Squamous Cell Carcinoma in Perineal, Perianal, and Gluteal Hidradenitis Suppurativa: Experience in 12 Patients.

BACKGROUND Few reports describe squamous cell carcinoma (SCC) arising in hidradenitis suppurativa (HS). OBJECTIVE The 2 objectives were (1) to describe the clinical characteristics, pathologic findings, and postoperative outcomes of SCC in HS and (2) to assess whether human papillomavirus (HPV) is involved in the pathogenesis. MATERIALS AND METHODS Cases of SCC in HS were identified through institutional medical records (1976-2013) and the Rochester Epidemiology Project. Tumor specimens were assessed for HPV DNA/RNA with in situ hybridization. RESULTS Twelve patients were identified (11 Caucasians and 9 men). All SCCs involved gluteal, perianal, or perineal skin; 1 patient had, in addition, involvement of the vagina. Surgical excision was performed on all 12 patients, 4 of whom had a colostomy. Mean duration of HS before SCC development was 28.5 years (range, 1553 years). Mean follow-up was 4.3 years after surgical excision. Seven of 12 patients followed had postoperative SCC recurrence. Squamous cell carcinoma caused death despite wide surgical excision in these 7 patients. Of the remaining 5 patients, 4 are unknown and 1 who did not recur had an in situ SCC (Bowen disease carcinoma). Squamous cell carcinoma was not associated with high-risk or low-risk HPV. CONCLUSION Invasive SCC arising in HS carries a high risk of death.