A case of squamous cell carcinoma arising in an epidermal cyst on the left buttock

Abstract

We report a case of squamous cell carcinoma arising in an epidermal cyst. The patient was a 78-year-old man who had a ten-year history of a mass on his left buttock. The lesion had gradually enlarged during the previous years. An excisional biopsy was performed. Histpathologically, there was a cystic lesion composed of benign squamous epithelia with a transition to squamous cell carcinoma. The patient is alive without local recurrence or distant metastasis at six months postoperatively. Malignant transformation of an epidermal cyst is uncommon.[Skin Cancer (Japan) 2010 ; 25 : 358-362]