Hidradenitis suppurativa complicated by squamous cell carcinoma.

Hidradenitis suppurativa (HS) is a chronic inflammatory condition affecting the apocrine glands of the axilla, groin, and perianal region. Although it is a common condition, it is rarely associated with squamous cell carcinoma (SCC). There have been only 41 reports of this uncommon complication of HS in the literature. This study includes two uncommon presentations of HS associated with SCC along with a literature review. The first patient developed diffuse abdominal carcinomatosis from SCC in the anogenital region arising from HS. This is a rare event in patients with perianal SCC, with only one case previously described in the literature. The second patient developed malignant hypercalcemia, an uncommon complication of cutaneous SCC. The current report represents the largest review of the literature of patients with SCC secondary to longstanding HS. A recurrence rate of 48 per cent was observed after "curative" resection. Approximately half of the patients succumbed to their disease, and the grade of carcinoma was the only predictor of mortality. These two new cases underline the importance of close follow-up and aggressive management of patients with HS. Although the development of carcinoma is an uncommon event in HS, the consequences can be devastating with mortality approaching 50 per cent.