Bio


Dr. Kelsey Hirotsu is a Clinical Assistant Professor of Dermatology at Stanford University School of Medicine. She completed her fellowship in Mohs Micrographic Surgery & Dermatologic Oncology at the University of California San Diego. During fellowship she received additional training in cosmetic dermatology and laser procedures. She completed her dermatology residency at Stanford after graduating from Stanford University School of Medicine with a scholarly concentration in bioengineering. Dr. Hirotsu earned her Bachelor of Science degree in Chemical & Biomolecular Engineering at Johns Hopkins University.

Dr. Hirotsu has presented at national and international dermatology conferences. She is a regularly invited reviewer for peer-reviewed journals and has authored numerous publications in top dermatology journals.

Clinical Focus


  • Dermatology
  • Dermatologic Surgery
  • Mohs Micrographic Surgery

Academic Appointments


Professional Education


  • Internship: Scripps Mercy Hospital San Diego (2018) CA
  • Fellowship: UCSD Dermatology Fellowships (2022) CA
  • Board Certification: American Board of Dermatology, Dermatology (2021)
  • Residency: Stanford University Dermatology Residency (2021) CA
  • Medical Education: Stanford University School of Medicine (2017) CA

All Publications


  • Acanthosis nigricans in the setting of severe pulmonary disease exacerbated by COVID-19 infection. JAAD case reports Hirotsu, K. E., Chiang, A., Bahrani, E., Cloutier, J. M., Rieger, K. E., Kwong, B. Y., Aleshin, M. 2022

    View details for DOI 10.1016/j.jdcr.2022.04.017

    View details for PubMedID 35529073

  • Histologic subtype of cutaneous immune-related adverse events predicts overall survival in patients receiving immune checkpoint inhibitors. Journal of the American Academy of Dermatology Hirotsu, K. E., Scott, M. K., Marquez, C., Tran, A. T., Rieger, K. E., Novoa, R. A., Robinson, W. H., Kwong, B. Y., Zaba, L. C. 2021

    View details for DOI 10.1016/j.jaad.2021.11.050

    View details for PubMedID 34875301

  • Complete remission from intralesional talimogene laherparepvec for regionally advanced Merkel cell carcinoma in an immunocompromised solid organ transplant patient. JAAD case reports Hirotsu, K. E., Hua, V., Tran, A. T., Morris, L., Reddy, S. A., Kwong, B. Y., Zaba, L. C. 2021; 13: 144-146

    View details for DOI 10.1016/j.jdcr.2021.05.005

    View details for PubMedID 34195326

  • Clinical Characterization of Mogamulizumab-Associated Rash During Treatment of Mycosis Fungoides or Sezary Syndrome. JAMA dermatology Hirotsu, K. E., Neal, T. M., Khodadoust, M. S., Wang, J. Y., Rieger, K. E., Strelo, J., Hong, E., Kim, Y. H., Kwong, B. Y. 2021

    Abstract

    Importance: Mogamulizumab is a monoclonal antibody against CCR4 approved for treatment for mycosis fungoides (MF) and Sezary syndrome (SS). Mogamulizumab-associated rash (MAR) is difficult to differentiate from cutaneous MF or SS, which can lead to unnecessary discontinuation of drug use because of concern for severe drug reaction or incorrect presumption of disease relapse or progression in the skin.Objective: To examine the most common clinical presentations of MAR in patients with MF or SS and the diagnostic and management challenges.Design, Setting, and Participants: This retrospective case series assessed patients from a multidisciplinary cutaneous lymphoma clinic and supportive oncodermatology clinic at a major academic referral center who had a diagnosis of MF or SS and received mogamulizumab from January 1, 2013, to January 1, 2020. Treatment was followed by new or worsening rash with skin biopsy results compatible with drug eruption determined by clinicopathologic correlation and molecular testing to exclude active malignant disease.Exposures: At least 1 dose of mogamulizumab.Main Outcomes and Measures: Mogamulizumab-associated rash was characterized by clinical features, including time to onset, clinical presentation, histopathologic features, and management approach.Results: The study included 19 patients with MF or SS who developed MAR (median age, 65 years; age range, 38-82 years; 10 [52.6%] male). Median time to MAR onset was 119 days (range, 56 days to 3.8 years). Patients with MAR exhibited 4 predominant clinical presentations: (1) folliculotropic MF-like scalp plaques with alopecia, (2) papules and/or plaques, (3) photoaccentuated dermatitis, and (4) morbilliform or erythrodermic dermatitis. The most common anatomical region involved was the head and neck, including the scalp. Histopathologic findings were variable and did not correspond to primary clinical morphologic findings. Immunohistochemistry and T-cell clonality ancillary testing were helpful to distinguish MAR from disease. Most patients with MAR (14 of 19) discontinued mogamulizumab treatment; however, no life-threatening severe cutaneous adverse drug reactions occurred, and the decision for drug therapy cessation was usually multifactorial. Four patients were treated again with mogamulizumab with no life-threatening drug-related events. Approaches to management of MAR include topical corticosteroids, systemic corticosteroids, and/or methotrexate.Conclusions and Relevance: This case series found that mogamulizumab-associated rash had a heterogeneous clinical presentation with variable and delayed onset in patients with MF or SS. Mogamulizumab-associated rash exhibited a predilection for the head and neck and was difficult to clinically distinguish from relapse or progression of disease. Recognition of the most common clinical presentations can help prevent unnecessary discontinuation of mogamulizumab treatment. The presence of MAR does not necessitate permanent discontinuation of or avoidance of retreatment with mogamulizumab.

    View details for DOI 10.1001/jamadermatol.2021.0877

    View details for PubMedID 33881447

  • An ulcerated violaceous nodule on the thigh. JAAD case reports Hirotsu, K. E., Kumar, A. M., Rieger, K. E., Chen, J. K. 2021; 9: 61–63

    View details for DOI 10.1016/j.jdcr.2021.01.011

    View details for PubMedID 33665278

  • Histopathologic Characterization of Mogamulizumab-associated Rash. The American journal of surgical pathology Wang, J. Y., Hirotsu, K. E., Neal, T. M., Raghavan, S. S., Kwong, B. Y., Khodadoust, M. S., Brown, R. A., Novoa, R. A., Kim, Y. H., Rieger, K. E. 2020

    Abstract

    Rash is one of the most common adverse events observed with mogamulizumab, an anti-C-C chemokine receptor 4 monoclonal antibody approved for previously treated mycosis fungoides (MF) and Sezary syndrome (SS). Given the nonspecific clinical presentations of this rash, histopathologic distinction from MF/SS is critical for informing clinical management. We performed a comprehensive characterization of the histopathologic findings in mogamulizumab-associated rash (MAR) with the integration of high-throughput sequencing of T-cell receptor (TCR) genes. Fifty-two biopsy specimens from 19 patients were evaluated retrospectively. Three major histologic reaction patterns were identified: spongiotic/psoriasiform dermatitis (33/52), interface dermatitis (11/52), and granulomatous dermatitis (8/52). Almost half of the specimens (21/52) showed at least 2 of these reaction patterns concurrently. Dermal eosinophils were not a consistent feature, being present in only half (27/52) of specimens and prominent in only 3. Features mimicking MF/SS, including lymphocyte exocytosis, lamellar fibroplasia, and adnexal involvement, were commonly seen but tended to be focal and mild. In 38/43 specimens with available immunohistochemistry, intraepidermal lymphocytes demonstrated a CD4:CD8 ratio ≤1 : 1. Low background levels of the patient's previously identified MF/SS-associated TCR sequence(s) were demonstrated in 20/46 specimens analyzed by high-throughput sequencing of TCR. We conclude that MAR may demonstrate diverse histologic features. Findings that may distinguish MAR from MF/SS include the inverted or normalized CD4:CD8 ratio within intraepidermal lymphocytes and demonstration of absent or nondominant levels of disease-associated TCR sequences. Correlation with the clinical findings and immunohistochemical and molecular characterization of the patient's MF/SS before mogamulizumab, when possible, may facilitate recognition of MAR.

    View details for DOI 10.1097/PAS.0000000000001587

    View details for PubMedID 32976123

  • Clinicopathologic characterization of enfortumab vedotin-associated cutaneous toxicity in patients with urothelial carcinoma. Journal of the American Academy of Dermatology Hirotsu, K. E., Rana, J. n., Wang, J. Y., Raghavan, S. S., Rieger, K. E., Srinivas, S. n., Fan, A. C., Kwong, B. Y., Novoa, R. A., Zaba, L. n. 2020

    View details for DOI 10.1016/j.jaad.2020.11.067

    View details for PubMedID 33301805

  • Treatment of Hypertrophic Granulation Tissue: A Literature Review. Dermatologic surgery : official publication for American Society for Dermatologic Surgery [et al.] Hirotsu, K., Kannan, S., Brian Jiang, S. I. 2019

    Abstract

    BACKGROUND: Hypertrophic granulation tissue (HGT) is an uncommon but a frustrating complication of wound healing. Given its low prevalence and often refractory nature, many treatment options have been explored.OBJECTIVE: No comprehensive review exists on HGT management in dermatology literature; thus, the authors hope to compile a review of available treatments.MATERIALS AND METHODS: An exhaustive key word search of 3 databases was performed for treatment of HGT. Results from these reports were summarized in this review.RESULTS: Methods of treatment included silver nitrate, topical steroids (n = 11), intralesional steroids (n = 55), steroid tape (n = 25), surgical removal, polyurethane foam dressing (n = 32), and pulsed-dye laser (n = 13).CONCLUSION: With all treatment methods, the cases and studies reported varying degrees of successful treatment with HGT reduction. Given the lack of published literature, it remains unknown whether the initial injury preceding HGT formation determines treatment modality success. For HGT refractory to silver nitrate, choice of treatment depends on accessibility, ease of use, cost, and location of the wound. Intralesional and topical steroids should both be considered. Polyurethane foam can be considered an adjunct treatment. If resources allow, laser treatment should also be considered.

    View details for DOI 10.1097/DSS.0000000000002059

    View details for PubMedID 31403535

  • Association of Antibiotic Resistance With Antibiotic Use for Epidermal Growth Factor Receptor Inhibitor-Related Papulopustular Eruption JAMA DERMATOLOGY Hirotsu, K., Dang, T. M., Li, S., Neal, J. W., Pugliese, S., Subramanian, A., Kwong, B. Y. 2019; 155 (7): 848–50
  • Association of Antibiotic Resistance With Antibiotic Use for Epidermal Growth Factor Receptor Inhibitor-Related Papulopustular Eruption. JAMA dermatology Hirotsu, K. n., Dang, T. M., Li, S. n., Neal, J. W., Pugliese, S. n., Subramanian, A. n., Kwong, B. Y. 2019

    View details for PubMedID 31017625

  • Cardiotoxicity associated with immune checkpoint inhibitors in cutaneous oncology. Journal of the American Academy of Dermatology Tabata, M. M., Choi, S. n., Hirotsu, K. n., Kwong, B. n., Soleymani, T. n. 2019

    View details for DOI 10.1016/j.jaad.2019.08.033

    View details for PubMedID 31437546

  • Geometric Deformations of the Thoracic Aorta and Supra-Aortic Arch Branch Vessels Following Thoracic Endovascular Aortic Repair VASCULAR AND ENDOVASCULAR SURGERY Ullery, B. W., Suh, G., Hirotsu, K., Zhu, D., Lee, J. T., Dake, M. D., Fleischmann, D., Cheng, C. P. 2018; 52 (3): 173–80

    Abstract

    To utilize 3-D modeling techniques to better characterize geometric deformations of the supra-aortic arch branch vessels and descending thoracic aorta after thoracic endovascular aortic repair.Eighteen patients underwent endovascular repair of either type B aortic dissection (n = 10) or thoracic aortic aneurysm (n = 8). Computed tomography angiography was obtained pre- and postprocedure, and 3-D geometric models of the aorta and supra-aortic branch vessels were constructed. Branch angle of the supra-aortic branch vessels and curvature metrics of the ascending aorta, aortic arch, and stented thoracic aortic lumen were calculated both at pre- and postintervention.The left common carotid artery branch angle was lower than the left subclavian artery angles preintervention ( P < .005) and lower than both the left subclavian and brachiocephalic branch angles postintervention ( P < .05). From pre- to postoperative, no significant change in branch angle was found in any of the great vessels. Maximum curvature change of the stented lumen from pre- to postprocedure was greater than those of the ascending aorta and aortic arch ( P < .05).Thoracic endovascular aortic repair results in relative straightening of the stented aortic region and also accentuates the native curvature of the ascending aorta when the endograft has a more proximal landing zone. Supra-aortic branch vessel angulation remains relatively static when proximal landing zones are distal to the left common carotid artery.

    View details for PubMedID 29400263

  • Promoting sunscreen use and sun-protective practices in NCAA athletes: Impact of SUNSPORT educational intervention for student-athletes, athletic trainers, and coaches JOURNAL OF THE AMERICAN ACADEMY OF DERMATOLOGY Ally, M. S., Swetter, S. M., Hirotsu, K. E., Gordon, J., Kim, D., Wysong, A., Donnelly, L., Li, S., Nord, K. M. 2018; 78 (2): 289-+

    Abstract

    Student-athletes (SAs) have an increased skin cancer risk on account of significant ultraviolet exposure; however, their sun-protective practices are suboptimal. A novel program, Stanford University Network for Sun Protection, Outreach, Research, and Teamwork (SUNSPORT), was designed to target SAs, coaches, and athletic trainers (ATs).To measure the impact of educational intervention on sun protection beliefs and practices of SAs.A survey of sun protection beliefs and practices was administered to National Collegiate Athletic Association athletes before and after intervention. SUNSPORT dermatologists educated SAs, coaches, and ATs regarding skin cancer risk and prevention methods. The main outcome was frequency of sunscreen use by SAs before versus after intervention.A total of 846 National Collegiate Athletic Association athletes were surveyed between September 23, 2012, and September 20, 2015. After intervention, significant increases were observed in sunscreen use 4 or more days per week by SAs (from 26% to 39% [P = .02]), SAs spoken to by their coach about sun safety (from 26% to 57% [P = .0001]), and SA recognition of higher skin cancer risk (from 54% to 67% [P = .04]).Intervention in only 1 West Coast university and no paired data.Following the SUNSPORT intervention, SAs were significantly more likely to use sunscreen, especially if encouraged by their coach. This study emphasizes that education directed to SAs, ATs, and coaches can improve sun-protective practices in SAs.

    View details for PubMedID 28993006

  • Changes in Geometry and Cardiac Deformation of the Thoracic Aorta after Thoracic Endovascular Aortic Repair Hirotsu, K., Suh, G., Lee, J. T., Dake, M. D., Fleischmann, D., Cheng, C. P. ELSEVIER SCIENCE INC. 2018: 83–89
  • Changes in Geometry and Cardiac Deformation of the Thoracic Aorta after Thoracic Endovascular Aortic Repair. Annals of vascular surgery Hirotsu, K., Suh, G., Lee, J. T., Dake, M. D., Fleischmann, D., Cheng, C. P. 2017

    Abstract

    BACKGROUND: Thoracic endovascular aortic repair (TEVAR) has dramatically expanded treatment options for patients with thoracic aortic pathology. The interaction between endografts and the dynamic anatomy of the thoracic aorta is not well characterized for repetitive physiologic stressors and subsequent issues related to long-term durability. Through three-dimensional (3D) modeling we sought to quantify cardiac-induced aortic deformation before and after TEVAR to assess the impact of endografts on dynamic aortic anatomy.METHODS: Eight patients with acute (n=4) or chronic (n=3) type B dissections, or chronic arch aneurysm (n=1), underwent TEVAR with a single (n=5) or multiple (n=3) Gore C-TAG(s). Cardiac-resolved thoracic CT images were acquired pre- and post-TEVAR. 3D models of thoracic aorta and branch vessels were constructed in systole and diastole. Axial length, mean, and peak curvature of the ascending aorta, arch, and stented lumens were computed from the aortic lumen centerline, delineated with branch vessel landmarks. Cardiac-induced deformation was computed from mid-diastole to end-systole.RESULTS: Pre-TEVAR, there were no significant cardiac-induced changes for aortic axial length or mean curvature. Post-TEVAR, the ascending aorta increased in axial length (2.7±3.1%, P<0.05) and decreased in mean curvature (0.38±0.05 0.36±0.05cm-1, P<0.05) from diastole to systole. From pre- to post-TEVAR, axial length change increased in the ascending aorta (P<0.02), mean curvature decreased in the arch and stented aorta (P<0.03), and peak curvature decreased in the stented aorta (P<0.05).CONCLUSIONS: TEVAR for a range of indications not only causes direct geometric changes to the stented aorta but also results in dynamic changes to the ascending and stented aorta. In our cohort, endograft placement straightens the stented aorta and mutes cardiac-induced bending due to longitudinal stiffness. This is compensated by greater length and curvature changes from diastole to systole in the ascending aorta, relative to pre-TEVAR.

    View details for PubMedID 28887263

  • Localized bullous pemphigoid in a melanoma patient with dual exposure to PD-1 checkpoint inhibition and radiation therapy. JAAD case reports Hirotsu, K. n., Chiou, A. S., Chiang, A. n., Kim, J. n., Kwong, B. Y., Pugliese, S. n. 2017; 3 (5): 404–6

    View details for PubMedID 28884139

  • Volumetric analysis demonstrates that true and false lumen remodeling persists for 12 months after thoracic endovascular aortic repair JOURNAL OF VASCULAR SURGERY CASES AND INNOVATIVE TECHNIQUES Suh, G., Hirotsu, K., Beygui, R. E., Dake, M. D., Fleischmann, D., Cheng, C. P. 2016; 2 (3): 101–4
  • Geometric analysis of thoracic aorta and arch branches before and after TEVAR Suh, G., Hirotsu, K., Zhu, Y. D., Lee, J., Dake, M., Fleischmann, D., Cheng, C. ELSEVIER SCIENCE INC. 2015: B129