Volume 21 Number 4 April 2015 Photo vignette Squamous cell carcinoma in the setting of chronic hidradenitis suppurativa; report of a patient and update of the literature. Zachary G Peña MD 1 , Raja K. Sivamani MD 2 , Thomas H. Konia MD 2 , Daniel B. Eisen MD 2 Dermatology Online Journal 21 (4): 12 1 Department of Dermatology, Oregon Health and Science University, Portland, Oregon, USA 2 Department of Dermatology, University of California Davis Medical Center, Sacramento, California, USA Correspondence: Daniel B. Eisen, MD Dept. of Dermatology University of California Davis Medical Center 3301 C St, #1400 Sacramento, CA 95816 dbeisen@ucdavis.edu (916) 734-6111 Abstract Squamous cell carcinoma (SCC) developing in chronic hidradenitis suppurativa (HS) is rare, but failing to recognize the condition may have significant consequences. Dermatologists must be aware of the potential for malignant transformation and should have a low threshold for biopsy when clinical presentation is atypical. Herein we describe a 64-year-old woman with metastatic vulvar SCC that developed within an area of chronic HS. Like SCC associated with other chronic inflammatory disorders (Marjolin’s ulcers), mortality is significant. Past reviews have reported death rates above 40% and our most recent update continues to support poor prognoses for these patients. Keywords: Hidradenitis suppurativa; Squamous cell carcinoma Introduction Hidradenitis suppurativa is a relatively common chronic inflammatory condition affecting the apocrine gland bearing skin of otherwise healthy individuals. Follicular occlusion, chronic relapsing inflammation, mucopurulent discharge, and progressive scarring characterize the disease. Rarely, malignant transformation may occur, with SCC being most commonly described. We add another report herein and update the literature on this topic to date. Case synopsis A 64-year-old woman presented with large, swollen, red, painful nodules in the groin. She reported intermittent symptoms beginning in her twenties, but noted these always resolved without treatment. Over the past year she developed persistent nodules in the right groin, treated initially with antibiotic cream and testosterone, followed by 10 days of oral sulfamethoxazole- trimethoprim, which had no clinical effect. A fluctuant right labial mass developed, which was subsequently incised and the area cultured. Results from the bacterial culture identified normal skin flora. She subsequently completed 14 days of clindamycin