma With a Poorly-Differentiated Component: A Novel Variant Causing Potential Diagnostic Difficulty Taneja, K., Cheng, L., Al-Obaidy, K., Kao, C., Barletta, J., Howitt, B., Wasco, M., Palanisamy, N., Gupta, N., Rogers, C., Carskadon, S., Chen, Y., Antic, T., Tretiakova, M., Williamson, S. NATURE PUBLISHING GROUP. 2019
  • Further Characterization of Classical Papillary Thyroid Carcinoma with "Hobnail-like" Features Chen, T., Wong, K., Higgins, S., Howitt, B., Barletta, J. NATURE PUBLISHING GROUP. 2019
  • The fallopian tube, "precursor escape" and narrowing the knowledge gap to the origins of high-grade serous carcinoma GYNECOLOGIC ONCOLOGY Soong, T., Howitt, B. E., Horowitz, N., Nucci, M. R., Crum, C. P. 2019; 152 (2): 426-433
  • Clinicopathological and immunohistochemical features of uterine adenomyomatous polyps HUMAN PATHOLOGY Strickland, K. C., Yuan, L., Quade, B. J., Nucci, M. R., Howitt, B. E. 2019; 84: 239-245
  • Clinicopathologic and Immunohistochemical Correlates of CTNNB1 Mutated Endometrial Endometrioid Carcinoma. International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Costigan, D. C., Dong, F., Nucci, M. R., Howitt, B. E. 2019


    Endometrial endometrioid carcinomas (EECs) with exon 3 CTNNB1 mutations characterize a more aggressive subset of tumors in patients with low-grade low-stage disease. Thus, prospectively identifying these cases may be clinically relevant. The aim of this study was to examine the feasibility of beta-catenin and Cyclin D1 immunohistochemistry to identify EECs harboring CTNNB1 mutations and to evaluate the clinicopathologic features of EECs with exon 3 CTNNB1 mutations. Thirty-nine CTNNB1 mutated EECs and 40 CTNNB1 wild-type EECs were identified from a cohort of previously sequenced endometrial carcinomas using a targeted next-generation sequencing panel. Immunohistochemistry for beta-catenin and Cyclin D1 was performed on all cases. Immunohistochemistry results were correlated with CTNNB1 mutation status and clinicopathologic parameters. Patients with CTNNB1 mutated EECs were younger than those with CTNNB1 wild-type (56.2 vs. 61.5y; P=0.033). Nuclear beta-catenin expression correlated with exon 3 CTNNB1 mutation (P<0.0001) with a sensitivity of 91% and a specificity of 89%. Cyclin D1 expression correlated with CTNNB1 exon 3 mutation with relatively high specificity (90%) but low sensitivity (29%). Recurrence rate in patients with stage IA disease at diagnosis was significantly higher in patients whose tumors were CTNNB1 mutated compared with CTNNB1 wild-type (30% vs. 0%; P=0.025) and included distant metastases; all recurrent tumors in this group harbored exon 3 mutations and were histologically low grade (5 grade 1, 2 grade 2). Nuclear beta-catenin expression appears to be an acceptable proxy for CTNNB1 mutation.

    View details for PubMedID 30702464

  • International Endocervical Adenocarcinoma Criteria and Classification (IECC): correlation with adverse clinicopathological features and patient outcome. Journal of clinical pathology Hodgson, A., Olkhov-Mitsel, E., Howitt, B. E., Nucci, M. R., Parra-Herran, C. 2019


    AIMS: The International Endocervical Adenocarcinoma Criteria and Classification (IECC) was recently proposed as an improved method for categorising endocervical adenocarcinoma (EA) into human papillomavirus (HPV)-associated adenocarcinomas (HPVAs) and non-HPV-associated adenocarcinomas (NHPVAs). Such categorisation correlates with patient age and tumour size; however, its association with patient outcome remains to be established.METHODS: Institutional cases of EA with histological material available were selected. Three gynaecological pathologists independently classified all tumours according to the IECC with consensus review used when necessary. Clinicopathologic variables were recorded for each case.RESULTS: Of a total of 87 EAs, 71 (82%) were classified as HPVA and 16 (18%) as NHPVA. Among HPVA, most were usual type (51/71, 72%) followed by mucinous not otherwise specified (10/71, 14%) and invasive stratified mucin-producing carcinoma (ISMC, 8/71, 11%). Most NHPVAs were of gastric type (12/16, 71%) followed by clear cell and mesonephric (two each, 12%). Compared with HPVAs, NHPVAs were significantly associated with older age (p<0.001), larger horizontal extent (p=0.013), greater depth of invasion (p=0.003), lymphovascular space invasion (p<0.001), advanced stage (p<0.001) and invasive pattern C (p<0.001). On univariate analysis, worse disease-free survival (DFS) and disease-specific survival (DSS) correlated with NHPVA group. Among the HPVA subtypes, ISMC showed worse DFS and DSS compared with other HPVA types.CONCLUSIONS: The simple morphological approach of the IECC appears to be prognostically valuable. NHPVA (in particular gastric type) and ISMC (a recently recognised subset of HPVA) have an adverse outcome and their recognition following the IECC is important. We provide further evidence to replace the current WHO classification with the IECC.

    View details for PubMedID 30679193

  • Genomic Characterization of HPV-related and Gastric-type Endocervical Adenocarcinoma: Correlation With Subtype and Clinical Behavior. International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Hodgson, A. n., Howitt, B. E., Park, K. J., Lindeman, N. n., Nucci, M. R., Parra-Herran, C. n. 2019


    The majority of endocervical adenocarcinomas (EAs) are caused by human papillomavirus (HPV). Gastric-type EA, the second most common EA and unrelated to HPV, is biologically different with a more aggressive clinical course. Our knowledge of the molecular fingerprint of these important EA types and its role in diagnosis, prognosis and management is still evolving. Thus, we sought to evaluate the genomic profile of HPV-related and gastric EA. Clinical information including patient outcome was gathered for 56 tumors (45 HPV-associated and 11 gastric-type) surveying evaluated by a targeted massively parallel sequencing assay (OncoPanel platform) which surveys exonic DNA sequences of 447 cancer genes and 191 regions across 60 genes for rearrangement detection. KRAS, TP53, and PIK3CA were the most commonly mutated genes (10, 10, and 9 cases, respectively). Alterations in TP53, STK11, CDKN2A, ATM, and NTRK3 were significantly more common in gastric-type EA (P<0.05, Fisher exact test). Disease recurrence and/or death occurred in 14/49 (29%) cases with clinical information available (7 HPV-related (18% of HPV-related cases with clinical information available) and 7 gastric-type (64% of gastric-type cases with clinical information available). Tumors associated with adverse outcome, regardless of histotype, more commonly had alterations in KRAS (2 HPV-related, 4 gastric-type), GNAS (3 HPV-related, 1 gastric-type), and CDKN2A (0 HPV-related, 3 gastric type) compared with indolent-behaving cases (P<0.05, Fisher exact test). A total of 8/56 (14%) tumors harbored at least one actionable mutation; of these, 6 (75%) were associated with recurrence and/or cancer-related death. Copy number variations were detected in 45/56 cases (80%). The most frequent were chromosome 20 gain and 16q loss, identified in 7 cases each (all HPV-associated EA). The mutational profile of EA is diverse and correlates with clinical behavior and EA subtype. Thus, targeted sequencing assays can potentially serve as a diagnostic and prognostic tool. It can also identify targetable alterations, which may benefit patients with recurrent/metastatic disease.

    View details for DOI 10.1097/PGP.0000000000000665

    View details for PubMedID 31855952

  • International Society of Gynecological Pathologists (ISGyP) Endometrial Cancer Project: Guidelines From the Special Techniques and Ancillary Studies Group INTERNATIONAL JOURNAL OF GYNECOLOGICAL PATHOLOGY Cho, K. R., Cooper, K., Croce, S., Djordevic, B., Herrington, S., Howitt, B., Hui, P., Ip, P., Koebel, M., Lax, S., Quade, B. J., Shaw, P., Vidal, A., Yemelyanova, A., Clarke, B., Ellenson, L., Longacre, T. A., Shih, I., McCluggage, W., Malpica, A., Oliva, E., Parkash, V., Matias-Guiu, X. 2019; 38 (1): S114–S122
  • SMARCA4-deficient Uterine Sarcoma and Undifferentiated Endometrial Carcinoma are Distinct Clinicopathologic Entities. The American journal of surgical pathology Kolin, D. L., Quick, C. M., Dong, F. n., Fletcher, C. D., Stewart, C. J., Soma, A. n., Hornick, J. L., Nucci, M. R., Howitt, B. E. 2019


    Undifferentiated and dedifferentiated endometrial carcinomas (UDEC) are aggressive uterine tumors which may show loss of expression of SMARCA4 (BRG1) or SMARCB1 (INI-1). The recently described SMARCA4-deficient undifferentiated uterine sarcoma (SDUS) has a morphology which overlaps with UDEC. In this study, we compared clinical, morphologic, immunohistochemical, and molecular characteristics to identify features which differentiate SDUS from UDEC. Cases of SDUS (n=12) were compared with cases of UDEC (n=84, 55 of which were previously published). Immunohistochemistry was performed for p53, mismatch repair proteins, claudin-4, SMARCA4, and SMARCB1. Targeted molecular profiling was performed on 15 cases. Patients with SDUS were significantly younger than those with UDEC (mean 35.8 vs. 61.2 y, P=0.0001). UDEC and SDUS showed morphologic overlap; however, phyllodiform architecture favored a diagnosis of SDUS (36% vs. 0%, P=0.005), while prominent nuclear pleomorphism was only seen in some cases of UDEC (0% vs. 24%, P=0.15). Compared with SDUS, UDEC more frequently showed TP53 mutations (0% vs. 34%, P=0.03), microsatellite instability (0% vs. 44%, P=0.006), and intact SMARCA4 and SMARCB1 (0% vs. 80%); a panel combining these immunohistochemical markers had a sensitivity of 100% and specificity of 92% in distinguishing SDUS and UDEC. Cases of UDEC had mutations in genes associated with endometrial adenocarcinomas (eg, TP53, PTEN, PIK3CA) and occasionally SMARCA4, while SDUS was characterized solely by inactivating mutations in SMARCA4. Disease-specific survival was shorter in SDUS than UDEC (median survival 9 and 36 mo, P=0.01). In conclusion, SDUS occurs in younger patients than UDEC, has a worse prognosis, and in most cases has a distinct molecular and immunohistochemical profile.

    View details for DOI 10.1097/PAS.0000000000001375

    View details for PubMedID 31567195

  • A Potential Diagnostic Pitfall for Hobnail Variant of Papillary Thyroid Carcinoma. Histopathology Wong, K. S., Chen, T. Y., Higgins, S. E., Howitt, B. E., Lorch, J. H., Alexander, E. K., Marqusee, E. n., Cho, N. L., Nehs, M. A., Doherty, G. M., Barletta, J. A. 2019


    Hobnail variant of papillary thyroid carcinoma (PTC) is an aggressive PTC subtype characterized by a hobnail cytomorphology. However, some classic PTC have a "hobnail-like" cytomorphology associated with thick, hyalinized, variably edematous fibrovascular cores that appears to be a form of ischemic/degenerative atypia.We studied 3 cohorts to compare the histopathologic characteristics and clinical outcome of "hobnail-like" classic PTC and true hobnail variant of PTC: Cohort 1 - PTC consecutively resected between 2016-2017 (to assess frequency of "hobnail-like" cytomorphology); Cohort 2 - 20 "hobnail-like" classic PTC resected between 2005 and 2007 (to assess clinical outcome); Cohort 3 - seven true hobnail variant of PTC.A "hobnail-like" cytomorphology was identified in 16% of consecutively resected PTC. Compared with true hobnail variant, "hobnail-like" classic PTC occurred in younger patients (mean age 40 years versus 68 years, p<0.001), were smaller tumors (mean tumor size 2.1 cm versus 4.4 cm, p<0.001), had a lower rate of gross extrathyroidal extension (0% versus 71%, p<0.001), had a lower proliferative rate (>3 mitoses per 10 high power fields seen in 0% versus 71%, p<0.001; Ki67 index >5% in 0% versus 86%, p<0.001), a lower rate of secondary pathogenic mutations (for cases with molecular data, 0% versus 100%, p=0.0061), and improved survival (for cases with sufficient clinical outcome data, 10-year disease-free survival of 93% versus 0%, p=0.0016).Classic PTC can show ischemic/degenerative atypia that mimics the hobnail cytomorphology of true hobnail variant; however, these tumors lack aggressive histopathologic features and pursue an indolent clinical course.

    View details for DOI 10.1111/his.14042

    View details for PubMedID 31811787

  • International Endocervical Adenocarcinoma Criteria and Classification Validation and Interobserver Reproducibility AMERICAN JOURNAL OF SURGICAL PATHOLOGY Hodgson, A., Park, K. J., Djordjevic, B., Howitt, B. E., Nucci, M. R., Oliva, E., Stolnicu, S., Xu, B., Soslow, R. A., Parra-Herran, C. 2019; 43 (1): 75–83


    The current World Health Organization (WHO) classification for endocervical adenocarcinoma (EA) is based on descriptive morphologic characteristics; however, it does not fully reflect our current knowledge of the diverse pathogenesis of cervical glandular neoplasia. A novel classification system, the International Endocervical Adenocarcinoma Criteria and Classification (IECC), which incorporates etiology and biological behavior into the morphologic scheme, has been recently proposed. We aimed to validate the IECC by assessing its interobserver reproducibility in comparison to the WHO system. A cohort of 75 EAs was reviewed independently by 7 gynecologic pathologists and categorized following IECC and WHO criteria based on hematoxylin and eosin material alone and after immunohistochemistry results for p16, PR, p53, Napsin-A, vimentin, CDX2, and GATA3 were provided. Human papillomavirus (HPV) in situ hybridization and polymerase chain reaction results were compared with consensus diagnoses. IECC was superior to WHO in terms of interobserver agreement with κ=0.46 versus 0.3, respectively, on hematoxylin and eosin review and κ=0.51 versus 0.33, respectively, with immunohistochemistry. Under the IECC, 73 (97%) of EAs had majority agreement (≥4 reviewers in agreement) whereas 42 (56%) had perfect agreement (7/7 reviewers in agreement). Conversely, WHO showed majority agreement in 56 (75%) and perfect agreement in only 7 (10%) EAs. Reproducibility was poor in HPV-related WHO types (usual κ=0.36, mucinous not otherwise specified κ=0.13, intestinal κ=0.31, villoglandular κ=0.21) and good in major HPV-unrelated categories (gastric type κ=0.63, clear cell κ=0.81, mesonephric κ=0.5). Classification as per the IECC had excellent correlation with HPV status (by RNA in situ hybridization or polymerase chain reaction). We have shown that the IECC has superior interobserver agreement compared with the WHO classification system, and that distinction between HPV-related and HPV-unrelated EA can be made with good reproducibility and excellent prediction of HPV status. WHO morphologic variants of HPV-related EA are poorly reproducible. Conversely, agreement is high among important high-risk HPV-unrelated subtypes. Thus, our results further support replacing the current WHO classification with the IECC.

    View details for PubMedID 29877920

    View details for PubMedCentralID PMC6281796

  • Uterine Mesenchymal Tumors: Update on Classification, Staging, and Molecular Features. Surgical pathology clinics Parra-Herran, C. n., Howitt, B. E. 2019; 12 (2): 363–96


    The spectrum of mesenchymal neoplasia in the uterus has expanded in recent years. First, the identification of prevalent, recurrent molecular alterations has led to a more biologically and clinically congruent classification of endometrial stromal tumors. Likewise, the diagnostic criteria of several rare and miscellaneous tumor types have been refined in recent case series (Perivascular Epithelioid Cell tumor, inflammatory myofibroblastic tumor). Pure mesenchymal tumors are still broadly classified based on morphology according to the tumor cell phenotype. Smooth muscle tumors predominate in frequency, followed by tumors of endometrial stromal derivation; the latter are covered in depth in this article with an emphasis on defining molecular alterations and their morphologic and clinical correlates. The remaining entities comprise a miscellaneous group in which cell derivation does not have a normal counterpart in the uterus (eg, rhabdomyosarcoma) or is obscure (eg, undifferentiated uterine sarcoma). This article discusses their clinical relevance, recent insights into their molecular biology, and the most important differential diagnoses. Regarding the latter, immunohistochemistry and (increasingly) molecular diagnostics play a role in the diagnostic workup. We conclude with a few considerations on intraoperative consultation and macroscopic examination, as well as pathologic staging and grading of uterine sarcomas as per the most recent American Joint Cancer Commission and the Fédération Internationale de Gynécologie et d'Obstétrique staging systems.

    View details for DOI 10.1016/j.path.2019.01.004

    View details for PubMedID 31097109

  • Practical Issues and Updates in Gynecologic Pathology. Surgical pathology clinics Howitt, B. E. 2019; 12 (2): xi-xii

    View details for DOI 10.1016/j.path.2019.03.001

    View details for PubMedID 31097118

  • Germline BRCA-associated Endometrial Carcinoma is a Distinct Clinicopathologic Entity. Clinical cancer research : an official journal of the American Association for Cancer Research de Jonge, M. M., Ritterhouse, L. L., de Kroon, C. D., Vreeswijk, M. P., Segal, J. P., Puranik, R. n., Study, H. n., Hollema, H. n., Rookus, M. A., van Asperen, C. J., Van Leeuwen, F. E., Smit, V. T., Howitt, B. E., Bosse, T. n. 2019


    Whether endometrial cancer (EC) should be considered part of the gBRCA1/2-associated Hereditary Breast and Ovarian Cancer (HBOC)-syndrome is topic of debate. We sought to assess whether ECs occurring in gBRCA carriers are enriched for clinicopathologic and molecular characteristics, thereby supporting a causal relationship.Thirty-eight gBRCA carriers that developed EC were selected from the nationwide cohort study on Hereditary Breast and Ovarian Cancer in the Netherlands (HEBON), and these were supplemented with four institutional cases. Tumor tissue was retrieved via PALGA (Dutch Pathology Registry). Nineteen morphologic features were scored and histotype was determined by three expert gynecologic pathologists, blinded for molecular analyses (UCM-OncoPlus Assay including 1213 genes). ECs with LOH of the gBRCA- wildtype allele (gBRCA/LOHpos) were defined "gBRCA -associated", those without LOH (gBRCA/LOHneg) were defined 'sporadic'.LOH could be assessed for 40 ECs (30 gBRCA1, 10 gBRCA2 ), of which 60% were gBRCA/LOHpos. gBRCA/LOHpos ECs were more frequently of non-endometrioid (58%, P=0.001) and grade 3 histology (79%, P<0.001). All but two were in the TP53-mutated TCGA-subgroup (91.7%, P<0.001). In contrast, gBRCA/LOHneg ECs were mainly grade 1 endometrioid EC (94%) and showed a more heterogeneous distribution of TCGA-molecular subgroups: POLE-mutated (6.3%), MSI-high (25%), NSMP (62.5%) and TP53-mutated (6.3%).We provide novel evidence in favour of EC being part of the gBRCA-associated HBOC-syndrome. gBRCA-associated ECs are enriched for EC subtypes associated with unfavourable clinical outcome. These findings have profound therapeutic consequences as these patients may benefit from treatment strategies such as PARP-inhibitors. Additionally, it should influence counselling and surveillance of gBRCA carriers.

    View details for DOI 10.1158/1078-0432.CCR-19-0848

    View details for PubMedID 31492746

  • The fallopian tube, "precursor escape" and narrowing the knowledge gap to the origins of high-grade serous carcinoma. Gynecologic oncology Soong, T. R., Howitt, B. E., Horowitz, N., Nucci, M. R., Crum, C. P. 2018


    Most ovarian carcinomas are high-grade serous carcinomas (HGSC) that contain TP53 mutations, present at advanced stage, and eventually become resistant to chemotherapy. The rapid evolution of this disease has been attributed to an origin in the distal fallopian tube, in the form of serous tubal intraepithelial carcinomas (STICs). This has led to a disease model where malignancy develops first in the tube and spreads to the peritoneum or regional lymph nodes. However, although most early or incidentally discovered HGSCs manifest in the tube with STICs, many advanced HGSCs are not accompanied by a malignancy in the fimbria. To resolve this paradox, the focus has shifted to earlier, premalignant serous proliferations (ESPs) in the tubes, which lack the cytomorphologic features of malignancy but contain TP53 mutations. These have been termed p53 signatures or serous tubal intraepithelial lesions (STILs). Although they have not been presumed to have cancer-causing potential by themselves, some ESPs have recently been shown to share identical TP53 mutations with concurrent HGSCs, indicating a shared lineage between these early mucosal changes and metastatic malignancy. This discovery supports a paradigm by which HGSCs can emerge not only from STICs but also from exfoliated precursor cells (precursor escape) that eventually undergo malignant transformation within the peritoneal cavity. This paradigm unifies both localized and widespread HGSCs to a visible pre-existing cellular alteration in the tubal epithelium, and highlights a consistent and necessary biologic event (TP53 mutation) rarely encountered in the ovary or secondary Mullerian system. This dual pathway to HGSCs underscores the subtle nature of many serous cancer origins in the tube, explains contrasting clinico-pathologic presentations, and explains why, until recently, the fallopian tube was unappreciated as the principal origin of HGSCs. Moreover, it highlights additional challenges faced in preventing or intercepting HGSCs at a curable stage.

    View details for PubMedID 30503267

  • A Combined Morphologic and Molecular Approach to Retrospectively Identify KRAS-Mutated Mesonephric-like Adenocarcinomas of the Endometrium. The American journal of surgical pathology Kolin, D. L., Costigan, D. C., Dong, F., Nucci, M. R., Howitt, B. E. 2018


    An unusual subset of endometrial carcinoma, the mesonephric-like adenocarcinomas, are morphologically and molecularly similar to mesonephric carcinoma, characterized by KRAS mutation and lack of microsatellite instability. They also have a unique immunohistochemical profile and are usually positive for GATA-3, CD10, TTF-1, and negative for ER and PR. This study implemented a combined morphologic and molecular approach to retrospectively identify mesonephric-like carcinomas of the endometrium. KRAS-mutated microsatellite stable (MSS) endometrial carcinomas were identified from a database of 570 endometrial carcinomas that had undergone massively parallel sequencing. MSS tumors with canonical KRAS mutations that lacked features diagnostic of endometrioid carcinoma (including squamous or mucinous differentiation), were re-reviewed for morphologic features of mesonephric-like adenocarcinomas. Ninty-eight of 570 endometrial carcinomas (17%) harbored canonical KRAS mutations. Of the KRAS-mutated cases, 80 (82%) were MSS and 18 (18%) had microsatellite instability. Of the KRAS-mutated MSS cases with morphology review, 39/61 (64%) had squamous and/or mucinous differentiation while 22 (36%) lacked these histotype-defining features. Eight of these 22 had PTEN mutations and lacked morphologic features of mesonephric-like adenocarcinoma, leaving 14 cases with a possible mesonephric-like adenocarcinoma-like molecular profile that underwent detailed morphologic re-review. Ten of 14 had morphology typical of serous (3), carcinosarcoma (4), or endometrioid (3) carcinoma. In 4 cases, there was striking morphologic, immunophenotypic, and molecular resemblance to mesonephric carcinoma, leading to re-classification as mesonephric-like adenocarcinoma. Two of the 4 cases presented at an advanced stage, and a third case later developed distant metastases. On the basis of this retrospective study, KRAS-mutated mesonephric-like adenocarcinoma represents 1% of all endometrial carcinomas. Future prospective recognition of this unusual variant of endometrial carcinoma may be important given its possible aggressive nature.

    View details for PubMedID 30489318

  • Evidence for lineage continuity between early serous proliferations (ESPs) in the Fallopian tube and disseminated high-grade serous carcinomas JOURNAL OF PATHOLOGY Soong, T., Howitt, B. E., Miron, A., Horowitz, N. S., Campbell, F., Feltmate, C. M., Muto, M. G., Berkowitz, R. S., Nucci, M. R., Xian, W., Crum, C. P. 2018; 246 (3): 344–51


    The distal Fallopian tube is a site of origin for many 'ovarian' high-grade serous carcinomas (HGSCs) with intraepithelial carcinomas (STICs) that share identical TP53 mutations with metastatic tumors. TP53 mutation-positive early serous proliferations (ESPs) comprise a spectrum including p53 signatures and serous tubal intraepithelial lesions (STILs) and are not considered malignant; however, ESPs are often the only abnormality found in Fallopian tubes of women with metastatic HGSC. The purpose of this study was to determine if a relationship exists between isolated ESPs and concurrent metastatic HGSCs in the absence of STIC. Fallopian tubes from 32 HGSCs without a co-existing STIC/HGSC in the endosalpinx were exhaustively sectioned. The presence of either STIC/HGSC or ESP in the endosalpinx was documented and DNA from tissues containing ESPs, concurrent HGSC, and control epithelia were interrogated for TP53 mutations by targeted amplicon-based sequencing with average coverage reads >4000 across DNA replicate samples. Serial sectioning revealed a previously unrecognized STIC/HGSC in 3 of 32 (9.3%) and ESPs in 13 (40.6%). Twelve contained TP53 mutations. Nine (75%) shared identical TP53 mutations with concurrent HGSCs, four at high (≥ 5%) and five at low (< 5%) allele frequency. All control epithelia were TP53 mutation-negative. This study, for the first time, indicates lineage identity between ESPs in the distal tube and some metastatic HGSCs via a shared site-specific TP53 mutation. It supports a novel serous carcinogenic sequence in which an ESP could eventually culminate in a metastatic serous cancer via 'precursor escape' and would explain the apparent sudden onset of cancers without co-existing STICs. This paradigm for serous cancer development underscores the likelihood that multiple precursor types in the Fallopian tube contribute to serous cancer development with implications for the evolution, pathologic classification, and prevention of this lethal malignancy. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

    View details for PubMedID 30043522

  • PDGFB Rearrangements in Dermatofibrosarcoma Protuberans of the Vulva: A Study of 11 Cases Including Myxoid and Fibrosarcomatous Variants. International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Jahanseir, K., Xing, D., Greipp, P. T., Sukov, W. R., Keeney, G. L., Howitt, B. E., Schoolmeester, J. K. 2018; 37 (6): 537-546


    Dermatofibrosarcoma protuberans (DFSP) is a low-grade fibroblastic sarcoma that tends to arise in young to middle age adults and involve the trunk and proximal extremities. Rare examples of vulvar DFSP have been reported, including myxoid, myoid, and fibrosarcomatous variants, but detection of the characteristic t(17;22)(q22;q13) that produces COL1A1-PDGFB gene fusion has not been evaluated in a large series of primary vulvar tumors. The clinical, morphologic, immunohistochemical, and molecular cytogenetic features of 11 cases were examined. Patient age ranged from 29 to 75 yr (mean, 46 yr; median, 43 yr). Seven tumors were purely classic DFSP, 1 was purely myxoid DFSP and the remaining 3 had varying quantities of fibrosarcomatous DFSP. All cases of classic DFSP had diffuse expression of CD34 and low-level p53 immunoreactivity. Myxoid variants had strong, but reduced expression of CD34. Fibrosarcomatous DFSP showed focal CD34 expression and increased p53 reactivity. Nine of 11 tumors (82%) had rearrangement of PDGFB by fluorescence in situ hybridization. The 2 nonrearranged tumors were a classic DFSP and a myxoid DFSP with fibrosarcomatous transformation. Follow-up was available for 9 patients (82%) and ranged from 1 to 108 mo (mean, 30 mo; median, 21 mo). Eight patients had tumors with positive margins, one of which developed local recurrence after no further therapy. No patient developed metastasis. The high frequency of PDGFB rearrangement in vulvar DFSP provides a useful exploit in diagnostically challenging cases and genetic evidence of probable clinical response to targeted therapeutics in cases of locally advanced or metastatic tumors.

    View details for DOI 10.1097/PGP.0000000000000472

    View details for PubMedID 29140881

    View details for PubMedCentralID PMC5951727

  • Clinicopathologic and Immunohistochemical features of uterine Adenomyomatous polyps. Human pathology Strickland, K. C., Yuan, L., Quade, B. J., Nucci, M. R., Howitt, B. E. 2018


    Adenomyomatous polyps (APs) of the uterus (also termed polypoid adenomyomas and pedunculated adenomyomas) are exophytic proliferations composed of myomatous stroma admixed with endometrial glands. APs can be diagnostically challenging, mimicking polypoid neoplasms such as atypical polypoid adenomyoma and adenosarcoma. The purpose of this study was to describe the clinicopathologic, morphologic, and molecular features of APs, as well as to raise awareness of this entity as a potential source of diagnostic confusion. We identified APs diagnosed at Brigham and Women's Hospital from 2000 to 2015. We reviewed histologic slides and obtained archival tissue for immunohistochemical and molecular studies. APs seen in consultation were associated with a broad differential, including adenosarcoma, atypical polypoid adenomyoma, and endometrial neoplasia. We performed a histologic review of 84 APs diagnosed at our institution and identified two distinct morphologic types of APs, which we have termed type 1 (with vaguely fascicular myomatous stroma intimately admixed with glands) and type 2 (containing a well-defined stalk of smooth muscle entrapping glands). The majority of APs exhibited CD10 (100%, 72/72) and desmin (97%, 70/72) positive stroma. Diffuse caldesmon positivity was present in 97% (28/29) type 2 polyps, compared to 8% (3/39) of type 1 APs. APs did not harbor mutations in exon 2 of MED12. APs are not uncommon in routine practice and may be misinterpreted as more worrisome lesions. We identified two types of APs with distinct morphology and immunophenotype. The absence of MED12 exon 2 mutations suggests that the pathogenesis of APs is separate from uterine leiomyomas.

    View details for PubMedID 30339971

  • HPV 6-associated HSIL/Squamous Carcinoma in the Anogenital Tract. International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Liu, M. Z., Hung, Y. P., Huang, E. C., Howitt, B. E., Nucci, M. R., Crum, C. P. 2018


    Human papillomavirus (HPV) type 6 is historically classified as low-risk HPV type and associates with low-grade squamous intraepithelial lesions of the anogenital tract. Rare squamous carcinomas have been reported in association with these HPV types but the mechanism(s) behind this carcinogenic sequence have been unclear. We report 4 cases of low risk anogenital HPV infections-3 cervical (immature low-grade squamous intraepithelial lesion with metaplastic phenotype) and one anal (exophytic condyloma) lesion-that manifested with high-grade squamous intraepithelial lesion/squamous cell carcinoma. Two were associated with invasion one of which metastasized to a regional node. Two cases exhibited strong p53 positivity in the high-grade squamous intraepithelial lesion/squamous cell carcinoma component analogous to that seen in HPV-negative differentiated intraepithelial lesions of the external genitalia. This series of cases adds to the literature on low risk HPV-associated cervical squamous carcinomas. It underscores the similarities between the baseline cyto-morphology and benign mimics (low-grade squamous intraepithelial lesions), the subtle cytologic and immunohistochemical (MIB1) features heralding biologic aggressiveness, and in some potential pathways (p53) not usually involved in HPV-related anogenital neoplasia.

    View details for PubMedID 30312218

  • Inter-pathologist and pathology report agreement for ovarian tumor characteristics in the Nurses' Health Studies GYNECOLOGIC ONCOLOGY Barnard, M. E., Pyden, A., Rice, M. S., Linares, M., Tworoger, S. S., Howitt, B. E., Meserve, E. E., Hecht, J. L. 2018; 150 (3): 521–26


    Grade and histotype of ovarian carcinomas are often used as surrogates of molecular subtypes. We examined factors affecting pathologists' reproducibility in two prospective studies.Two pathologists independently reviewed slides from 459 incident ovarian cancers in the Nurses' Health Study (NHS) and NHSII. We described agreement on tumor characteristics using percent agreement and Cohen's standard kappa (κ) coefficients. We used logistic regression, with disagreement as the outcome, to evaluate the contribution of case and tumor characteristics to agreement.Inter-rater agreement was 95% (κ = 0.81) for carcinoma versus borderline, 89% (κ = 0.58) for grade and 85% (κ = 0.71) for histotype. Inter-rater grading disagreement was higher for non-serous histotypes (OR = 4.66, 95% CI 2.09-10.36) and lower for cancers with bizarre atypia (OR = 0.13, 95% CI 0.04-0.38). Agreement with original pathology reports was 94% (κ = 0.73) for carcinoma versus borderline, 78% (κ = 0.60) for histotype, and 79% (κ = 0.24) for grade. Grading disagreement was significantly lower for tumors with 'solid, pseudoendometrioid or transitional' (SET) architecture (OR = 0.08, 95%CI 0.01-0.84). Date of original diagnosis, hospital type, number of slides available for review, tumor stage, and slide quality were not related to agreement.Overall, inter-rater agreement for tumor type and grade for archival tissue specimens was good. Agreement between the consensus review and original pathology reports was lower. Factors contributing to grading disagreement included non-serous histotype, absence of bizarre atypia, and absence of SET architecture.

    View details for PubMedID 30001835

    View details for PubMedCentralID PMC6102072

  • SMARCA4-deficient undifferentiated uterine sarcoma (malignant rhabdoid tumor of the uterus): a clinicopathologic entity distinct from undifferentiated carcinoma MODERN PATHOLOGY Kolin, D. L., Dong, F., Baltay, M., Lindeman, N., MacConaill, L., Nucci, M. R., Crum, C. P., Howitt, B. E. 2018; 31 (9): 1442–56


    Small cell carcinoma of the ovary, hypercalcemic type is a rare, aggressive malignancy which usually occurs in young women and is characterized by mutations in SMARCA4, with few other alterations. We recently encountered uterine tumors with morphologic, immunohistochemical, and genetic similarities to small cell carcinoma of the ovary, hypercalcemic type. Herein we report the clinicopathologic and molecular features (using a targeted massively parallel sequencing [MPS] assay) of these tumors. The cases were diagnosed on cervical and endometrial biopsies (n = 2, 34, and 29 years) or hysterectomy and bilateral salpingo-oophorectomy (n = 3, 25, 33, and 58 years). The tumors were composed of sheets of large atypical epithelioid cells with prominent rhabdoid morphology, indistinguishable from the "large cell" variant of small cell carcinoma of the ovary, hypercalcemic type. In three cases, the ovaries were pathologically examined to exclude a primary ovarian malignancy. Immunohistochemically, four of four cases showed SMARCA4 loss, and were negative or only focally positive for keratins, EMA, and claudin-4. One of three cases was positive for WT-1. Targeted MPS was successfully performed on 4 of 5 tumors, and showed recurrent mutations in SMARCA4, with few other alterations. Of the cases diagnosed on hysterectomy, all had extensive lymphovascular invasion, extra-uterine spread, and marked infiltrative growth. These tumors were uniformly aggressive; all patients died of disease (median survival 7 months, range 1-43 months). We propose this entity be called "SMARCA4-deficient undifferentiated uterine sarcoma (malignant rhabdoid tumor of the uterus)", a term which describes both the tumor's underlying molecular abnormality and its morphology. Its unique clinicopathologic and molecular features differentiate it from other related malignancies, including undifferentiated endometrial carcinoma, small cell carcinoma of the ovary (hypercalcemic type), and epithelioid sarcoma. We review and discuss previously reported "rhabdoid tumors of the uterus;" while they are a heterogenous group of tumors, some of them are likely examples of this entity. Correctly identifying cases of SMARCA4-deficient uterine sarcoma from histologic mimics is important as it may have prognostic, predictive, and germline implications.

    View details for PubMedID 29700418

  • Targeted Genomic Profiling of Female Adnexal Tumors of Probable Wolffian Origin (FATWO). International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Mirkovic, J., Dong, F., Sholl, L. M., Garcia, E., Lindeman, N., MacConaill, L., Crum, C. P., Nucci, M. R., McCluggage, W. G., Howitt, B. E. 2018


    Female adnexal tumor of probable Wolffian origin (FATWO) is a rare gynecologic neoplasm of low-malignant potential presumed to be derived from mesonephric remnants in the upper female genital tract. Similarly, mesonephric remnants in the lower female genital tract are thought to be the origin for mesonephric carcinoma. Although the molecular alterations in mesonephric carcinoma have been recently reported, the pathogenesis of and molecular alterations in FATWO are not well understood. The aims of this study were to examine the molecular alterations in FATWO and to establish whether these neoplasms are molecularly similar to mesonephric carcinoma. Eight FATWOs underwent massively parallel sequencing to detect single nucleotide variations, copy number variations, and structural variants by surveying exonic DNA sequences of 300 cancer genes and 113 introns across 35 genes. Good quality DNA was isolated from 7 of 8 cases. Novel KMT2D variants (1 frameshift, 3 missense) were identified in 4 of 7 cases (57%), but were variants of uncertain biologic significance. STK11 mutations (both frameshift) were identified in 2 of 7 cases (29%); one of these was in a patient with a known history of Peutz-Jeghers syndrome. A mutation in the chromatin remodeling gene ARID1B was identified in 1 of 7 cases (14%). No cases harbored KRAS, NRAS, TP53, PIK3CA, PTEN, or DICER1 mutations. There were relatively low numbers of copy number variations, and no recurrent copy number variations were identified. One case demonstrated moderate copy gain of CCND1. No structural variants were identified. In summary, FATWO is characterized molecularly by the absence of KRAS/NRAS mutations (characteristic of mesonephric carcinoma), absence of DICER1 mutations (characteristic of Sertoli-Leydig cell tumor) and frequent KMT2D mutations of unknown biologic significance. FATWOs exhibit a limited number of molecular aberrations that are significantly different from those reported in tumors in the differential diagnosis, and our results question the relationship of mesonephric carcinoma with FATWO. Disease-defining molecular alterations for FATWO have yet to be discovered.

    View details for PubMedID 30134342

  • Evidence of a Monoclonal Origin for Bilateral Serous Tubal Intraepithelial Neoplasia. International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Meserve, E. E., Strickland, K. C., Miron, A., Soong, T. R., Campbell, F., Howitt, B. E., Crum, C. P. 2018


    Serous tubal intraepithelial carcinoma (STIC) is found in 10% to 60% of cases of tuboovarian high-grade serous carcinoma (HGSC) and is presumed to be the site of origin, linking many HGSCs to the fallopian tube. Bilateral STIC is present in 20% of cases. Because clonal Tp53 mutations are a defining feature of HGSC, including their associated STICs, we analyzed 4 cases of bilateral serous tubal intraepithelial neoplasia (STIN), including STIC and Tp53-mutated serous tubal intraepithelial lesions (STILs), associated with HGSC to determine whether they contained the same or different p53 mutations. Extracted DNA from STINs, concurrent HGSCs and control tissues was analyzed for mutations in all exons of Tp53. Sequencing was successful in 3 of the 4 cases, and an identical Tp53 mutation was detected in the HGSC and bilateral STINs in 2 of these 3 cases. One STIN was morphologically a STIL. These findings confirm that a subset of bilateral STINs share the same Tp53 mutation, implying that at least one of the STINs is an intraepithelial metastasis from either the contralateral STIN or HGSC. This study complements others addressing the multiple origins of STIN in the setting of existing HGSC. It further underscores the fact that potential overlap in biologic behavior between STILs and STICs as well as timing and direction of metastatic spread has yet to be resolved.

    View details for PubMedID 29901519

  • Assessment of a Chemotherapy Response Score (CRS) System for Tubo-Ovarian High-Grade Serous Carcinoma (HGSC). International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Ditzel, H. M., Strickland, K. C., Meserve, E. E., Stover, E., Konstantinopoulos, P. A., Matulonis, U. A., Muto, M. G., Liu, J. F., Feltmate, C., Horowitz, N., Berkowitz, R. S., Gupta, M., Hecht, J. L., Lin, D. I., Jochumsen, K. M., Welch, W. R., Hirsch, M. S., Quade, B. J., Lee, K. R., Crum, C. P., Mutter, G. L., Nucci, M. R., Howitt, B. E. 2018


    A chemotherapy response score (CRS) system was recently described to assess the histopathologic response and prognosis of patients with tubo-ovarian high-grade serous carcinoma (HGSC) receiving neoadjuvant chemotherapy. The current study was performed as an independent assessment of this CRS system. We retrospectively identified advanced stage HGSC patients who received neoadjuvant chemotherapy and underwent interval debulking. If available, a hemotoxylin and eosin slide from the omentum and the adnexa was selected for the study. Slides were independently scored by 13 pathologists using the 3-tiered CRS system. Reviewers then received web-based training and rescored the slides. Overall survival and progression-free survival were estimated using the Kaplan-Meier method and compared using the log-rank test. A total of 68 patients with omental (n=65) and/or adnexal (n=59) slides were included in the study. Interobserver reproducibility was moderate for omentum (kappa, 0.48) and poor for adnexa (kappa, 0.40), which improved for omentum (kappa, 0.62) but not for adnexa (kappa, 0.38) after online training. For omental slides, a consensus CRS of 1/2 was associated with a shorter median progression-free survival (10.9mo; 95% confidence interval, 9-14) than a CRS of 3 (18.9mo; 95% CI, 18-24; P=0.020). In summary, a 3-tiered CRS system of hemotoxylin and eosin-stained omental deposits can yield prognostic information for HGSC patients receiving neoadjuvant chemotherapy, and web-based training improved reproducibility but did not alter determination of clinical outcomes. The CRS system may allow oncologists to identify potential nonresponders and triage HGSC patients for heightened observation and/or clinical trials.

    View details for PubMedID 29750700

  • Reasons Associated with Total Thyroidectomy as Initial Surgical Management of an Indeterminate Thyroid Nodule ANNALS OF SURGICAL ONCOLOGY Angell, T. E., Vyas, C. M., Barletta, J. A., Cibas, E. S., Cho, N. L., Doherty, G. M., Gawande, A. A., Howitt, B. E., Krane, J. F., Marqusee, E., Strickland, K. C., Alexander, E. K., Moore, F. D., Nehs, M. A. 2018; 25 (5): 1410-1417


    Diagnostic hemithyroidectomy (HT) is the most widely recommended surgical procedure for a nodule with indeterminate cytology; however, additional details may make initial total thyroidectomy (TT) preferable. We sought to identify patient-specific factors (PSFs) associated with initial TT in patients with indeterminate thyroid nodules.Retrospective analysis of all patients with a thyroid nodule ≥ 1 cm and initial cytology of atypia of undetermined significance or suspicious for follicular neoplasm between 2012 and 2015 who underwent thyroidectomy. Medical records were reviewed for patient demographics, neck symptoms, nodule size, cytology, molecular test results, final histopathology, and additional PSFs influencing surgical management. Variables were analyzed to determine associations with the use of initial TT. Logistic regression analyses were performed to identify independent associations.Of 325 included patients, 182/325 (56.0%) had HT and 143/325 (44.0%) had TT. While patient age and sex, nodule size, and cytology result were not associated with initial treatment, five PSFs were associated with initial TT (p < 0.0001). These included contralateral nodules, hypothyroidism, fluorodeoxyglucose avidity on positron emission tomography scan, family history of thyroid cancer, and increased surgical risk. At least one PSF was present in 126/143 (88.1%) TT patients versus 47/182 (25.8%) HT patients (p < 0.0001). Multivariate logistic regression analysis demonstrated that these variables were the strongest independent predictor of TT (odds ratio 45.93, 95% confidence interval 18.80-112.23, p < 0.001).When surgical management of an indeterminate cytology thyroid nodule was performed, several PSFs were associated with a preference by surgeons and patients for initial TT, which may be useful to consider in making decisions on initial operative extent.

    View details for DOI 10.1245/s10434-018-6421-x

    View details for Web of Science ID 000429536700044

    View details for PubMedID 29520656

  • Solitary fibrous tumour of the female genital tract: a clinicopathological analysis of 25 cases HISTOPATHOLOGY Yang, E. J., Howitt, B. E., Fletcher, C. M., Nucci, M. R. 2018; 72 (5): 749–59


    Solitary fibrous tumour (SFT) is an uncommon spindle cell neoplasm of fibroblastic origin, first described as a tumour of the pleura and now well established at extrapleural sites. However, SFT in the female genital tract is rare and therefore not fully characterised. Here, we describe a series of 25 SFTs arising throughout the gynaecological tract, including the vulva (14 cases), vagina (one), cervix (one), uterus (six), ovary (two), and fallopian tube (one).The tumours showed classic histology as well as known variant morphological features, including a fatty component, diffuse stromal hyalinisation, myxoid stroma, and giant-cell angiofibroma-like features. Eleven (11/25, 44%) were considered to be histologically malignant on the basis of mitotic counts of ≥4 per 10 high-power fields. Follow-up data were available for nine (3-56 months; mean 25 months). Six patients are alive with no evidence of disease, and three are alive with disease. Both SFT and other spindle cell lesions of the gynaecological tract were stained for STAT6. Ninety per cent of SFTs showed nuclear expression of STAT6. The majority of other tumour types were negative for STAT6, except for a subset of inflammatory myofibroblastic tumours (1/3; 33%), fibroma/thecoma (3/56; 5%), and sclerosing stromal tumour (1/3; 33%), which showed weak/focal staining.Gynaecological SFT can be diagnosed reliably with careful morphological evaluation and judicious use of immunohistochemical stains, and should be considered in the diagnostic workup of spindle cell tumours of unclear lineage in the female genital tract.

    View details for PubMedID 29106748

  • Insurance status and cancer treatment mediate the association between race/ethnicity and cervical cancer survival PLOS ONE Markt, S. C., Tang, T., Cronin, A. M., Katz, I. T., Howitt, B. E., Horowitz, N. S., Lee, L. J., Wright, A. A. 2018; 13 (2): e0193047


    Cervical cancer outcomes remain poor among disadvantaged populations, including ethnic minorities, low-income, and underinsured women. The aim of this study was to evaluate the mechanisms that underlie the observed association between race/ethnicity and cervical cancer survival. We identified 13,698 women, ages 21 to 64 years, diagnosed with stages I-III primary cervical cancer between 2007-2013 in Surveillance, Epidemiology, and End Results (SEER). Multivariable Cox proportional hazards regression models evaluated associations between race/ethnicity (Non-Hispanic White, Non-Hispanic Black, Hispanic, Other) and cervical cancer-specific mortality. We conducted mediation analysis to calculate the mediation proportion and its 95% confidence interval. Non-Hispanic black women had an increased risk of cervical cancer-specific mortality (HR: 1.23, 95% CI: 1.08-1.39), and Hispanic women a decreased risk of dying from their disease (HR: 0.82, 95% CI: 0.72-0.93), compared with non-Hispanic white. The estimated proportion of excess cervical cancer mortality for non-Hispanic black women relative to non-Hispanic white women that was mediated by insurance was 18.6% and by treatment was 47.2%. Furthermore, non-Hispanic black women were more likely to receive radiation and less likely to receive surgery for early-stage disease. In this population-based study we found that some of the excess cervical cancer-specific mortality for non-Hispanic black women is mediated by factors such as insurance status and treatment. These findings suggest that enhancing existing insurance coverage and ensuring equal and adequate treatment in all women may be a key strategy for improving cervical cancer outcomes.

    View details for DOI 10.1371/journal.pone.0193047

    View details for Web of Science ID 000425283900102

    View details for PubMedID 29447263

    View details for PubMedCentralID PMC5814056

  • Mesonephric proliferations of the female genital tract PATHOLOGY Howitt, B. E., Nucci, M. R. 2018; 50 (2): 141–50


    The mesonephric (Wolffian) duct regresses in females during embryological development. Remnants of this duct may persist typically along the lateral walls of the cervix, vagina, adnexa, and uterine corpus. These mesonephric epithelia may expand into hyperplastic proliferations and rarely form neoplasms. The spectrum of morphology, immunophenotype, clinical presentation, and molecular characteristics of mesonephric lesions is reviewed, with attention to distinction from entities in the differential diagnosis.

    View details for DOI 10.1016/j.pathol.2017.11.084

    View details for Web of Science ID 000426351600004

    View details for PubMedID 29269124

  • Targeted Genomic Profiling Reveals Recurrent KRAS Mutations in Mesonephric-like Adenocarcinomas of the Female Genital Tract. The American journal of surgical pathology Mirkovic, J., McFarland, M., Garcia, E., Sholl, L. M., Lindeman, N., MacConaill, L., Dong, F., Hirsch, M., Nucci, M. R., Quick, C. M., Crum, C. P., McCluggage, W. G., Howitt, B. E. 2018; 42 (2): 227-233


    Mesonephric adenocarcinoma most commonly arises in the cervix and is presumed to be derived from normal or hyperplastic mesonephric remnants. It is characterized by recurrent KRAS mutations and lack of PIK3CA/PTEN alterations. Adenocarcinomas of the uterine corpus and ovary characterized by morphologic and immunophenotypic similarities to mesonephric adenocarcinoma have been reported. The pathogenesis of these tumors, which have been designated "mesonephric-like adenocarcinomas" is unknown, and it has been debated whether these represent mesonephric adenocarcinomas that arise in the endometrium/ovary or endometrioid adenocarcinomas that closely mimic mesonephric adenocarcinoma. The relationship at the molecular level between mesonephric adenocarcinomas and mesonephric-like adenocarcinomas is unknown. The aim of this study was to examine the molecular alterations in mesonephric-like adenocarcinomas to identify driver mutations and potential therapeutically targetable mutations, and to determine the relationship between mesonephric-like adenocarcinomas and mesonephric adenocarcinomas using targeted next-generation sequencing. Seven mesonephric-like adenocarcinomas (4 ovarian, 3 uterine corpus) underwent targeted next-generation sequencing to detect mutations, copy number variations and structural variants in exonic regions of 300 cancer genes, and 113 selected intronic regions across 35 genes. All 7 tumors (100%) harbored canonical activating KRAS mutations (4 G12D, 3 G12V). PIK3CA activating mutations were identified in 3 of 7 (43%) cases. There were no alterations in PTEN, ARID1A, or TP53 in any of the tumors. In copy number analysis, 5 of 7 (71%) tumors exhibited 1q gain, which was accompanied by 1p loss in 2 cases. In addition, 4 of 7 (57%) tumors had chromosome 10 gain, which was accompanied by gain of chromosome 12 in 3 cases. Mesonephric-like adenocarcinomas, similar to mesonephric adenocarcinomas, are characterized by recurrent KRAS mutations, gain of 1q, lack of PTEN mutations, and gains of chromosomes 10 and 12. PIK3CA mutations, which have not previously been identified in mesonephric adenocarcinoma, were found in 3 of 7 (43%) mesonephric-like adenocarcinomas in our study. Mesonephric-like adenocarcinomas exhibit strikingly similar molecular aberrations to mesonephric adenocarcinomas, but also frequently harbor PIK3CA mutations, demonstrating biological overlap with carcinomas of both mesonephric and Mullerian (endometrioid) differentiation. Given the previously documented association with endometriosis (ovarian neoplasms) and the prominent endometrial involvement (uterine corpus neoplasms), we believe these are best regarded as of Mullerian origin and representing adenocarcinomas which differentiate along mesonephric lines; as such, we propose the term mesonephric-like Mullerian adenocarcinoma.

    View details for DOI 10.1097/PAS.0000000000000958

    View details for PubMedID 28984674

  • WITHDRAWN: International Society of Gynecological Pathologists (ISGyP) Endometrial Cancer Project: Guidelines From the Special Techniques and Ancillary Studies Group. International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Cho, K. R., Cooper, K., Croce, S., Djordevic, B., Herrington, S., Howitt, B., Hui, P., Ip, P., Koebel, M., Lax, S., Quade, B. J., Shaw, P., Vidal, A., Yemelyanova, A., Clarke, B., Hedrick Ellenson, L., Longacre, T. A., Shih, I., McCluggage, W. G., Malpica, A., Oliva, E., Parkash, V., Matias-Guiu, X. 2018


    Ahead of Print article withdrawn by publisher.

    View details for PubMedID 29521846

  • Criteria for Risk Stratification of Vulvar and Vaginal Smooth Muscle Tumors An Evaluation of 71 Cases Comparing Proposed Classification Systems AMERICAN JOURNAL OF SURGICAL PATHOLOGY Sayeed, S., Xing, D., Jenkins, S. M., Weisman, P. S., Buehler, D., Warmke, L., Uram-Tuculescu, C., Bakkum-Gamez, J. N., Howitt, B. E., Cortese, C., Park, K. J., Schoolmeester, J. 2018; 42 (1): 84-94


    Accurate risk stratification of smooth muscle tumors (SMTs) is essential for appropriate patient management. Yet, the rarity of SMTs of the vagina and vulva makes development of a prognostically meaningful classification system challenging. While 2 classification methods for vulvar SMTs and 1 for vaginal SMTs have been proposed, it is our experience that many pathologists tend to apply criteria for uterine SMTs when evaluating vulvovaginal tumors. We retrospectively reviewed a large cohort of vulvovaginal SMTs with clinical follow-up and evaluated which method most accurately classified tumors according to patient outcome. A total of 71 tumors, 53 vaginal (75%) and 18 vulvar (25%), from 71 patients were identified. All tumors were centrally examined for degree of cytologic atypia, morphology (spindled, epithelioid, myxoid), mitotic index per 10 high power fields, atypical mitotic figures, tumor cell necrosis, ischemic necrosis, tumor interface (circumscribed or infiltrative) and margin status. Clinical features were recorded for each patient. Follow-up was available for 63 patients (89%), and ranged from 1 to 234 months (median: 64 mo). While site-specific and uterine criteria showed equally excellent sensitivity in classifying smooth muscle neoplasms as leiomyosarcoma according to patient outcome, uterine criteria showed improved specificity relatively to site-specific methods in classifying tumors as nonsarcoma according to patient outcome. We recommend that uterine SMT criteria and nomenclature be adopted for evaluation and classification of vulvovaginal SMTs.

    View details for DOI 10.1097/PAS.0000000000000920

    View details for Web of Science ID 000418722200011

    View details for PubMedID 28786880

    View details for PubMedCentralID PMC5730467

  • Pleomorphic fibroma of the skin with MDM2 immunoreactivity: A potential diagnostic pitfall JOURNAL OF CUTANEOUS PATHOLOGY Tashakori, M., Pimentel, J., Howitt, B. E., Sanchez, J., Michalowski, S., Chitale, D., Ormsby, A. H., Williamson, S. R. 2018; 45 (1): 59-62


    Pleomorphic fibroma is a rare benign cutaneous neoplasm characterized by spindle-shaped cells and multinucleated giant cells scattered throughout collagenous stroma. These morphologic features can lead to diagnostic confusion, including atypical lipomatous tumor as one consideration. In contrast to atypical lipomatous tumor, previous studies have found pleomorphic fibroma to be negative for MDM2 immunohistochemical staining and MDM2 gene amplification. Here, we present a case of pleomorphic fibroma of skin with nuclear MDM2 immunoreactivity in the absence of MDM2 gene amplification, underscoring the superiority of fluorescence in situ hybridization as a diagnostic test in this differential diagnosis. The RB1 locus is also explored for differential diagnosis with pleomorphic/spindle cell lipoma and related entities.

    View details for DOI 10.1111/cup.13052

    View details for Web of Science ID 000418410900010

    View details for PubMedID 28981153

  • Targeted next-generation sequencing in the detection of mismatch repair deficiency in endometrial cancers. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc Dong, F. n., Costigan, D. C., Howitt, B. E. 2018


    Mismatch repair deficiency represents a biomarker of immunotherapy response and a phenotypic feature of Lynch syndrome-associated endometrial cancers. Using a targeted next-generation sequencing assay, we identified molecular features of mismatch repair deficiency, specifically insertion and deletion mutations in mononucleotide repeats, and established thresholds for the number of such mutations to classify endometrial cancers as mismatch repair deficient, proficient, or indeterminate. Sequencing classification was compared to the loss of MLH1, MSH2, MSH6, or PMS2 expression by immunohistochemistry. A total of 259 endometrial cancers were classified by sequencing as mismatch repair deficient (n = 48, 19%), proficient (n = 199, 77%), or indeterminate (n = 12, 5%). Sequencing findings were concordant with loss of expression of at least one mismatch repair protein in 47 of 48 (98%) cases classified as deficient and retained expression of all four proteins in 190 of 199 (95%) cases classified as proficient. Of the 12 cases classified as indeterminate, 7 (58%) demonstrated mismatch repair protein loss. Overall, targeted next-generation sequencing exhibited a high rate of concordance with immunohistochemistry for mismatch repair deficiency; however, sequencing was indeterminate in a few cases and demonstrated a false negative rate of 5%. Although we recommend implementation of a mismatch repair deficiency algorithm for laboratories performing next-generation sequencing cancer panels, immunohistochemistry remains a cost-effective screening method for mismatch repair deficiency in endometrial cancer.

    View details for PubMedID 30206407

  • Cervical mesonephric hyperplasia lacks KRAS/NRAS mutations. Histopathology Mirkovic, J., Schoolmeester, J. K., Campbell, F., Miron, A., Nucci, M. R., Howitt, B. E. 2017; 71 (6): 1003-1005

    View details for DOI 10.1111/his.13307

    View details for PubMedID 28703285

  • Pathology of Neuroendocrine Tumours of the Female Genital Tract CURRENT ONCOLOGY REPORTS Howitt, B. E., Kelly, P., McCluggage, W. 2017; 19 (9): 59


    Neuroendocrine tumours are uncommon or rare at all sites in the female genital tract. The 2014 World Health Organisation (WHO) Classification of neuroendocrine tumours of the endometrium, cervix, vagina and vulva has been updated with adoption of the terms low-grade neuroendocrine tumour and high-grade neuroendocrine carcinoma. In the endometrium and cervix, high-grade neoplasms are much more prevalent than low-grade and are more common in the cervix than the corpus. In the ovary, low-grade tumours are more common than high-grade carcinomas and the term carcinoid tumour is still used in WHO 2014. The term ovarian small-cell carcinoma of pulmonary type is included in WHO 2014 for a tumour which in other organs is termed high small-cell neuroendocrine carcinoma. Neuroendocrine tumours at various sites within the female genital tract often occur in association with other neoplasms and more uncommonly in pure form.

    View details for DOI 10.1007/s11912-017-0617-2

    View details for Web of Science ID 000407450600003

    View details for PubMedID 28735441

  • HPV-negative Gastric Type Adenocarcinoma In Situ of the Cervix: A Spectrum of Rare Lesions Exhibiting Gastric and Intestinal Differentiation AMERICAN JOURNAL OF SURGICAL PATHOLOGY Talia, K. L., Stewart, C. R., Howitt, B. E., Nucci, M. R., McCluggage, W. 2017; 41 (8): 1023-1033


    In recent years, a number of benign and malignant cervical glandular lesions exhibiting gastric differentiation have been described but premalignant gastric-type lesions have not been well characterized. We report a series of 9 cases of a rare form of cervical adenocarcinoma in situ (AIS) distinguished by gastric and sometimes intestinal differentiation and lack of association with human papillomavirus (HPV) infection. The lesions occurred in women aged 25 to 73 years (mean age 51 y). All cases were located at (or just proximal to) the cervical transformation zone and there was extension to the lower uterine segment in 3 cases, 2 of which also involved the endometrium. In all cases, the normal cervical glandular architecture was largely preserved but in 5 cases there was a mild degree of increased intraglandular architectural complexity. The glandular epithelium ranged from almost purely gastric in type (4 cases) to mixed gastric and intestinal (5 cases), with varying proportions of intermixed goblet cells. In contrast to the basophilic cytoplasm of normal endocervical glands, the gastric-type epithelium was typically predominantly composed of cells with eosinophilic or pale pink cytoplasm, but conspicuous foamy or clear cell cytoplasm was present in some cases. Nuclear atypia was present in all cases but was considered low-grade in 8. High-grade features such as marked nuclear pleomorphism and hyperchromasia were evident in only 1 case. Mitotic activity and apoptotic bodies were present but both were noted to be less frequent than in usual type (HPV-related) AIS. Immunohistochemically, there was usually positive staining with CK 7 (7/7 cases) and MUC 6 (7/8 cases) and some cases were positive with CK 20 (3/7), CDX2 (5/9), PAX 8 (5/9) and CEA (2/6). Estrogen receptor and progesterone receptor were usually negative, although Estrogen receptor was positive in 3 of 9 cases. p16 was negative or exhibited mosaic-type staining (nonblock staining) in all cases and there was mutation-type p53 staining in 2 of 9 cases. HPV molecular testing was negative in all 4 cases tested. We believe this unusual subtype of AIS, which we term "gastric-type AIS (gAIS)," represents a precursor to gastric-type adenocarcinoma of the cervix and suggest that gAIS and so-called "atypical lobular endocervical glandular hyperplasia" are related entities within a spectrum of premalignant gastric-type lesions for which we propose the umbrella term gAIS. The malignant potential and optimal management of gAIS are currently unknown but in one of our cases a gastric-type adenocarcinoma developed 6 years after removal of a cervical polyp which contained gAIS. The introduction of HPV vaccination will result in a relative increase in incidence of premalignant and malignant cervical glandular lesions exhibiting gastric differentiation and these will not be detected by HPV-based screening programs.

    View details for DOI 10.1097/PAS.0000000000000855

    View details for Web of Science ID 000405558300003

    View details for PubMedID 28394803

  • Architectural overlap between benign endocervix and pattern-A endocervical adenocarcinoma: Are all pattern-A tumors invasive? Pathology, research and practice Douglas, G., Howitt, B. E., Schoolmeester, J. K., Schwartz, L., Kos, Z., Islam, S., Djordjevic, B., Parra-Herran, C. 2017; 213 (7): 799-803


    Studies on the pattern-based classification for invasive endocervical adenocarcinoma showed that tumors with nondestructive invasion (pattern-A) have a 0% rate of nodal metastases. Our understanding of pattern-A tumors and their distinction from in-situ adenocarcinoma requires further study. Thirteen sections diagnosed independently as pattern-A adenocarcinoma by three gynecologic pathologists, and 14 sections of benign endocervix were selected. Three additional pathologists (reviewers) evaluated a digital image from each section and classified it as pattern-A or benign based on architecture only. To blind the interpretation to cytologic features, nuclei and cytoplasm were obscured using morphometric software (Zen 2011, Carl Zeiss Microscopy, Germany). 13/27 cases (48%; 8 pattern-A, 5 benign) were correctly classified by all reviewers; 19/27 (70%; 10 pattern-A, 9 benign) were correctly classified by ≥2 reviewers. 3/13 pattern-A cases (23%) were interpreted as benign by ≥2 reviewers. Conversely, 5/14 benign cervices (36%) were misinterpreted as pattern-A by ≥2 reviewers. The number of glands per 20× field was higher in pattern-A cases with high reviewer agreement (p=0.004). An abnormal architecture is seen in many pattern-A adenocarcinomas in support of their invasive nature; some, however, have architecture that overlaps with that of benign endocervix thus may actually represent in-situ lesions. Likewise, normal cervix can be architecturally complex and mirror patterns that pathologists would classify as pattern-A if malignant cytologic features were present. Based on this overlap and the nil risk of nodal spread, an emphasis on the non-destructive, rather than the invasive, nature of pattern-A adenocarcinoma is recommended.

    View details for DOI 10.1016/j.prp.2017.03.008

    View details for PubMedID 28554747

  • Comprehensive Human Papillomavirus Genotyping in Cervical Squamous Cell Carcinomas and Its Relevance to Cervical Cancer Prevention in Malawian Women. Journal of global oncology Howitt, B. E., Herfs, M., Tomoka, T., Kamiza, S., Gheit, T., Tommasino, M., Delvenne, P., Crum, C. P., Milner, D. 2017; 3 (3): 227-234


    Cervical squamous cell carcinoma (SCC) continues to be a significant cause of cancer morbidity and is the third leading cause of cancer-related death in women worldwide. In sub-Saharan Africa, cervical cancer is not only the most common female cancer but also the leading cause of cancer-related deaths in women. Malawi, in particular, has the highest burden of cervical cancer. With the increasing use of human papillomavirus (HPV) vaccination, documenting the prevalent HPV types in those high-risk populations is necessary to both manage expectations of HPV vaccination and guide future vaccine development.In this study, we performed HPV typing on 474 cervical SCC samples and analyzed the potential impact of HPV vaccination in this population.Ninety-seven percent of tumors were positive for at least one HPV type, and 54% harbored more than one HPV type. HPV 16 was the most common type (82%), followed by HPV 18 (34%), HPV 35 (24%), and HPV 31 (12%). A vaccine against HPV 16 and 18 would ideally prevent 53% of cervical SCC, and the nonavalent HPV vaccine (covering HPV 16, 18, 31, 33, 45, 52, and 58) would prevent 71% of cervical SCC in Malawi (assuming 100% vaccine efficacy). The main reason for a lack of coverage was high prevalence of HPV 35, which was also present as a single infection in a small subset of patients.Although any HPV vaccination in this population would likely prevent a significant proportion of cervical cancer, the nonavalent vaccine would provide better coverage. Furthermore, investigation of the role of HPV 35 in this population, including possible cross-protection with other HPV types, should be pursued.

    View details for DOI 10.1200/JGO.2015.001909

    View details for PubMedID 28717764

    View details for PubMedCentralID PMC5493214

  • The Flip Side of NIFTP: an Increase in Rates of Unfavorable Histologic Parameters in the Remainder of Papillary Thyroid Carcinomas ENDOCRINE PATHOLOGY Wong, K. S., Strickland, K. C., Angell, T. E., Nehs, M. A., Alexander, E. K., Cibas, E. S., Krane, J. F., Howitt, B. E., Barletta, J. A. 2017; 28 (2): 171-176


    The term noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) was recently proposed to replace noninvasive follicular variant of papillary thyroid carcinoma (FVPTC) both to promote more conservative management of these tumors and spare patients the psychological burden of a cancer diagnosis. This reclassification will lower the incidence of papillary thyroid carcinoma (PTC). In addition, it could result in an increase in the rates of unfavorable histologic prognosticators for PTC overall because NIFTPs had previously accounted for many of the PTCs without these features. Our aim was to evaluate the potential impact of the reclassification of NIFTP on the rates of extrathyroidal extension, lymphovascular invasion, and lymph node metastases in PTC. We identified all PTCs clinically over 1 cm diagnosed on surgical resection between August 2010 and August 2012. The histopathologic characteristics, including PTC subtype, tumor size, presence of extrathyroidal extension and lymphovascular invasion, and surgical margin and lymph node status were all recorded. Based on these parameters, cases were classified according to the American Thyroid Association (ATA) risk stratification system for structural disease recurrence. Tumor slides for cases initially diagnosed as FVPTC were reviewed to identify tumors that would now be classified as NIFTPs. Our cohort included 348 cases of PTC, of which 94 (27%) would now be classified as NIFTPs. After excluding NIFTPs from the PTC category, there were increased rates of extrathyroidal extension (26% up from 19%, p = 0.046), lymphovascular invasion (37% up from 27%, p = 0.0099), and lymph node metastases (26% up from 19%, p = 0.045) among the remaining PTCs. Based on these changes in histologic features, 10% fewer cases were defined as ATA low risk (62% down from 72%, p = 0.0081). Our results indicate that the downgrading of some carcinomas to NIFTP will increase the rates of higher risk histologic parameters in the remaining PTCs by statistically significant margins. Although the overall survival for PTC is very high and would likely not be changed significantly by the introduction of NIFTP, additional studies evaluating the impact of the NIFTP shift are warranted.

    View details for DOI 10.1007/s12022-017-9476-5

    View details for Web of Science ID 000401077400011

    View details for PubMedID 28271380

  • Frequency of "incidental" serous tubal intraepithelial carcinoma (STIC) in women without a history of or genetic risk factor for high-grade serous carcinoma: A six-year study. Gynecologic oncology Meserve, E. E., Mirkovic, J., Conner, J. R., Yang, E., Muto, M. G., Horowitz, N., Strickland, K. C., Howitt, B. E., Crum, C. P. 2017


    Objective The purpose of this study was to determine the prevalence of incidentally discovered serous tubal intraepithelial carcinoma in women without a genetic risk for or history of high grade serous carcinoma (HGSC) in the gynecologic tract.All pathology reports at our institution that included bilateral salpingectomies from January 2006-December 2011 were examined in women >50years old in which the entire tube or the distal one-third was examined histologically with the complete (proximal and distal fallopian tube) or modified (distal one third of the tube) SEE-FIM protocol. Cases were divided into: Group 1, a history of or known risk factors (BRCA1 or BRCA2 mutations) for HGSC and Group 2, those without these attributes for whom a STIC would be unexpected (incidental). Women undergoing unspecified "risk-reducing" procedures were included in Group 1.Of 4051 identified total, 2268 had complete examination of the distal fallopian tube and were age 50 or above. Of these, 1747 were in group 2. Two STICs were identified (0.1%), one associated with a grade 2 endometrial endometrioid adenocarcinoma and one with a low-grade ovarian serous carcinoma in the setting of a serous borderline tumor.Incidental STICs in women over age 50 are uncommon. However, the significance of lesser tubal atypias (0.3% in this study), risk of STIC in women with no epithelial pathology and the risk imposed by coexisting endometrioid neoplasia are unclear and require further study.

    View details for DOI 10.1016/j.ygyno.2017.04.015

    View details for PubMedID 28479065

  • Sentinel lymph node mapping reduces practice pattern variations in surgical staging for endometrial adenocarcinoma: A before and after study GYNECOLOGIC ONCOLOGY Liu, C. Y., Elias, K. M., Howitt, B. E., Lee, L. J., Feltmate, C. M. 2017; 145 (2): 248-255


    To examine the effects of universal sentinel lymph node mapping on the use of nodal staging in endometrial adenocarcinoma.Two approaches to laparoscopic staging for endometrial adenocarcinoma were compared using a before and after study design. The before cohort underwent selective lymphadenectomy from January 1, 2014-October 1, 2015 while the after cohort underwent universal sentinel lymph node (SLN) mapping from October 2, 2015-September 29, 2016.The before cohort comprised 215 patients and the after cohort 166 patients. In women undergoing SLN mapping, a sentinel node was identified at least unilaterally in 146/153 cases (95.4%), and bilaterally in 114/153 (74.5%) of cases. Pelvic nodes were removed in 35.8% of the before cohort versus 92.2% of the after cohort (p<0.0001) with more nodal evaluation among both low risk (9.6% vs. 91%, p<0.0001) and high risk cases (66% vs. 94%, p<0.0001). While the proportion of low risk cases diagnosed with nodal involvement did not significantly change (0.9% to 3.1%, p=0.32), there was a trend toward more diagnoses of nodal involvement in high risk cases (5% to 13.2%, p=0.06). Mean number of pelvic lymph nodes removed (15 vs. 4, p<0.0001), mean operative time (181min vs. 137min, p<0.0001), estimated blood loss (80ml vs. 56ml, p=0.004), and rate of post-operative complications (13% vs. 5.2%, p=0.04) all decreased after the adoption of SLN dissection.Universal sentinel lymph node dissection for laparoscopic endometrial cancer staging reduces heterogeneity in surgeon staging practice, increases nodal detection, and lowers post-operative complications.

    View details for DOI 10.1016/j.ygyno.2017.03.012

    View details for Web of Science ID 000400954400007

    View details for PubMedID 28363672

  • Universal Screening for Mismatch-Repair Deficiency in Endometrial Cancers to Identify Patients With Lynch Syndrome and Lynch-like Syndrome. International journal of gynecological pathology Watkins, J. C., Yang, E. J., Muto, M. G., Feltmate, C. M., Berkowitz, R. S., Horowitz, N. S., Syngal, S., Yurgelun, M. B., Chittenden, A., Hornick, J. L., Crum, C. P., Sholl, L. M., Howitt, B. E. 2017; 36 (2): 115-127


    Although consensus has yet to be reached on universal mismatch-repair (MMR) protein immunohistochemical (IHC) screening for Lynch syndrome (LS) in endometrial cancer (EC), an increasing number of institutions have adopted universal screening protocols similar to those used for colorectal carcinoma. Here we describe our institution's experience with a prospective universal screening protocol in which all ECs resected over a period of 19 months (n=242) were screened for MLH1, PMS2, MSH2, and MSH6 deficiencies using IHC, followed by MLH1 promoter methylation testing when appropriate. When consent was obtained, tumor samples underwent next-generation sequencing. A total of 11 unmethylated MMR-deficient cases (4.5% of cohort) were identified through IHC screening. Germline testing was performed in 10 cases and confirmed LS in 4 patients (1.7% of cohort). Of our 4 confirmed LS cases, 1 did not meet traditional LS screening criteria (eg, age below 50 y, Revised Bethesda criteria). In addition, universal screening identified 6 germline-negative MMR-deficient nonmethylated cases, 4 of which occurred in women older than 50. Although our next-generation sequencing data suggest somatic mutations in 4 of these cases, it is possible that these cases may represent cases of "Lynch-like syndrome." We conclude that a subset of LS cases could be missed using traditional screening guidelines. The value of screening for Lynch-like syndrome has yet to be determined. Although the cost-effectiveness of universal screening in EC has yet to be elucidated, we conclude that universal IHC screening is currently a reasonable, and arguably superior, approach to screening for LS.

    View details for DOI 10.1097/PGP.0000000000000312

    View details for PubMedID 27556954

  • Differentiated exophytic vulvar intraepithelial lesions are genetically distinct from keratinizing squamous cell carcinomas and contain mutations in PIK3CA. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc Watkins, J. C., Howitt, B. E., Horowitz, N. S., Ritterhouse, L. L., Dong, F., MacConaill, L. E., Garcia, E., Lindeman, N. I., Lee, L. J., Berkowitz, R. S., Nucci, M. R., Crum, C. P. 2017; 30 (3): 448-458


    Human papillomavirus-negative keratinizing vulvar cancers typically harbor TP53 mutations as do their precursors, differentiated vulvar intraepithelial neoplasia. However, atypical verruciform proliferations are also associated with these malignancies and their pathogenesis is poorly understood. This study compared 11 atypical verruciform lesions, including atypical verruciform hyperplasia, vulvar acanthosis with altered differentiation, and verruciform lichen simplex chronicus, with 14 human papillomavirus-negative keratinizing squamous cell carcinomas. Extracted tissue DNA was subjected to targeted massively parallel sequencing of the exonic regions of 300 genes. Eight (73%) and six (55%) of eleven atypical verruciform lesions contained mutations in PIK3CA and ARID2, respectively. No TP53 mutations were identified. Eleven (79%) and five (36%) of fourteen keratinizing squamous cell carcinomas tested contained TP53 and CDKN2A mutations, respectively. Keratinizing squamous cell carcinomas displayed the majority of copy number variations with some variations (7p gain and 8p loss) shared by some cases in both groups. One patient developed atypical verruciform lesions with PIK3CA mutations followed by a keratinizing carcinoma with mutations in both PIK3CA and TP53. This study, for the first time segregates atypical verruciform lesions by virtue of a unique genotype (PIK3CA mutant/TP53 wild type) illustrating an example of progression to a TP53-mutated keratinizing carcinoma. The findings indicate that although PIK3CA mutations are found in <10% of vulvar squamous cell carcinomas, they may be specific for a particular pathway involving atypical verruciform lesions, which could function as either a direct precursor or a risk factor for vulvar squamous cell carcinoma. Given the presence of a molecular signature, we propose the term 'differentiated exophytic vulvar intraepithelial lesion' for this group. Whether they function as direct precursors to a less common form of squamous cell carcinoma will require further study, but carcinomas associated with these lesions might warrant testing for PIK3CA mutations to address this question.

    View details for DOI 10.1038/modpathol.2016.187

    View details for PubMedID 27834349

  • Predicted neoantigen load in non-hypermutated endometrial cancers: Correlation with outcome and tumor-specific genomic alterations. Gynecologic oncology reports Shukla, S. A., Howitt, B. E., Wu, C. J., Konstantinopoulos, P. A. 2017; 19: 42-45


    Elevated neoantigen load has been previously correlated with improved outcome and response to immune checkpoint blockade in various tumor types. In endometrial cancer, previous studies of neoantigen load prediction have shown that the hypermutated MSI and POLE-mutated tumors harbor significantly higher predicted neoantigen load compared to the hypomutated CN-low/endometrioid and CN-high/serous-like tumors. Here, we report that predicted neoantigen load may be a prognostic factor in hypomutated endometrial cancers, both in CN-low/endometrioid and CN-high/serous-like tumors. Specifically, in the TCGA dataset, CN-low/endometrioid tumors with neoantigen load in the highest tertile were associated with significantly improved progression free survival (PFS) (p = 0.031), while CN-high/serous-like tumors with neoantigen load in the lowest tertile were associated with worse PFS (p = 0.041). Importantly, certain tumor-specific genomic alterations were enriched in tumors with lower neoantigen load, including CTNNB1 mutations in CN-low/endometrioid tumors and MYC amplification and PIK3CA mutations in CN-high/serous-like tumors. These findings suggest that predicted neoantigen load and specific genomic alterations (such as CTNNB1 mutations, MYC amplification and PIK3CA mutations) may be biomarkers of response to immunotherapy in hypomutated endometrial cancers, and argues that these exploratory biomarkers should be incorporated in clinical trials of immune checkpoint blockade in this disease.

    View details for DOI 10.1016/j.gore.2016.12.009

    View details for PubMedID 28070553

    View details for PubMedCentralID PMC5219603

  • Clear cell ovarian cancers with microsatellite instability: A unique subset of ovarian cancers with increased tumor-infiltrating lymphocytes and PD-1/PD-L1 expression. Oncoimmunology Howitt, B. E., Strickland, K. C., Sholl, L. M., Rodig, S., Ritterhouse, L. L., Chowdhury, D., D'Andrea, A. D., Matulonis, U. A., Konstantinopoulos, P. A. 2017; 6 (2): e1277308


    Clear cell ovarian carcinoma (CCOC) represents a distinct histologic subtype of ovarian cancer associated with significantly worse prognosis across all stages and no effective therapeutic options. Here, we report a rare but clinically important cohort of CCOCs with microsatellite instability (MSI) (MSI-CCOCs), which are highly immunogenic and may thus be very responsive to immune checkpoint blockade. CCOCs with MSI exhibit a significantly higher number of CD8+ TILs, higher CD8+/CD4+ ratio, and higher PD-1+ TILs compared with microsatellite stable (MSS) CCOCs and compared with high grade serous ovarian cancers, which are the most common histologic subtype of ovarian cancer. Of note, PD-L1 expression in tumor cells or immune cells was noted in all cases of CCOCs with MSI. These observations open an alternative therapeutic avenue for a fraction of patients with CCOC and argue for the routine testing of CCOCs for MSI, a test that is not currently routinely performed.

    View details for DOI 10.1080/2162402X.2016.1277308

    View details for PubMedID 28344892

    View details for PubMedCentralID PMC5353914

  • Involvement of Chromosome 8 in Müllerian Adenosarcoma. International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Howitt, B. E., Dal Cin, P., Nucci, M. R., Quade, B. J. 2017; 36 (1): 24-30


    Müllerian adenosarcoma (MA) is an uncommon biphasic neoplasm of the female genital tract, composed of malignant stroma and benign epithelium. Little is known about the molecular and cytogenetic aberrations in MA pathogenesis, including those with progression to sarcomatous overgrowth (SO). Herein, we report all cases of MA in which karyotyping was attempted at our institution. Twenty-one samples from 20 subjects consisted of 15 primary (7 without SO, 8 with SO) and 6 metastatic MA, were cytogenetically investigated in our institution. Karyotypes were successfully obtained in 14/21 (67%) cases and 9 (45%) had cytogenetic aberrations. Two (1 MA with SO and 1 metastatic MA) were markedly complex, displaying extreme aneuploidy with numerous rearrangements. Seven (2 MA without SO, 3 MA with SO, and 2 metastatic MA) demonstrated noncomplex clonal aberrations, of which 5 (71%) included an abnormality involving chromosome 8. Two tumors had rearrangements at 8q13 and another 3 tumors had extra copies of chromosome 8. In 5 cases, a normal karyotype (46,XX) was obtained (2 MA without SO, 2 MA with SO, and 1 metastatic MA). Further study is warranted to explore the genetic mechanism by which chromosome abnormalities, particularly those at 8q13, contribute to MA tumorigenesis.

    View details for DOI 10.1097/PGP.0000000000000287

    View details for PubMedID 26974998

  • A BRCA1/2 Mutational Signature and Survival in Ovarian High-Grade Serous Carcinoma. Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology Dong, F., Davineni, P. K., Howitt, B. E., Beck, A. H. 2016; 25 (11): 1511-1516


    Mutational signatures have been identified by the broad sequencing of cancer genomes and reflect underlying processes of mutagenesis. The clinical application of mutational signatures is not well defined. Here we aim to assess the prognostic utility of mutational signatures in ovarian high-grade serous carcinoma.Open access data of 15,439 somatic mutations of 310 ovarian high-grade serous carcinomas from The Cancer Genome Atlas (TCGA) are used to construct a Bayesian model to classify each cancer as either having or lacking a BRCA1/2 mutational signature. We evaluate the association of the BRCA1/2 signature with overall survival on the TCGA dataset and on an independent cohort of 92 ovarian high-grade serous carcinomas from the Australian Ovarian Cancer Study (AOCS).Patients from TCGA with tumors harboring the BRCA1/2 mutational signature have improved survival (55.2 months vs. 38.0 months), which is independent of BRCA1/2 gene mutation status, age, stage, and grade (HR = 0.64; P = 0.02). In the AOCS dataset, the BRCA1/2 mutational signature is also associated with improved overall survival (46.3 months vs. 23.6 months) independent of age and stage (HR = 0.52; P = 0.007).A BRCA1/2 mutational signature is a prognostic marker in ovarian high-grade serous carcinoma. Mutational signature analysis of ovarian cancer genomes may be useful in addition to testing for BRCA1/2 mutations.This study identifies the use of mutational signatures as a biomarker for survival outcome in ovarian high-grade serous carcinoma. Cancer Epidemiol Biomarkers Prev; 25(11); 1511-6. ©2016 AACR.

    View details for DOI 10.1158/1055-9965.EPI-16-0286

    View details for PubMedID 27496093

  • XXIX. Dr Hazel Mansell Gore INTERNATIONAL JOURNAL OF GYNECOLOGICAL PATHOLOGY Howitt, B. E., Nucci, M. R., Young, R. H. 2016; 35 (6): 598-605

    View details for DOI 10.1097/PGP.0000000000000327

    View details for Web of Science ID 000386415500015

    View details for PubMedID 27662037

  • SUSD2 expression in high-grade serous ovarian cancer correlates with increased patient survival and defective mesothelial clearance ONCOGENESIS Sheets, J. N., Iwanicki, M., Liu, J. F., Howitt, B. E., Hirsch, M. S., Gubbels, J. A., Drapkin, R., Egland, K. A. 2016; 5: e264


    The cause of death among the majority of epithelial ovarian cancer (EOC) patients involves passive dissemination of cancer cells within the peritoneal cavity and subsequent implantation of cancer spheroids into adjacent organs. Thus, it is important to identify the factors that mediate EOC metastasis and implantation, including clearance of the mesothelium. Sushi domain containing 2 (SUSD2) encodes a type I transmembrane protein containing several functional domains inherent to adhesion molecules. Immunohistochemical analysis determined the presence of SUSD2 in several subtypes of EOC, with the strongest staining observed in high-grade serous ovarian carcinomas (HGSOCs). A high-density, clinically annotated HGSOC tissue microarray was stained with an anti-SUSD2 antibody. Patients with tumors that had a low percentage of SUSD2 staining cells had a shorter median survival (31.7 months) compared with patients who had tumors with extensive SUSD2 staining (49.1 months; P-value=0.0083). To investigate the role of SUSD2 in HGSOCs, stable OVCAR3, OVSAHO and KURAMOCHI cell lines were established with knockdown (KD) or non-targeting (NT) of SUSD2. Boyden chamber and wound-healing assays demonstrated that OVCAR3, OVSAHO and KURAMOCHI SUSD2-KD cells migrated at significantly higher rates compared with their SUSD2 NT counterpart cell lines. Quantitative reverse transcription-PCR and western immunoblot analysis indicated an inverse relationship between SUSD2 and well-characterized mesenchymal proteins, including Twist-1, Zeb-1, N-cadherin, STEAP1, AHNAK, Snail-1, COL5A2 and Snail-3 in OVCAR3, OVSAHO and KURAMOCHI cell line models. In addition, OVCAR3 and KURAMOCHI SUSD2-KD spheroids displayed increased mesothelial clearance ability compared with cells that express endogenous levels of SUSD2. These data suggest that SUSD2 has a role in the inhibition of mesothelial clearance, which is required for metastasis. Altogether, our findings indicate that SUSD2 impedes migration, epithelial-to-mesenchymal transitional and mesothelial clearance of HGSOC cells, consistent with prolonged survival of patients with SUSD2-expressing tumors.

    View details for DOI 10.1038/oncsis.2016.64

    View details for Web of Science ID 000391947700005

    View details for PubMedID 27775699

    View details for PubMedCentralID PMC5117850

  • Molecular Pathology: Predictive, Prognostic, and Diagnostic Markers in Uterine Tumors. Surgical pathology clinics Ritterhouse, L. L., Howitt, B. E. 2016; 9 (3): 405-26


    This article focuses on the diagnostic, prognostic, and predictive molecular biomarkers in uterine malignancies, in the context of morphologic diagnoses. The histologic classification of endometrial carcinomas is reviewed first, followed by the description and molecular classification of endometrial epithelial malignancies in the context of histologic classification. Taken together, the molecular and histologic classifications help clinicians to approach troublesome areas encountered in clinical practice and evaluate the utility of molecular alterations in the diagnosis and subclassification of endometrial carcinomas. Putative prognostic markers are reviewed. The use of molecular alterations and surrogate immunohistochemistry as prognostic and predictive markers is also discussed.

    View details for DOI 10.1016/j.path.2016.04.006

    View details for PubMedID 27523969

  • Ovarian cancer NATURE REVIEWS DISEASE PRIMERS Matulonis, U. A., Sood, A. K., Fallowfield, L., Howitt, B. E., Sehouli, J., Karlan, B. Y. 2016; 2: 16061


    Ovarian cancer is not a single disease and can be subdivided into at least five different histological subtypes that have different identifiable risk factors, cells of origin, molecular compositions, clinical features and treatments. Ovarian cancer is a global problem, is typically diagnosed at a late stage and has no effective screening strategy. Standard treatments for newly diagnosed cancer consist of cytoreductive surgery and platinum-based chemotherapy. In recurrent cancer, chemotherapy, anti-angiogenic agents and poly(ADP-ribose) polymerase inhibitors are used, and immunological therapies are currently being tested. High-grade serous carcinoma (HGSC) is the most commonly diagnosed form of ovarian cancer and at diagnosis is typically very responsive to platinum-based chemotherapy. However, in addition to the other histologies, HGSCs frequently relapse and become increasingly resistant to chemotherapy. Consequently, understanding the mechanisms underlying platinum resistance and finding ways to overcome them are active areas of study in ovarian cancer. Substantial progress has been made in identifying genes that are associated with a high risk of ovarian cancer (such as BRCA1 and BRCA2), as well as a precursor lesion of HGSC called serous tubal intraepithelial carcinoma, which holds promise for identifying individuals at high risk of developing the disease and for developing prevention strategies.

    View details for DOI 10.1038/nrdp.2016.61

    View details for Web of Science ID 000384876800001

    View details for PubMedID 27558151

  • Pattern-based classification of invasive endocervical adenocarcinoma, depth of invasion measurement and distinction from adenocarcinoma in situ: interobserver variation among gynecologic pathologists. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc Parra-Herran, C., Taljaard, M., Djordjevic, B., Reyes, M. C., Schwartz, L., Schoolmeester, J. K., Lastra, R. R., Quick, C. M., Laury, A., Rasty, G., Nucci, M. R., Howitt, B. E. 2016; 29 (8): 879-92


    A pattern-based classification for invasive endocervical adenocarcinoma has been proposed as predictive of the risk of nodal metastases. We aimed to determine the reproducibility of such classification in the context of common diagnostic challenges: distinction between in situ and invasive adenocarcinoma and depth of invasion measurement. Nine gynecologic pathologists independently reviewed 96 cases of endocervical adenocarcinoma (two slides per case). They diagnosed each case as in situ or invasive carcinoma classifying the latter following the pattern-based classification as pattern A (non-destructive), B (focally destructive) or C (diffusely destructive). Depth of invasion, when applicable, was measured (mm). Overall, diagnostic reproducibility of pattern diagnosis was good (κ=0.65). Perfect agreement (9/9 reviewers) was seen in only 11 cases (11%), all destructively invasive (10 pattern C and 1 pattern B). In all, ≥5/9 reviewer concordance was achieved in 82/96 cases (85%). Distinction between in situ and invasive carcinoma, regardless of the pattern, showed only slight agreement (κ=0.37). Likewise, distinction restricted to in situ versus pattern A was poor (κ=0.23). Distinction between non-destructive (in situ+pattern A) and destructive (patterns B+C) carcinoma showed significantly higher agreement (κ=0.62). Estimation of depth of invasion showed excellent reproducibility (ICC=0.82). However, different measurements resulting in differing FIGO stages were common (from at least 1 reviewer in 79% cases). On the basis of interobserver agreement, the pattern-based classification is best at diagnosing destructive invasion, which carries a risk for nodal metastases. Agreement in diagnosing in situ versus invasive carcinoma, including pattern A, was poor. Given the nil risk of nodal spread in in situ and pattern A lesions, the term 'endocervical adenocarcinoma with non-destructive growth' can be considered when the distinction is difficult, after excluding destructive invasion. Depth of invasion measurement was highly reproducible among pathologists; thus, the pattern-based approach can complement, but should not replace, the depth of invasion metric.

    View details for DOI 10.1038/modpathol.2016.86

    View details for PubMedID 27174588

  • Morphologic correlates of molecular alterations in extrauterine Müllerian carcinomas. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc Ritterhouse, L. L., Nowak, J. A., Strickland, K. C., Garcia, E. P., Jia, Y., Lindeman, N. I., Macconaill, L. E., Konstantinopoulos, P. A., Matulonis, U. A., Liu, J., Berkowitz, R. S., Nucci, M. R., Crum, C. P., Sholl, L. M., Howitt, B. E. 2016; 29 (8): 893-903


    Extrauterine high-grade serous carcinomas can exhibit various histologic patterns including (1) classic architecture that is papillary, micropapillary and infiltrative and (2) solid, endometrioid, and transitional (ie, SET) patterns. Although the SET pattern has been associated with germline BRCA mutations, potential molecular underpinnings have not been fully investigated. DNA was isolated from 174 carcinomas of the fallopian tube, ovary, or peritoneum. Targeted next-generation sequencing was performed and single-nucleotide and copy number variants were correlated with morphologic subtype. Overall, 79% of tumors were classified as high-grade serous carcinoma (n=138), and the most common mutations in high-grade serous carcinomas were TP53 (94%), BRCA1 (25%), BRCA2 (11%), and ATM (7%). Among chemotherapy-naive high-grade serous carcinomas, 40 cases exhibited classic morphology and 40 cases had non-classic morphology (SET or ambiguous features). Mutations in homologous recombination pathways were seen across all tumor histotypes. High-grade serous carcinomas with homologous recombination mutations were six times more likely to be associated with non-classic histology (P=0.002) and were significantly more likely to be platinum sensitive and have improved progression-free survival (PFS) (P=0.007 and P=0.004, respectively). In a multivariate analysis adjusted for age, homologous recombination mutation status and increased copy number variants were independently associated with improved PFS (P=0.008 and P=0.005, respectively). These findings underscore the potential significance of variant morphologic patterns and comprehensive genomic analysis in high-grade serous carcinomas with potential implications for pathogenesis, as well as response to targeted therapies.

    View details for DOI 10.1038/modpathol.2016.82

    View details for PubMedID 27150160

  • Unusual Mismatch Repair Immunohistochemical Patterns in Endometrial Carcinoma. The American journal of surgical pathology Watkins, J. C., Nucci, M. R., Ritterhouse, L. L., Howitt, B. E., Sholl, L. M. 2016; 40 (7): 909-16


    Universal screening for Lynch syndrome through mismatch repair (MMR) immunohistochemistry (IHC) on tumor samples has brought to light several heterogenous MMR staining patterns. At our institution, a prospective study of universal Lynch syndrome screening using MMR IHC on 125 endometrial cancers (EC) led to the identification of subclonal loss of MMR protein expression within the tumor (n=9). We also interrogated the MMR staining patterns in MMR-deficient EC with concurrent endometrial intraepithelial neoplasia (EIN; n=14) and all mixed-type ECs (n=14) to look for concordant or discordant profiles between the various components. MLH1 promoter methylation and microsatellite instability testing was performed on discordant subclones. Abrupt and complete subclonal loss of MMR expression was identified in 9 cases (7.2%; 7 subclonal MLH1/PMS2 loss, 1 subclonal loss of MLH1 and complete loss of PMS2, and 1 subclonal MSH6 loss). All subclonal MLH1 losses were associated with epigenetic silencing. In cases with concomitant EIN (n=14), 7 cases showed concordant MMR IHC between EC and EIN, and 4 cases showed MMR protein loss confined to the EC. The remaining 3 cases demonstrated subclonal staining in the EIN. In mixed tumors (n=14), subclonal or total MMR IHC deficiency was confined to endometrioid components. In summary, discrete subclonal loss of MMR protein expression occurs in up to 7.2% of EC and, in our experience, only in endometrioid components. Importantly, subclonal MLH1 MMR defects appear to be a biological phenomenon that can be explained by methylation and somatic events, without evidence of underlying germline alterations.

    View details for DOI 10.1097/PAS.0000000000000663

    View details for PubMedID 27186853

  • Somatic mutations and copy number variations in cancer-associated genes in 695 ovarian cancer patients Stover, E. H., Howitt, B., Lindeman, N. I., Garraway, L. A., Matulonis, U. A. AMER ASSOC CANCER RESEARCH. 2016
  • Genetic Basis for PD-L1 Expression in Squamous Cell Carcinomas of the Cervix and Vulva. JAMA oncology Howitt, B. E., Sun, H. H., Roemer, M. G., Kelley, A., Chapuy, B., Aviki, E., Pak, C., Connelly, C., Gjini, E., Shi, Y., Lee, L., Viswanathan, A., Horowitz, N., Neuberg, D., Crum, C. P., Lindeman, N. L., Kuo, F., Ligon, A. H., Freeman, G. J., Hodi, F. S., Shipp, M. A., Rodig, S. J. 2016; 2 (4): 518-22


    Patients with squamous cell carcinoma (SCC) of the cervix or vulva have limited therapeutic options, and the potential for immunotherapy for this population has not been evaluated. Recent trials suggest that tumors with a genetic basis for PD-1 (programmed cell death protein 1) ligand expression are highly sensitive to therapeutic antibodies targeting PD-1.To determine the genetic status of CD274 (encoding PD-L1 [programmed cell death 1 ligand 1]) and PDCD1LG2 (encoding PD-L2 [programmed cell death 1 ligand 2]) in SCCs of the cervix and vulva and to correlate the findings with PD-L1 protein expression.We performed fluorescence in situ hybridization (FISH) using probes targeting CD274, PDCD1LG2, and the centromeric portion of chromosome 9, and immunohistochemistry (IHC) using an antibody recognizing PD-L1 on formalin-fixed, paraffin-embedded (FFPE) biopsy specimens from 48 cervical SCCs and 23 vulvar SCCs.Tumors were categorized according to the genetic abnormality in CD274 and PDCD1LG2 (coamplification > cogain > polysomy > disomy) as detected by FISH, and evaluated on a semiquantitative scale (modified H score, the product of the percentage of tumor cells with positive staining and the maximum intensity of positive staining) for PD-L1 protein expression as detected by IHC.Overall, 71 samples of FFPE tissue from cases of cervical SCCs (n = 48) and vulvar SCCs (n = 23) were retrieved from the archives of Brigham and Women's Hospital and included in this study. We observed cogain or coamplification of CD274 and PDCD1LG2 in 32 of 48 cervical SCCs (67%) and 10 of 23 vulvar SCCs (43%). Median PD-L1 protein expression was highest among tumors with CD274 and PDCD1LG2 coamplification and lowest among tumors with disomy.Recurrent copy number gain of the genes encoding the PD-1 ligands provides a genetic basis for PD-L1 expression in a subset of cervical and vulvar SCCs and identifies a class of patients that are rational candidates for therapies targeting PD-1.

    View details for DOI 10.1001/jamaoncol.2015.6326

    View details for PubMedID 26913631

  • Association and prognostic significance of BRCA1/2-mutation status with neoantigen load, number of tumor-infiltrating lymphocytes and expression of PD-1/PD-L1 in high grade serous ovarian cancer. Oncotarget Strickland, K. C., Howitt, B. E., Shukla, S. A., Rodig, S., Ritterhouse, L. L., Liu, J. F., Garber, J. E., Chowdhury, D., Wu, C. J., D'Andrea, A. D., Matulonis, U. A., Konstantinopoulos, P. A. 2016; 7 (12): 13587-98


    Immune checkpoint inhibitors (e.g., anti-PD-1 and anti-PD-L1 antibodies) have demonstrated remarkable efficacy against hypermutated cancers such as melanomas and lung carcinomas. One explanation for this effect is that hypermutated lesions harbor more tumor-specific neoantigens that stimulate recruitment of an increased number of tumor-infiltrating lymphocytes (TILs), which is counterbalanced by overexpression of immune checkpoints such as PD-1 or PD-L1. Given that BRCA1/2-mutated high grade serous ovarian cancers (HGSOCs) exhibit a higher mutational load and a unique mutational signature with an elevated number of larger indels up to 50 bp, we hypothesized that they may also harbor more tumor-specific neoantigens, and, therefore, exhibit increased TILs and PD-1/PD-L1 expression. Here, we report significantly higher predicted neoantigens in BRCA1/2-mutated tumors compared to tumors without alterations in homologous recombination (HR) genes (HR-proficient tumors). Tumors with higher neoantigen load were associated with improved overall survival and higher expression of immune genes associated with tumor cytotoxicity such as genes of the TCR, the IFN-gamma and the TNFR pathways. Furthermore, immunohistochemistry studies demonstrated that BRCA1/2-mutated tumors exhibited significantly increased CD3+ and CD8+ TILs, as well as elevated expression of PD-1 and PD-L1 in tumor-associated immune cells compared to HR-proficient tumors. Survival analysis showed that both BRCA1/2-mutation status and number of TILs were independently associated with outcome. Of note, two distinct groups of HGSOCs, one with very poor prognosis (HR proficient with low number of TILs) and one with very good prognosis (BRCA1/2-mutated tumors with high number of TILs) were defined. These findings support a link between BRCA1/2-mutation status, immunogenicity and survival, and suggesting that BRCA1/2-mutated HGSOCs may be more sensitive to PD-1/PD-L1 inhibitors compared to HR-proficient HGSOCs.

    View details for DOI 10.18632/oncotarget.7277

    View details for PubMedID 26871470

    View details for PubMedCentralID PMC4924663

  • Mammary-type Myofibroblastoma: Clinicopathologic Characterization in a Series of 143 Cases. The American journal of surgical pathology Howitt, B. E., Fletcher, C. D. 2016; 40 (3): 361-7


    Mammary-type myofibroblastoma (MTMF) is a benign mesenchymal neoplasm initially described to occur in the breast. MTMF is typically CD34 and desmin positive and genetically has rearrangement or deletion of 13q14, resulting in loss of Rb expression by immunohistochemistry (IHC). Although the wider anatomic distribution of MTMF is increasingly recognized, no large series with clinicopathologic information has been reported to date. Archival cases were retrieved, and the diagnosis of MTMF was confirmed. Hematoxylin and eosin-stained slides and IHC slides were reviewed when available (CD34, Desmin, Rb, SMA, S100, EMA, MDM2, CDK4). The patient age, sex, tumor anatomic location and size, preceding symptoms, and margin status were recorded when possible. Clinical follow-up data were requested for tumor recurrence, metastasis, and patient status at last follow-up. A total of 143 cases of MTMF comprised this study, affecting 94 (66%) male and 49 (34%) female individuals. Mean tumor size was 6.6 cm (range, 1 to 22 cm). Anatomic locations included: inguinal/groin region (65; 45%), breast (15; 10%), chest wall/axilla (7; 5%), trunk (17; 12%), lower (18; 13%) and upper (2; 1%) extremities, or intra-abdominal/retroperitoneal (14; 10%). MTMFs were characterized by spindle cells with relatively short, stubby nuclei and a variable adipocytic component. Hyalinization and myxoid stroma were common. Less common morphologic features included nuclear atypia, epithelioid tumor cell morphology, and neurilemmoma-type nuclear palisading. CD34 and desmin were positive in 89% and 91%, respectively, and were both negative in 3%. Rb expression was lost in 92% (57/62). No cases with follow-up data available had tumor recurrence, although 1 case was reportedly a recurrence itself. In summary, MTMF appears more common at extramammary sites than in the breast and can cause diagnostic difficulty when atypia or epithelioid morphology is present or when located in an unusual anatomic location. MTMF is frequently positive for CD34 and desmin by IHC; however, rare cases are negative for both. There is no evidence of any significant recurrence risk for MTMF, even in the presence of positive resection margins. The degree of morphologic overlap between spindle cell lipoma, cellular angiofibroma, and MTMF, in combination with shared genetics and slightly overlapping anatomic distribution, raises the question of whether or not these tumors are truly distinct entities or instead represent points along a single spectrum of genetically related tumors.

    View details for DOI 10.1097/PAS.0000000000000540

    View details for PubMedID 26523539

  • In vitro and in vivo correlates of physiological and neoplastic human Fallopian tube stem cells JOURNAL OF PATHOLOGY Yamamoto, Y., Ning, G., Howitt, B. E., Mehra, K., Wu, L., Wang, X., Hong, Y., Kern, F., Wei, T., Zhang, T., Nagarajan, N., Basuli, D., Torti, S., Brewer, M., Choolani, M., McKeon, F., Crum, C. P., Xian, W. 2016; 238 (4): 519-530


    High-grade serous cancer (HGSC) progresses to advanced stages without symptoms and the 5-year survival rate is a dismal 30%. Recent studies of ovaries and Fallopian tubes in patients with BRCA1 or BRCA2 mutations have documented a pre-metastatic intramucosal neoplasm that is found almost exclusively in the Fallopian tube, termed 'serous tubal intraepithelial carcinoma' or STIC. Moreover, other proliferations, termed p53 signatures, secretory cell outgrowths (SCOUTs), and lower-grade serous tubal intraepithelial neoplasms (STINs) fall short of STIC but share similar alterations in expression, in keeping with an underpinning of genomic disturbances involved in, or occurring in parallel with, serous carcinogenesis. To gain insight into the cellular origins of this unique tubal pathway to high-grade serous cancer, we cloned and both immortalized and transformed Fallopian tube stem cells (FTSCs). We demonstrated that pedigrees of FTSCs were capable of multipotent differentiation and that the tumours derived from transformed FTSCs shared the histological and molecular features of HGSC. We also demonstrated that altered expression of some biomarkers seen in transformed FTSCs and HGSCs (stathmin, EZH2, CXCR4, CXCL12, and FOXM1) could be seen as well in immortalized cells and their in vivo counterparts SCOUTs and STINs. Thus, a whole-genome transcriptome analysis comparing FTSCs, immortalized FTSCs, and transformed FTSCs showed a clear molecular progression sequence that is recapitulated by the spectrum of accumulated perturbations characterizing the range of proliferations seen in vivo. Biomarkers unique to STIC relative to normal tubal epithelium provide a basis for novel detection approaches to early HGSC, but must be viewed critically given their potential expression in lesser proliferations. Perturbations shared by both immortalized and transformed FTSCs may provide unique early targets for prevention strategies. Central to these efforts has been the ability to clone and perpetuate multipotent FTSCs.

    View details for DOI 10.1002/path.4649

    View details for Web of Science ID 000370840000006

    View details for PubMedID 26415052

    View details for PubMedCentralID PMC4895925

  • Uterine Adenosarcoma ARCHIVES OF PATHOLOGY & LABORATORY MEDICINE Pinto, A., Howitt, B. 2016; 140 (3): 286-290


    Müllerian adenosarcoma is an uncommon biphasic tumor composed of malignant stromal and benign epithelial components. Morphologically, adenosarcoma is characterized by a broad leaflike architecture, reminiscent of phyllodes tumors of the breast. Periglandular cuffing of the stromal cells around the compressed or cystically dilated glands is characteristic. The mesenchymal component is typically a low-grade spindle cell sarcoma, whereas the epithelial counterpart is commonly endometrioid with frequent squamous or mucinous metaplasia and may, in some circumstances, show mild to moderate atypia. In all cases, it is important to assess for the presence of sarcomatous overgrowth and myometrial invasion, which are the prognostic factors. In this brief review, we present the clinical, histopathologic, and immunohistochemical features of adenosarcoma, as well as updates on the molecular biology of this neoplasm.

    View details for DOI 10.5858/arpa.2014-0523-RS

    View details for Web of Science ID 000371227800015

    View details for PubMedID 26927725

  • Solitary Fibrous Tumor of the Uterus Presenting With Lung Metastases: A Case Report. International journal of gynecological pathology : official journal of the International Society of Gynecological Pathologists Strickland, K. C., Nucci, M. R., Esselen, K. M., Muto, M. G., Chopra, S., George, S., Howitt, B. E. 2016; 35 (1): 25-9


    We describe the case of an 81-yr-old woman who presented with bilateral pulmonary nodules in the setting of a large uterine mass, concerning for a gynecologic malignancy such as leiomyosarcoma. However, fine-needle aspiration of a lung nodule revealed a spindle cell neoplasm consistent with solitary fibrous tumor (SFT), a rare mesenchymal neoplasm characterized by a patternless architecture of spindle cells and branching ectatic vessels. Total abdominal hysterectomy demonstrated a primary SFT of the uterus. Both the lung lesion and uterine mass were positive for STAT6, a sensitive and specific biomarker for SFT. SFT infrequently metastasizes and only rarely occurs in the uterus. These tumors are considered to have uncertain malignant potential, and the diagnosis of "malignant" SFT requires the presence of >4 mitoses per 10 high-power fields. The uterine SFT we report did not meet this criterion for malignancy, emphasizing that this entity can behave aggressively even without increased mitoses or atypical histology. To our knowledge, this is the first reported case of a uterine SFT with metastasis to the lung. We discuss the differential diagnosis for the finding of multiple pulmonary spindle cell lesions in the setting of a uterine mass.

    View details for DOI 10.1097/PGP.0000000000000197

    View details for PubMedID 26107564

  • Neoepitopes and CD3-Positive and CD8-Positive Cells in Polymerase e-Mutated and Microsatellite-Instable Endometrial Cancers Reply JAMA ONCOLOGY Howitt, B. E., Shukla, S. A., Konstantinopoulos, P. A. 2016; 2 (1): 141-142

    View details for DOI 10.1001/jamaoncol.2015.3903

    View details for Web of Science ID 000383679300034

    View details for PubMedID 26767553

  • Mutational spectrum of Barrett's stem cells suggests paths to initiation of a precancerous lesion NATURE COMMUNICATIONS Yamamoto, Y., Wang, X., Bertrand, D., Kern, F., Zhang, T., Duleba, M., Srivastava, S., Khor, C., Hu, Y., Wilson, L. H., Blaszyk, H., Rolshud, D., Teh, M., Liu, J., Howitt, B. E., Vincent, M., Crum, C. P., Nagarajan, N., Ho, K., McKeon, F., Xian, W. 2016; 7: 10380


    The precancerous lesion known as Barrett's oesophagus can evolve to oesophageal adenocarcinoma in decades-long processes of regenerative growth. Here we report the isolation and propagation of distinct, patient-matched stem cells of Barrett's, gastric and oesophageal epithelia that yield divergent tumour types following in vitro transformation and xenografting. Genomic analyses reveal a broad mutational spectrum unique to Barrett's stem cells that likely reflects their risk for oncogenesis. Remarkably, 25% of cases show no cancer-related genomic changes, suggesting that Barrett's initiates without driver mutations. Most cases, however, sustain patterns of deletions almost identical to adenocarcinoma though tumour-associated gene amplifications were absent. Notably, those suspected of low-grade dysplasia have p53 mutations or undergo amplifications of proto-oncogenes and receptor tyrosine kinases, implicating these events in lethal transitions. Our findings suggest paths for the initiation and progression of Barrett's and define a discrete stem cell underlying its regenerative growth whose eradication could prevent oesophageal adenocarcinoma.

    View details for DOI 10.1038/ncomms10380

    View details for Web of Science ID 000369022100017

    View details for PubMedID 26783136

    View details for PubMedCentralID PMC4735693

  • Tumors of the Testis: Morphologic Features and Molecular Alterations. Surgical pathology clinics Howitt, B. E., Berney, D. M. 2015; 8 (4): 687-716


    This article reviews the most frequently encountered tumor of the testis; pure and mixed malignant testicular germ cell tumors (TGCT), with emphasis on adult (postpubertal) TGCTs and their differential diagnoses. We additionally review TGCT in the postchemotherapy setting, and findings to be integrated into the surgical pathology report, including staging of testicular tumors and other problematic issues. The clinical features, gross pathologic findings, key histologic features, common differential diagnoses, the use of immunohistochemistry, and molecular alterations in TGCTs are discussed.

    View details for DOI 10.1016/j.path.2015.07.007

    View details for PubMedID 26612222

  • Fine-Needle Aspiration Diagnoses of Noninvasive Follicular Variant of Papillary Thyroid Carcinoma AMERICAN JOURNAL OF CLINICAL PATHOLOGY Howitt, B. E., Chang, S., Eszlinger, M., Paschke, R., Drage, M. G., Krane, J. P., Barletta, J. A. 2015; 144 (6): 850-857


    Endocrine pathologists are reconsidering whether tumors characterized as noninvasive follicular variant of papillary thyroid carcinoma (NFVPTC) warrant a diagnosis of carcinoma. A change in terminology would affect cytology diagnoses; thus, our aim was to study the preceding fine-needle aspiration (FNA) diagnoses of this group of tumors.We evaluated the FNA diagnoses of a primary cohort of 72 consecutively resected NFVPTCs and the cytologic and molecular features of an additional cohort of 39 tumors that included both NFVPTCs and classical papillary thyroid carcinomas (cPTCs).For our primary cohort, the preceding FNA diagnosis associated with the highest risk of malignancy was suspicious for PTC in nearly half (48.6%) of cases. In contrast to the majority of cPTCs, no NFVPTCs in our second cohort had papillae or pseudoinclusions on cytologic evaluation of the FNA specimens, and none harbored a BRAF V600E mutation.If NFVPTCs were no longer termed carcinomas, this would affect the rate of malignancy of FNA diagnostic categories. Cytologic and molecular features could aid in identifying NFVPTCs at the time of FNA diagnosis.

    View details for DOI 10.1309/AJCPEIE12POICULI

    View details for Web of Science ID 000364887500005

    View details for PubMedID 26572991

  • Investigation of intratumoral heterogeneity in high-grade serous ovarian carcinoma amongst treatment naive tumors and tumors treated with neoadjuvant chemotherapy Evans, T., Howitt, B., Crum, C., Berkowitz, R., Ng, S. ACADEMIC PRESS INC ELSEVIER SCIENCE. 2015: 590-591
  • Association of Polymerase e-Mutated and Microsatellite-Instable Endometrial Cancers With Neoantigen Load, Number of Tumor-Infiltrating Lymphocytes, and Expression of PD-1 and PD-L1. JAMA oncology Howitt, B. E., Shukla, S. A., Sholl, L. M., Ritterhouse, L. L., Watkins, J. C., Rodig, S., Stover, E., Strickland, K. C., D'Andrea, A. D., Wu, C. J., Matulonis, U. A., Konstantinopoulos, P. A. 2015; 1 (9): 1319-23


    Immune checkpoint inhibitor therapy has shown benefit in various cancers, but their potential in endometrial cancer (EC) is unknown.Prediction of neoantigen load was performed using sequencing data from the Cancer Genome Atlas data set. Evaluation of tumor-infiltrating lymphocytes (TILs) and PD-1 and PD-L1 expression was performed in 63 patients with EC referred to our institution. The predicted median (range) neoantigen load (predicted neoepitopes per sample) was proportional to the mutational load: highest in ultramutated polymerase e (POLE) tumors (8342 [628-20 440]), less in hypermutated MSI (541 [146-8063]; P < .001), and lowest in microsatellite-stable tumors (70.5 [7-1877]; P < .001). The POLE and MSI ECs exhibited higher numbers of CD3+ (44.5 vs 21.8; P = .001) and CD8+ (32.8 vs 13.5; P < .001) TILs compared with microsatellite-stable tumors. PD-1 was overexpressed in TILs (81% vs 28%; P < .001) and peritumoral lymphocytes (90% vs 28%; P < .001) of POLE and MSI tumors. PD-L1 expression was infrequently noted in tumor cells but was common in intraepithelial immune cells and more frequent in POLE and MSI tumors (39% vs 13%; P = .02).Polymerase e-mutated and MSI ECs are associated with high neoantigen loads and number of TILs, which is counterbalanced by overexpression of PD-1 and PD-L1. Polymerase e-mutated and MSI EC tumors may be excellent candidates for PD-1-targeted immunotherapies.

    View details for DOI 10.1001/jamaoncol.2015.2151

    View details for PubMedID 26181000

  • Targeted genomic profiling reveals recurrent KRAS mutations and gain of chromosome 1q in mesonephric carcinomas of the female genital tract. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc Mirkovic, J., Sholl, L. M., Garcia, E., Lindeman, N., MacConaill, L., Hirsch, M., Dal Cin, P., Gorman, M., Barletta, J. A., Nucci, M. R., McCluggage, W. G., Howitt, B. E. 2015; 28 (11): 1504-14


    Mesonephric carcinoma is a rare form of gynecologic cancer derived from mesonephric remnants usually located in the lateral wall of the uterine cervix. An analogous tumor occurs in the adnexa, female adnexal tumor of probable Wolffian origin. The pathogenesis and molecular events in mesonephric carcinoma are not known. The aim of this study was to examine the molecular alterations in mesonephric carcinoma to identify driver mutations and therapeutically targetable mutations. This study consisted of 19 tumors from 17 patients: 18 mesonephric carcinomas (15 primary tumors and three metastatic tumors) and 1 female adnexal tumor of probable Wolffian origin. In two patients, both primary and metastatic tumors were available. Genomic DNA was isolated and targeted next-generation sequencing was performed to detect mutations, copy number variations, and structural variants by surveying full exonic regions of 300 cancer genes and 113 selected intronic regions across 35 genes. Fluorescence in situ hybridization (FISH) for 1p and 1q was performed in two cases. Eighty-one percent (13/16) of mesonephric carcinomas had either a KRAS (n=12) or NRAS (n=1) mutation. Mutations in chromatin remodeling genes (ARID1A, ARID1B, or SMARCA4) were present in 62% of mesonephric carcinomas. All mesonephric carcinomas lacked mutations in PIK3CA and PTEN. The most common copy number alteration was 1q gain, found in 12 (75%) mesonephric carcinomas; this was confirmed by FISH in two cases. Mesonephric carcinoma is characterized by molecular alterations that differ from those of more common variants of cervical and endometrial adenocarcinoma, which harbor KRAS/NRAS mutations in 7% and 25% of cases, respectively. KRAS/NRAS mutations are common in mesonephric carcinoma and are often accompanied by gain of 1q and mutations in chromatin remodeling genes. Targeting inhibitors of the RAS/MAPK pathway may be useful in the treatment of mesonephric carcinoma.

    View details for DOI 10.1038/modpathol.2015.103

    View details for PubMedID 26336887

  • GATA3 Is a Sensitive and Specific Marker of Benign and Malignant Mesonephric Lesions in the Lower Female Genital Tract. The American journal of surgical pathology Howitt, B. E., Emori, M. M., Drapkin, R., Gaspar, C., Barletta, J. A., Nucci, M. R., McCluggage, W. G., Oliva, E., Hirsch, M. S. 2015; 39 (10): 1411-9


    GATA3 is a transcription factor critical for embryogenesis, development, and cell differentiation. Recent studies have suggested that GATA3 is a sensitive and relatively specific biomarker for urothelial and breast carcinomas, with most Müllerian carcinomas being negative. We investigated GATA3 expression in mesonephric/Wolffian remnants and tumors in the female genital tract. A western blot was performed to assess specificity for the GATA3 antibody. GATA3 immunohistochemistry was performed on 59 formalin-fixed paraffin-embedded mesonephric samples, including 17 mesonephric remnants (MR; 11 cervical and 6 fallopian tube), 15 mesonephric hyperplasias, 21 mesonephric carcinomas, and 6 female adnexal tumors of probable Wolffian origin. Thirty conventional endocervical adenocarcinomas (ENDO-CA), 9 gastric-type cervical adenocarcinomas, and 165 endometrial adenocarcinomas (EM-CA) were also evaluated. GATA3 nuclear intensity and extent of staining was evaluated. The western blot revealed GATA3 expression in seminal vesicle and cell lines derived from breast and urothelial carcinomas, but not in other cell lines including ovarian, cervical, and endometrial cancers. All cervical MRs and mesonephric hyperplasias, 5/6 (83%) fallopian tube MRs, and 20/21 (95%) mesonephric carcinomas were GATA3 positive, although with great variability in both intensity (weak to strong) and extent (1+ to 3+) of staining. Only 1/6 (17%) female adnexal tumors of probable Wolffian origin showed weak multifocal staining. One of 30 (3%) usual-type ENDO-CAs and 3/165 EM-CAs exhibited weak-moderate GATA3 immunoreactivity; all gastric-type cervical adenocarcinomas were negative. GATA3 is a highly sensitive and specific marker for mesonephric lesions in the lower genital tract; however, its utility in the upper genital tract may be more limited. In addition, GATA3 can aid in distinguishing lower genital mesonephric lesions from usual-type and gastric-type ENDO-CAs and uterine EM-CAs.

    View details for DOI 10.1097/PAS.0000000000000471

    View details for PubMedID 26135559

  • Absence of BRAF V600E in non-infiltrative, non-invasive follicular variant of papillary thyroid carcinoma HISTOPATHOLOGY Howitt, B. E., Paulson, V. A., Barletta, J. A. 2015; 67 (4): 579-582

    View details for DOI 10.1111/his.12680

    View details for Web of Science ID 000362730400019

    View details for PubMedID 25736029

  • Carcinogenic HPV infection in the cervical squamo-columnar junction JOURNAL OF PATHOLOGY Mirkovic, J., Howitt, B. E., Roncarati, P., Demoulin, S., Suarez-Carmona, M., Hubert, P., McKeon, F. D., Xian, W., Li, A., Delvenne, P., Crum, C. P., Herfs, M. 2015; 236 (3): 265-271


    Recent studies have suggested the involvement of a unique population of cells at the cervical squamo-columnar junction (SCJ) in the pathogenesis of early (squamous intraepithelial lesion or SIL) and advanced (squamous cell and adeno-carcinomas) cervical neoplasia. However, there is little evidence to date showing that SCJ cells harbour carcinogenic HPV or are instrumental in the initial phases of neoplasia. This study was designed to (1) determine if normal-appearing SCJ cells contained evidence of carcinogenic HPV infection and (2) trace their transition to early SIL. Sections of cervix from high-risk reproductive age women were selected and SCJ cells were analysed by using several techniques which increasingly implicated HPV infection: HPV DNA (genotyping and in situ hybridization)/RNA (PCR), immunostaining for HPV16 E2 (an early marker of HPV infection), p16(ink4), Ki67, and HPV L1 protein. In 22 cases with a history of SIL and no evidence of preneoplastic lesion in the excision specimen, HPV DNA was isolated from eight of ten with visible SCJ cells, six of which were HPV16/18 DNA-positive. In five of these latter cases, the SCJ cells were positive for p16(ink4) and/or HPV E2. Transcriptionally active HPV infection (E6/E7 mRNAs) was also detected in microdissected SCJ cells. Early squamous atypia associated with the SCJ cells demonstrated in addition diffuse p16(ink4) immunoreactivity, elevated proliferative index, and rare L1 antigen positivity. We present for the first time direct evidence that normal-appearing SCJ cells can be infected by carcinogenic HPV. They initially express HPV E2 and their progression to SIL is heralded by an expanding metaplastic progeny with increased proliferation and p16(ink4) expression. Whether certain SCJs are more vulnerable than others to carcinogenic HPV genotypes and what variables determine transition to high-grade SIL remain unresolved, but the common event appears to be a vulnerable cell at the SCJ.

    View details for DOI 10.1002/path.4533

    View details for Web of Science ID 000356008700001

    View details for PubMedID 25782708

    View details for PubMedCentralID PMC4457596

  • Cloning and variation of ground state intestinal stem cells NATURE Wang, X., Yamamoto, Y., Wilson, L. H., Zhang, T., Howitt, B. E., Farrow, M. A., Kern, F., Ning, G., Hong, Y., Khor, C., Chevalier, B., Bertrand, D., Wu, L., Nagarajan, N., Sylvester, F. A., Hyams, J. S., Devers, T., Bronson, R., Lacy, D., Ho, K., Crum, C. P., McKeon, F., Xian, W. 2015; 522 (7555): 173-+


    Stem cells of the gastrointestinal tract, pancreas, liver and other columnar epithelia collectively resist cloning in their elemental states. Here we demonstrate the cloning and propagation of highly clonogenic, 'ground state' stem cells of the human intestine and colon. We show that derived stem-cell pedigrees sustain limited copy number and sequence variation despite extensive serial passaging and display exquisitely precise, cell-autonomous commitment to epithelial differentiation consistent with their origins along the intestinal tract. This developmentally patterned and epigenetically maintained commitment of stem cells is likely to enforce the functional specificity of the adult intestinal tract. Using clonally derived colonic epithelia, we show that toxins A or B of the enteric pathogen Clostridium difficile recapitulate the salient features of pseudomembranous colitis. The stability of the epigenetic commitment programs of these stem cells, coupled with their unlimited replicative expansion and maintained clonogenicity, suggests certain advantages for their use in disease modelling and regenerative medicine.

    View details for DOI 10.1038/nature14484

    View details for Web of Science ID 000356016700030

    View details for PubMedID 26040716

    View details for PubMedCentralID PMC4853906

  • Dyssynchronous Secretory Endometrial Glands Often Show Sporadically Acquired Progesterone Nonresponsiveness INTERNATIONAL JOURNAL OF GYNECOLOGICAL PATHOLOGY Howitt, B. E., Monte, N. M., Elvin, J., Mutter, G. L. 2015; 34 (3): 239-244


    Primary sporadic gene-inactivating events within the progesterone response cascade might explain the presence of individual dyssynchronous (outlier) glands commonly observed in a secretory background. We queried morphologically dyssynchronous glands in mid-secretory endometrium with a series of markers normally downregulated by progesterone. Seventy-nine mid-secretory endometrial biopsies were stained with hematoxylin and eosin, MIB-1, PAX2, estrogen and progesterone receptors, and PTEN. Aberrant staining of glands was independently scored for each marker. Outlier glands overlapping between stains were enumerated. A total of 63% of cases had hematoxylin and eosin stained outlier glands (average 9), which often demonstrated failed progesterone-mediated downregulation of PAX2 (43%), estrogen (40%), and/or progesterone receptors (28%). Aberrations of progesterone response was seen in 70% to 85% of cases overall, averaging 10 to 30 glands/affected case. The frequency and burden of affected glands was similar to that seen for primary inactivating events of the PAX2 and PTEN genes (35% and 41% of cases, respectively, averaging 32 and 38 glands per affected patient). Sporadic gene-inactivating events are common during endometrial regeneration, and may cause morphologic changes unmasked by the hormonal context. Some of these dyssynchronous "outlier" glands, whether evident on hematoxylin and eosin stain or not, have an interrupted progesterone response.

    View details for DOI 10.1097/PGP.0000000000000157

    View details for Web of Science ID 000352640800005

    View details for PubMedID 25844547

  • Primary Myxoid Liposarcoma of the Ovary in a Postpartum Female: A Case Report and Review of Literature INTERNATIONAL JOURNAL OF GYNECOLOGICAL PATHOLOGY Liang, S. X., Howitt, B., Blitz, M. J., Bhuiya, T., Thamasebi, F., Sternchos, J., Shih, K. 2015; 34 (3): 298-302


    A 36-year-old gravida 4, para 2 African-American woman, presented at three months postpartum with a right ovarian mass identified on a lumbar spine MRI as part of a neurology workup for persistent lower back pain. A follow-up pelvic ultrasound noted a 7.0 × 6.1 × 3.8 cm septated mixed cystic and solid mass. Exploratory laparoscopy and right ovarian cystectomy yielded a final pathologic diagnosis of intermediate grade myxoid liposarcoma, confirmed with DDIT3 gene rearrangement studies.

    View details for DOI 10.1097/PGP.0000000000000145

    View details for Web of Science ID 000352640800014

    View details for PubMedID 25760901

  • Evidence for a dualistic model of high-grade serous carcinoma: BRCA mutation status, histology, and tubal intraepithelial carcinoma. The American journal of surgical pathology Howitt, B. E., Hanamornroongruang, S., Lin, D. I., Conner, J. E., Schulte, S., Horowitz, N., Crum, C. P., Meserve, E. E. 2015; 39 (3): 287-93


    Most early adnexal carcinomas detected in asymptomatic women with germline BRCA mutations (BRCA) present as serous tubal intraepithelial carcinomas (STIC). However, STICs are found in only ∼40% of symptomatic high-grade serous carcinomas (HGSCs) and less frequently in pseudoendometrioid variants of HGSC. Consecutive cases of untreated HGSC from BRCA and BRCA women with detailed fallopian tube examination (SEE-FIM protocol) were compared. STIC status (+/-) was determined, and tumors were classified morphologically as SET ("SET", >50% solid, pseudoendometrioid, or transitional) or classic predominate ("Classic"). SET tumors trended toward a higher frequency in BRCA versus BRCA women (50% vs. 28%, P=0.11), had a significantly younger mean age than those with classic HGSC in BRCA women (mean 56.2 vs. 64.8 y, P=0.04), and displayed a better clinical outcome in both groups combined (P=0.024). STIC was significantly more frequent in tumors from the BRCA cohort (66% vs. 31%, P=0.017) and specifically the BRCA tumors with classic morphology (83%) versus those with SET morphology (22%, P=0.003). Overall, several covariables-histology, BRCA status, age, coexisting STIC, and response to therapy-define 2 categories of HGSC with differences in precursor (STIC) frequency, morphology, and outcome. We introduce a dualistic HGSC model that could shed light on the differences in frequency of STIC between symptomatic and asymptomatic women with HGSC. This model emphasizes the need for further study of HGSC precursors to determine their relevance to the prevention of this lethal malignancy.

    View details for DOI 10.1097/PAS.0000000000000369

    View details for PubMedID 25581732

  • Inflammatory myofibroblastic tumor of the uterus: clinical and pathologic review of 10 cases including a subset with aggressive clinical course. The American journal of surgical pathology Parra-Herran, C., Quick, C. M., Howitt, B. E., Dal Cin, P., Quade, B. J., Nucci, M. R. 2015; 39 (2): 157-68


    Inflammatory myofibroblastic tumor is currently regarded as a neoplasm with intermediate biological potential and a wide anatomic distribution. Inflammatory myofibroblastic tumors of the female genital tract are rare, and to date reported cases behaved indolently. We describe, herein, 10 cases of uterine inflammatory myofibroblastic tumor, 3 of which had an aggressive clinical course. Subject age ranged from 29 to 73 years. Tumors were composed of spindle and epithelioid myofibroblastic cells admixed with lymphoplasmacytic infiltrates in a variably myxoid stroma. Two growth patterns, myxoid and fascicular (leiomyoma-like), were noted. All tumors were positive for ALK expression by immunohistochemistry, which was stronger in the myxoid areas. Smooth muscle marker and CD10 expression was variable in extent, but typically positive. Fluorescence in situ hybridization for ALK rearrangements was positive in both fascicular and myxoid areas in all 8 cases tested. Three subjects showed clinical evidence of tumor aggressiveness as defined by extrauterine spread, local recurrence, or distant metastasis. Aggressive tumors were larger, had a higher proportion of myxoid stroma, and higher mitotic activity than indolent tumors. Tumor cell necrosis was seen only in cases with adverse outcome. This is the first report to describe aggressive biological behavior in uterine inflammatory myofibroblastic tumor. This diagnosis is often underappreciated and merits inclusion in the differential diagnosis of myxoid mesenchymal lesions of the uterus, particularly because patients with an aggressive course may benefit from targeted therapy.

    View details for DOI 10.1097/PAS.0000000000000330

    View details for PubMedID 25321329

  • Many postchemotherapy sarcomatous tumors in patients with testicular germ cell tumors are sarcomatoid yolk sac tumors: a study of 33 cases. The American journal of surgical pathology Howitt, B. E., Magers, M. J., Rice, K. R., Cole, C. D., Ulbright, T. M. 2015; 39 (2): 251-9


    Sarcomatoid neoplasms in patients with testicular germ cell tumors (TGCTs) may show diverse lineages and are usually attributed to "transformation" of teratoma, although origin from yolk sac tumor (YST) has also been suggested. We evaluated 33 sarcomatoid tumors from 23 TGCT patients that lacked specific features of a defined sarcoma subtype for a number of features, including: atypia (mild, moderate, severe), cellularity, tumor necrosis, mitotic index, stromal vascularity, cell profile (spindle or epithelioid), and stromal quality (myxoid and/or fibrous). Immunohistochemical staining analyses directed against cytokeratin (AE1/AE3), SALL4, glypican-3 (GPC3), α-fetoprotein (AFP), p63, glial fibrillary acidic protein (GFAP), CD34, MUC4, smooth muscle actin (SMA), desmin, caldesmon, and myogenin were performed. Staining intensity (0=negative, 1=weak, 2=moderate, 3=strong) and extent (0=<1%, 1=1% to 10%, 2=10% to 50%, 3=>50%) were scored. Tumor grade based on the French sarcoma grading system was assessed, with grades 2-3 considered high grade. Tumors with at least moderate intensity and >10% (+) cells for both AE1/AE3 and GPC3 were considered to be sarcomatoid YST (SYST); 22 tumors from 14 patients (ages 18 to 38 y, mean 27 y) met these criteria and were the focus of this study. All SYSTs occurred after chemotherapy (3 to 132 mo after TGCT diagnosis; mean 42.5 mo, median 30.5 mo). They had spindled (100%; 19 predominant) and epithelioid cells (77%; 3 predominant) in myxoid to fibrous stroma. Thirteen exhibited at least focally severe nuclear atypia. Distinctive tumor "ringlets" and intercellular basement membrane deposits (parietal YST differentiation) were common. In addition to positivity for AE1/AE3 and GPC3, 15/22 were SALL4 (+), 10/22 were at least focally CD34 (+), and 2/22 were focally p63 (+). Fifty percent exhibited smooth muscle differentiation as evidenced by desmin (8/19), caldesmon (2/4), and/or SMA (4/6) reactivity. AFP, MUC4, GFAP, and myogenin were negative in all cases. On follow-up, 8/14 patients died of disease at 7 to 217 months (mean 58 mo) after the initial SYST diagnosis, whereas 5/14 were alive and had no evidence of disease (ANED) at 1 to 259 months (mean 83 mo). One patient died of unrelated causes at 39 months. Of the 11 patients with high-grade tumors, 8 were dead of disease, 1 died of an unrelated cause, and 2 were ANED; all 3 patients with low-grade tumors were ANED at 41 to 262 months (mean 128 mo). We conclude that a high proportion of sarcomatoid tumors in postchemotherapy resections of TGCT patients are SYSTs. These typically occur several years after diagnosis and behave aggressively when high grade.

    View details for DOI 10.1097/PAS.0000000000000322

    View details for PubMedID 25229769

  • Targeted genomic analysis of Müllerian adenosarcoma. The Journal of pathology Howitt, B. E., Sholl, L. M., Dal Cin, P., Jia, Y., Yuan, L., MacConaill, L., Lindeman, N., Kuo, F., Garcia, E., Nucci, M. R., Quade, B. J. 2015; 235 (1): 37-49


    Müllerian adenosarcoma (MA) is a rare mixed mesenchymal tumour of the female genital tract, composed of malignant stroma and benign-appearing epithelium. Sarcomatous overgrowth (SO) is the only established histological variable associated with higher stage and shorter survival. Specific molecular or immunohistochemistry (IHC) tools for the diagnosis of MA are lacking. Our goal was to study genomic mutations and copy number variations (CNVs) in MA to understand better its pathobiology, and develop specific diagnostic and prognostic tools. DNA was extracted from 20 samples of MA from 18 subjects (12 without SO and 6 with SO), including two in which areas of both typical MA histology and SO were independently tested. Samples were analysed using a targeted next-generation sequencing assay interrogating exonic sequences of 275 cancer genes for mutations and CNVs as well as 91 introns across 30 genes for cancer-associated rearrangements. The mean number of mutations in MA with SO (mean 9.7; range 3-14) did not differ significantly from that in MA without SO (mean 9.6; range 5-16). MA with SO had significantly higher mean numbers of gene-level CNVs (24.6) compared to MA without SO (5; p = 0.0002). The most frequent amplification involved MDM2 and CDK4 (5/18; 28%), accompanied by focal CDK4 and MDM2 and diffuse HMGA2 expression using immunohistochemistry. MYBL1 amplification was seen in 4/18 (22%), predominantly in SO. Alterations in PIK3CA/AKT/PTEN pathway members were seen in 13/18 (72%). Notably, TP53 mutations were uncommon, present in only two cases with SO. Three out of 18 (17%) had mutations in ATRX, all associated with SO. No chromosomal rearrangements were identified. We have identified a number of recurrent genomic alterations in MA, including some associated with SO. Although further investigation of these findings is needed, confirmation of one or more may lead to new mechanistic insights and novel markers for this often difficult-to-diagnose tumour.

    View details for DOI 10.1002/path.4442

    View details for PubMedID 25231023

  • Uterine polyps with features overlapping with those of Müllerian adenosarcoma: a clinicopathologic analysis of 29 cases emphasizing their likely benign nature. The American journal of surgical pathology Howitt, B. E., Quade, B. J., Nucci, M. R. 2015; 39 (1): 116-26


    Müllerian adenosarcoma (MA) is a mixed Müllerian neoplasm composed of malignant stroma and benign epithelium. Endometrial and endocervical polyps are common entities in surgical pathology practice and most can be readily distinguished from MA; however, some have overlapping features, causing diagnostic confusion. In this study, we examined uterine polyps falling short of the diagnosis of MA quantitatively, qualitatively, or both. Our aims were to (1) characterize formally the morphologic features of atypical uterine polyps and (2) determine clinical outcome. Cases were evaluated for morphologic features of MA (phyllodes-like architecture, intraglandular polypoid projections, altered periglandular stroma, and stromal cytologic atypia), and the maximum number of mitoses per 10 high-power fields. The percentage involvement within a polyp by any atypical feature was estimated. The most common change was abnormal architecture, although periglandular stromal abnormalities and increased mitoses were also frequent findings. Stromal cytologic atypia was rare and when present was focal and mild. Histologic follow-up was performed in 24/29 (86%). Two patients had uterine polyps with unusual features similar to those noted on the initial biopsy. The remainder showed either polyp without unusual features or no residual polyp. Clinical follow-up information was available for 28/29 (97%). Twenty-seven of 28 were alive without evidence of disease, whereas 1 patient had died of pancreatic adenocarcinoma. We have shown that uterine polyps with features overlapping with those of MA have a benign clinical course, even with conservative management, as no cases showed progression or malignant transformation.

    View details for DOI 10.1097/PAS.0000000000000303

    View details for PubMedID 25118811

  • The PAX2-null immunophenotype defines multiple lineages with common expression signatures in benign and neoplastic oviductal epithelium JOURNAL OF PATHOLOGY Ning, G., Bijron, J. G., Yamamoto, Y., Wang, X., Howitt, B. E., Herfs, M., Yang, E., Hong, Y., Cornille, M., Wu, L., Hanamornroongruang, S., McKeon, F. D., Crum, C. P., Xian, W. 2014; 234 (4): 478-487


    The oviducts contain high-grade serous cancer (HGSC) precursors (serous tubal intraepithelial neoplasia or STINs), which are γ-H2AX(p) - and TP53 mutation-positive. Although they express wild-type p53, secretory cell outgrowths (SCOUTs) are associated with older age and serous cancer; moreover, both STINs and SCOUTs share a loss of PAX2 expression (PAX2(n) ). We evaluated PAX2 expression in proliferating adult and embryonic oviductal cells, normal mucosa, SCOUTs, Walthard cell nests (WCNs), STINs, and HGSCs, and the expression of genes chosen empirically or from SCOUT expression arrays. Clones generated in vitro from embryonic gynaecological tract and adult Fallopian tube were Krt7(p) /PAX2(n) /EZH2(p) and underwent ciliated (PAX2(n) /EZH2(n) /FOXJ1(p) ) and basal (Krt7(n) /EZH2(n) /Krt5(p) ) differentiation. Similarly, non-ciliated cells in normal mucosa were PAX2(p) but became PAX2(n) in multi-layered epithelium undergoing ciliated or basal (WCN) cell differentiation. PAX2(n) SCOUTs fell into two groups: type 1 were secretory or secretory/ciliated with a 'tubal' phenotype and were ALDH1(n) and β-catenin(mem) (membraneous only). Type 2 displayed a columnar to pseudostratified (endometrioid) phenotype, with an EZH2(p) , ALDH1(p) , β-catenin(nc) (nuclear and cytoplasmic), stathmin(p) , LEF1(p) , RCN1(p) , and RUNX2(p) expression signature. STINs and HGSCs shared the type 1 immunophenotype of PAX2(n) , ALDH1(n) , β-catenin(mem) , but highly expressed EZH2(p) , LEF1(p) , RCN1(p) , and stathmin(p) . This study, for the first time, links PAX2(n) with proliferating fetal and adult oviductal cells undergoing basal and ciliated differentiation and shows that this expression state is maintained in SCOUTs, STINs, and HGSCs. All three entities can demonstrate a consistent perturbation of genes involved in potential tumour suppressor gene silencing (EZH2), transcriptional regulation (LEF1), regulation of differentiation (RUNX2), calcium binding (RCN1), and oncogenesis (stathmin). This shared expression signature between benign and neoplastic entities links normal progenitor cell expansion to abnormal and neoplastic outgrowth in the oviduct and exposes a common pathway that could be a target for early prevention.

    View details for DOI 10.1002/path.4417

    View details for Web of Science ID 000344797400006

    View details for PubMedID 25130537

    View details for PubMedCentralID PMC4229427

  • Decidualized Endometrioma Masquerading as Ovarian Cancer in Pregnancy JOURNAL OF ULTRASOUND IN MEDICINE Groszmann, Y., Howitt, B. E., Bromley, B., Feltmate, C. M., Benacerraf, B. R. 2014; 33 (11): 1909-1915


    To identify the sonographic features of decidualized endometriomas in patients treated at a single institution and to determine whether sonographic findings can distinguish these lesions from malignant ovarian tumors during pregnancy.We conducted a retrospective cohort study that included pregnant women with a histologic diagnosis of decidualized endometrioma between January 1, 2005, and December 1, 2012, and had an ovarian cyst or mass seen preoperatively on obstetrical sonography. Sonographic characteristics of these masses were retrospectively evaluated using the International Ovarian Tumor Analysis Group definitions for adnexal masses.Seventeen patients with 22 adnexal masses were included in our study. Nine of 22 lesions (41%) were classified as unilocular solid, and 14 of 22 (64%) had solid components, of which 12 of 14 (86%) had substantial blood flow. Septations were present in 8 of 22 masses (36%). Cyst sizes varied from 30 to 120 and 32 to 270 mm at the initial and follow-up scans, respectively. Eight patients had no follow-up scans and underwent surgery within 3 weeks of diagnosis. The other 9 patients (14 masses), had follow-up scans and underwent surgery from 3 to 34 weeks after their initial scans. Eight of these masses showed no notable change in size or appearance, and 1 became smaller.There were no characteristic sonographic features identified to distinguish decidualized endometrioma from ovarian malignancy. However, lesions showing no change in size over 4 weeks or lacking solid components and vascularity are more likely to be benign rather than malignant and may justify delaying surgery until delivery or postpartum.

    View details for DOI 10.7863/ultra.33.11.1909

    View details for Web of Science ID 000343794400004

    View details for PubMedID 25336477

  • Perivascular epithelioid cell neoplasm (PEComa) of the gynecologic tract: clinicopathologic and immunohistochemical characterization of 16 cases. The American journal of surgical pathology Schoolmeester, J. K., Howitt, B. E., Hirsch, M. S., Dal Cin, P., Quade, B. J., Nucci, M. R. 2014; 38 (2): 176-88


    Perivascular epithelioid cell tumor (PEComa) belongs to a family of tumors characterized by coexpression of melanocytic and muscle markers. Recent studies have shown that sporadic and tuberous sclerosis complex-associated PEComa may respond to mTOR inhibitors underscoring the importance of recognizing this tumor. However, its occurrence in the gynecologic tract continues to be disputed owing to its common misclassification as other types of uterine sarcoma and its controversial relationship with epithelioid smooth muscle tumors. To more fully characterize PEComa of the female genital tract, 16 cases of gynecologic PEComa were identified (1990 to 2012) and formed the basis of this study. Each case was analyzed for conventional morphologic and immunohistochemical characteristics established for PEComa of extrauterine sites; clinical outcome data were obtained for all cases. The 16 patients were aged 28 to 60 (mean 49; median 50) years, and 1 had a history of tuberous sclerosis complex. Thirteen cases were primary of the uterus, 2 of the adnexa, and 1 of the vagina. Tumor size ranged from 0.3 to 25.0 (mean 8.7) cm. Three patients died of disease, 6 were alive with disease, and 7 were alive without evidence of disease at last follow-up (1 mo to 13 y follow-up; mean 26 mo). All patients with an adverse outcome met established criteria for malignancy as proposed for extrauterine sites (ie, 2 or more features present: size ≥5 cm, high-grade nuclear features, infiltration, necrosis, lymphovascular invasion, or a mitotic rate ≥1/50 high-power fields). Of the melanocytic markers, HMB45 was most commonly expressed (16/16 positive, 100%), followed by microphthalmia transcription factor (11/12 positive, 92%), MelanA (14/16 positive, 88%), and S100 protein (2/10 positive, 20%). Of the smooth muscle markers, desmin was most commonly expressed (15/15 cases, 100%), followed by SMA (14/15 cases, 93%) and h-caldesmon (11/12 cases, 92%). TFE3 immunopositivity was identified in 5 of 13 cases; however, 3 tested cases were negative for a TFE3 rearrangement by fluorescence in situ hybridization. Current criteria for malignancy appear to be valid in the female genital tract, although modified criteria, as described herein, may be more specific. Awareness of the characteristic features of PEComa is important to help distinguish it from epithelioid smooth muscle tumors and other mimics as PEComa may respond to unique chemotherapeutic regimens.

    View details for DOI 10.1097/PAS.0000000000000133

    View details for PubMedID 24418852

  • Through the glass darkly: intraepithelial neoplasia, top-down differentiation, and the road to ovarian cancer. The Journal of pathology Crum, C. P., Herfs, M., Ning, G., Bijron, J. G., Howitt, B. E., Jimenez, C. A., Hanamornroongruang, S., McKeon, F. D., Xian, W. 2013; 231 (4): 402-12


    It is currently hoped that deaths from extra-uterine high-grade serous cancer (HGSC) will be reduced via opportunistic salpingectomy in healthy women. Accumulated data implicate the fimbria as a site of origin and descriptive molecular pathology and experimental evidence strongly support a serous carcinogenic sequence in the Fallopian tube. Both direct and indirect ('surrogate') precursors suggest that the benign tube undergoes important biological changes after menopause, acquiring abnormalities in gene expression that are often shared with malignancy, including PAX2, ALDH1, LEF1, RCN1, RUNX2, beta-catenin, EZH2, and others. However, the tube can be linked to only some HGSCs, recharging arguments that nearby peritoneum/ovarian surface epithelium (POSE) also hosts progenitors to this malignancy. A major sticking point is the difference in immunophenotype between POSE and Müllerian epithelium, essentially requiring mesothelial to Müllerian differentiation prior to or during malignant transformation to HGSC. However, emerging evidence implicates an embryonic or progenitor phenotype in the adult female genital tract with the capacity to differentiate, normally or during neoplastic transformation. Recently, a putative cell of origin for cervical cancer has been identified in the squamo-columnar (SC) junction, projecting a model whereby Krt7+ embryonic progenitors give rise to immunophenotypically distinct progeny under stromal influences via 'top down' differentiation. Similar differentiation can be seen in the endometrium with a parallel in juxtaposed mesothelial and Müllerian differentiation in the ovary. Abrupt mesothelial-Müllerian transitions remain to be proven, but would explain the rapid evolution, short asymptomatic interval, and absence of a defined epithelial starting point in many HGSCs. Resolving this question will require accurately distinguishing progenitor from progeny tumour cells in HGSC and pinpointing where initial transformation and trans-differentiation occur, whether in the tube or POSE. Both will be critical to expectations from prophylactic salpingectomy and future approaches to pelvic serous cancer prevention.

    View details for DOI 10.1002/path.4263

    View details for PubMedID 24030860

    View details for PubMedCentralID PMC3947463

  • Oncogenic mutations in cervical cancer: genomic differences between adenocarcinomas and squamous cell carcinomas of the cervix. Cancer Wright, A. A., Howitt, B. E., Myers, A. P., Dahlberg, S. E., Palescandolo, E., Van Hummelen, P., MacConaill, L. E., Shoni, M., Wagle, N., Jones, R. T., Quick, C. M., Laury, A., Katz, I. T., Hahn, W. C., Matulonis, U. A., Hirsch, M. S. 2013; 119 (21): 3776-83


    Cervical cancer is the second leading cause of cancer deaths among women worldwide. The objective of this study was to describe the most common oncogenic mutations in cervical cancers and to explore genomic differences between the 2 most common histologic subtypes: adenocarcinoma and squamous cell carcinoma.A high-throughput genotyping platform, termed Oncomap, was used to interrogate 80 cervical tumors for 1250 known mutations in 139 cancer genes. Samples were analyzed using a mass spectrometry-based genotyping platform and were validated using orthogonal chemistry. Epidermal growth factor receptor (EGFR) mutations were further validated by massive parallel sequencing. Human papilloma virus (HPV) genotyping also was performed.Validated mutations were detected in 48 of 80 tumors (60%) examined. The highest mutation rates were in the genes phosphatidylinositol 3-kinase, catalytic subunit α (PIK3CA) (31.3%); Kirsten rat sarcoma viral oncogene homolog (KRAS) (8.8%); and EGFR (3.8%). PIK3CA mutation rates did not differ significantly between adenocarcinomas and squamous cell carcinomas (25% vs 37.5%, respectively; P = .33). In contrast, KRAS mutations were identified only in adenocarcinomas (17.5% vs 0%; P = .01), and a novel EGFR mutation was detected only in squamous cell carcinomas (0% vs 7.5%; P = .24). There were no associations between HPV-16 or HPV-18 and somatic mutations or overall survival. In adjusted analyses, PIK3CA mutations were associated with shorter survival (67.1 months vs 90.3 months; hazard ratio, 9.1; 95% confidence interval, 2.8-29.5 months; P < .001).Cervical cancers harbor high rates of potentially targetable oncogenic mutations. In addition, cervical squamous cell carcinoma and adenocarcinoma have distinct molecular profiles, suggesting that clinical outcomes may be improved with the use of more tailored treatment strategies, including PI3K and MEK inhibitors.

    View details for DOI 10.1002/cncr.28288

    View details for PubMedID 24037752

    View details for PubMedCentralID PMC3972000

  • Identification and Characterization of 2 Testicular Germ Cell Markers, Glut3 and CyclinA2 APPLIED IMMUNOHISTOCHEMISTRY & MOLECULAR MORPHOLOGY Howitt, B. E., Brooks, J. D., Jones, S., Higgins, J. P. 2013; 21 (5): 401-407


    Testicular germ cell tumors (TGCT) are the most common type of testicular tumor and encompass different histologic types that greatly influence treatment and prognosis. Immunohistochemical studies may be required for accurate classification, particularly when these tumors present at extragonadal sites, and to aid in distinguishing histologic types. Traditional markers for identifying and distinguishing TGCT include PLAP, CD117, AFP, and CD30. More recently, the addition of OCT3/4 and SALL4 has increased sensitivity for immunohistochemical detection of germ cell tumors. We examined gene expression data from a previously published microarray study that compared normal testis mRNA expression to various TGCT. We also performed a search of the literature to identify less well-characterized markers. Glut3 and cyclinA2 showed promise as TGCT markers. Therefore, we evaluated expression of glut3 and cyclinA2 by immunohistochemistry using tissue microarrays (TMAs). Of 66 seminomas included in the TMA, 64 (97%) showed positive nuclear staining for cyclinA2 and 58 (88%) were strongly positive. Strong positive staining for cyclinA2 was also seen in the spermatocytic seminoma. All 20 of the embryonal carcinomas stained positively with cyclinA2, and 19 (95%) displayed strong nuclear staining for cyclinA2. Twenty of the 20 embryonal carcinomas stained for glut3 in a strong membranous pattern. Of 8 yolk sac tumors, 100% stained with glut3. We also evaluated glut3 and cyclinA2 staining on a general TMA containing 486 samples representing 156 different tumors. CyclinA2 stained a number of other tumor types, but the majority of these were weak or focal staining. Glut3 was rarely positive in other tumors; interestingly, most of these were of ovarian origin. We conclude that glut3 is a sensitive (96%) and specific (92%) marker for embryonal carcinomas and yolk sac tumors. Although cyclinA2 is a sensitive marker of seminomas and embryonal carcinomas (98%), its specificity is lower if focal and weak staining of nongerm cell tumors is considered positive. The sensitivity and specificity of glut3 are comparable with that seen for SALL4.

    View details for DOI 10.1097/PAI.0b013e31827b505f

    View details for Web of Science ID 000324837800004

    View details for PubMedID 23343953

  • Molecular Alterations in Partially-Encapsulated or Well-Circumscribed Follicular Variant of Papillary Thyroid Carcinoma THYROID Howitt, B. E., Jia, Y., Sholl, L. M., Barletta, J. A. 2013; 23 (10): 1256-1262


    Studies have described an encapsulated and an infiltrative form of the follicular variant of papillary thyroid carcinoma (FVPTC). Encapsulated FVPTCs have been reported to have virtually no recurrence risk or metastatic potential and to harbor RAS mutations but not BRAF mutations. In contrast, infiltrative tumors have significant metastatic potential, a risk of recurrence, and a BRAF mutation frequency of approximately 25%. In our experience, a substantial number of FVPTCs are neither fully encapsulated nor infiltrative, but instead are partially encapsulated (PE) or well circumscribed (WC). We have previously reported that PE/WC FVPTCs behave in an indolent fashion similar to encapsulated tumors. The purpose of the current study was to evaluate the molecular alterations in PE/WC FVPTC.We identified 28 PE/WC FVPTCs resected consecutively at our institution. Targeted mutation analysis of 41 genes including members of the RAS and RAF families was performed on DNA extracted from formalin-fixed, paraffin-embedded blocks using single-base extension chemistry and mass spectrometry.Lymph node metastases were absent in all cases with sampled lymph nodes, and no patients developed tumor recurrences (median follow-up time, 72.8 months). Overall, 13 cases (46%) harbored RAS mutations, including seven (25%) with NRAS mutations (p.Gln61Arg) and six (21%) with HRAS mutations (five had p.Gln61Arg and one had a p.Gln61Lys substitution). No PE/WC FVPTCs had BRAF mutations.The results of this study confirm our previous finding that PE/WC FVPTCs pursue an indolent clinical course. Additionally, we found that PE/WC tumors have a similar molecular profile to that of encapsulated FVPTCs with frequent RAS mutations (46%) and no BRAF mutations. These molecular results provide further evidence that PE/WC and encapsulated FVPTCs are biologically similar and should be distinguished from more aggressive infiltrative FVPTCs.

    View details for DOI 10.1089/thy.2013.0018

    View details for Web of Science ID 000324832100011

    View details for PubMedID 23477374

  • Cervical Squamocolumnar Junction-specific Markers Define Distinct, Clinically Relevant Subsets of Low-grade Squamous Intraepithelial Lesions AMERICAN JOURNAL OF SURGICAL PATHOLOGY Herfs, M., Parra-Herran, C., Howitt, B. E., Laury, A. R., Nucci, M. R., Feldman, S., Jimenez, C. A., McKeon, F. D., Xian, W., Crum, C. P. 2013; 37 (9): 1311-1318


    Low-grade cervical squamous abnormalities (low-grade squamous intraepithelial lesions [LSIL, CIN1]) can be confused with or followed by high-grade (HSIL, CIN2/3) lesions, expending considerable resources. Recently, a cell of origin for cervical neoplasia was proposed in the squamocolumnar junction (SCJ); HSILs are almost always SCJ, but LSILs include SCJ and SCJ subsets. Abnormal cervical biopsies from 214 patients were classified by 2 experienced pathologists (panel) as LSIL or HSIL using published criteria. SILs were scored SCJ and SCJ using SCJ-specific antibodies (keratin7, AGR2, MMP7, and GDA). Assessments of interobserver agreement, p16 staining pattern, proliferative index, and outcome were compared. The original diagnostician agreed with the panel diagnosis of HSIL and SCJ LSIL in all cases (100%). However, for SCJ LSIL, panelists disagreed with each other by 15% and with the original diagnostician by 46.2%. Comparing SCJ and SCJ LSILs, 60.2% and 94.9% were p16 positive, 23% and 74.4% showed strong (full-thickness) p16 staining, and 0/54 (0%) and 8/33 (24.2%) with follow-up had an HSIL outcome, respectively. Some SCJ LSILs are more likely to both generate diagnostic disagreement and be associated with HSIL. Conversely, SCJ LSILs generate little observer disagreement and, when followed, have a very low risk of HSIL outcome. Thus, SCJ biomarkers in conjunction with histology may segregate LSILs with very low risk of HSIL outcome and conceivably could be used as a management tool to reduce excess allocation of resources to the follow-up of these lesions.

    View details for Web of Science ID 000330429800002

    View details for PubMedID 24076771

    View details for PubMedCentralID PMC3905241

  • Intestinal-type endocervical adenocarcinoma in situ: an immunophenotypically distinct subset of AIS affecting older women. The American journal of surgical pathology Howitt, B. E., Herfs, M., Brister, K., Oliva, E., Longtine, J., Hecht, J. L., Nucci, M. R. 2013; 37 (5): 625-33


    Conventional endocervical adenocarcinoma in situ (cAIS) is typically strongly and diffusely positive for p16 with a high Ki67 index consistent with its frequent association with high-risk human papillomavirus (HPV) infection. The intestinal variant (iAIS) is less common, and its relationship to HPV infection has not been thoroughly examined. This study compares the clinicopathologic features, frequency of HPV infection, and expression of CDX2 and surrogate biomarkers of HPV infection (p16, Ki67) in cAIS with those of iAIS. A total of 86 cases with a diagnosis of AIS (49 iAIS, 37 cAIS) were identified from our multi-institutional files. Of these, 13 iAIS and 20 cAIS cases had slides and tissue available for histopathologic review, immunohistochemical analysis, and molecular tests. All 86 cases were used to evaluate clinical parameters; however, HPV DNA analysis and immunohistochemical analysis for p16, MIB-1, CDX2, and p53 were performed only on those cases with available slides or paraffin blocks. The average age at diagnosis was significantly higher in iAIS compared with that in cAIS (44.5 vs. 32.6 y) (P=0.0001). All 20 cAIS cases showed moderate to strong and diffuse p16 staining; however, only 9/13 iAIS cases showed this degree of p16 staining, whereas 4/13 (31%) iAIS cases showed weak and patchy distribution (P<0.02). Only 6/9 (67%) iAIS cases were positive for either HPV type 18 (5) or 33 (1), in contrast to 11/11 conventional cAIS (P=0.04). Similarly, 12/14 cAIS, but only 5/13 iAIS, cases showed a high Ki67 proliferative index. CDX2 was positive in all iAIS cases, whereas p53 was negative. Most iAIS cases are positive for high-risk HPV and show moderate to strong and diffuse p16 staining; however, a subset of iAIS shows variable staining with p16 and Ki67, is not associated with HPV, and occurs in a distinctly older age group suggesting an alternative pathogenesis. Awareness that iAIS can show variable staining for p16 and Ki67 is important when resolving problematic endocervical lesions, particularly in small biopsies with unusual p16 staining patterns.

    View details for DOI 10.1097/PAS.0b013e318285be00

    View details for PubMedID 23552379

  • A novel blueprint for 'top down' differentiation defines the cervical squamocolumnar junction during development, reproductive life, and neoplasia. The Journal of pathology Herfs, M., Vargas, S. O., Yamamoto, Y., Howitt, B. E., Nucci, M. R., Hornick, J. L., McKeon, F. D., Xian, W., Crum, C. P. 2013; 229 (3): 460-8


    The cervical squamocolumnar (SC) junction is the site of a recently discovered 'embryonic' cell population that was proposed as the cell of origin for cervical cancer and its precursors. How this population participates in cervical remodelling and neoplasia is unclear. In the present study, we analysed the SC junction immunophenotype during pre- and post-natal human and mouse development and in the adult, processes of metaplastic evolution of the SC junction, microglandular change, and early cervical neoplasia. Early in life, embryonic cervical epithelial cells were seen throughout the cervix and subsequently diminished in number to become concentrated at the SC junction in the adult. In all settings, there was a repetitive scenario in which cuboidal embryonic/SC junction cells gave rise to subjacent metaplastic basal/reserve cells with a switch from the SC junction positive to negative immunophenotype. This downward or basal (rather than upward or apical) evolution from progenitor cell to metaplastic progeny was termed reverse or 'top down' differentiation. A similar pattern was noted in high-grade squamous intraepithelial lesions (HSILs), suggesting that HPV infection of the cuboidal SC junction cells initiated outgrowth of basally-oriented neoplastic progeny. The progressive loss of the embryonic/SC junction markers occurred with 'top down' differentiation during development, remodelling, and early neoplasia. Interestingly, most low-grade SILs were SC junction-negative, implying infection of metaplastic progeny rather than the original SC junction cells. This proposed model of 'top down' differentiation resolves the mystery of how SC junction cells both remodel the cervix and participate in neoplasia and provides for a second population of metaplastic progeny (including basal and reserve cells), the infection of which is paradoxically less likely to produce a biologically aggressive precursor. It also provides new targets in animal models to determine why the SC junction is uniquely susceptible to carcinogenic HPV infection.

    View details for DOI 10.1002/path.4110

    View details for PubMedID 23007879

  • Stathmin-1 expression as a complement to p16 helps identify high-grade cervical intraepithelial neoplasia with increased specificity. The American journal of surgical pathology Howitt, B. E., Nucci, M. R., Drapkin, R., Crum, C. P., Hirsch, M. S. 2013; 37 (1): 89-97


    A fundamental controversy in using biomarkers to diagnose cervical cancer precursors [ie, squamous intraepithelial lesions (SIL)] is their lack of specificity for high-grade SIL [HSIL; cervical intraepithelial neoplasia grade 2/3 (CIN2/3)]. Stathmin-1 (STMN), a microtubule-destabilizing protein important in mitosis, is overexpressed in a variety of malignancies including those from the Müllerian tract and may be associated with poor outcome. However, the use of STMN as a diagnostic marker in cervical SILs has not been explored. A total of 193 cervical samples, including benign cervix and squamous and glandular lesions, were evaluated for STMN, p27 (a known cell cycle regulator inversely expressed with STMN in normal and many neoplastic tissues), p16, and Ki67 expression by immunohistochemical analysis. SILs were independently scored and classified as benign, low-grade SIL (LSIL/CIN1), and HSIL (separated into CIN2 or CIN3) on the basis of a majority diagnosis. Each diagnosis was correlated with biomarker expression independent of hematoxylin and eosin review. STMN was normally expressed in basal cells of the ectocervix and was absent in benign endocervix;"positive" STMN staining was defined as immunoreactivity in at least two thirds of the epithelial thickness. A majority hematoxylin and eosin diagnosis was obtained in 189/193 cases on initial independent review, with squamous epithelia ultimately classified as benign, CIN1, CIN2, and CIN3 in 25, 56, 11, and 16 cases, respectively. STMN was positive in 5/56 (9%) CIN1, 5/11 (45%) CIN2, 14/15 (93%) CIN3, all adenocarcinoma in situ (19/19), and all invasive squamous cell carcinoma (32/32) and adenocarcinoma (34/34) cases. In contrast, 40/56 (71%) CIN1, 11/11 (100%) CIN2, and 15/16 (94%) CIN3 lesions were p16 positive (defined as diffuse block staining in at least one third of the epithelial thickness). One CIN3 was negative for both p16 and STMN. Ki67 and p27 staining was variable in squamous lesions. These results demonstrate that STMN is overexpressed in virtually all cervical carcinomas and CIN3 lesions. In contrast to p16, which often stains LSIL and a small subset of reactive biopsies, STMN has greater specificity for CIN3 and has the potential to distinguish these latter lesions from the majority of low-grade precursors and negative/reactive cervical biopsies. STMN overexpression appears independent of proliferation, maturation, and human papilloma virus cytopathic effect and may be useful diagnostically in identifying HSIL. Further studies correlating STMN staining with lesion persistence or morphologic progression, in the context of CIN grade, are warranted.

    View details for DOI 10.1097/PAS.0b013e3182753f5a

    View details for PubMedID 23211296

  • Vascular Lesions of the Breast. Surgical pathology clinics Howitt, B., Nascimento, A. F. 2012; 5 (3): 645-59


    Vascular lesions represent a minority of tumors originating in the breast. The most common entities are benign and include hemangiomas and angiolipomas. Malignant vascular lesions (angiosarcomas) are rare and may be primary or secondary to radiation. Also appreciated in association to radiotherapy is the development of cutaneous atypical vascular lesion affecting the skin of the breast. The relationship of the latter to radiation-associated angiosarcoma is controversial and remains to be elucidated. This article reviews the most likely encountered vascular lesions in the breast, with emphasis on key pathologic diagnostic features and potential diagnostic pitfalls.

    View details for DOI 10.1016/j.path.2012.06.002

    View details for PubMedID 26838283