Abstract
We reported a case of squamous cell carcinoma arising in an epidermal cyst. The patient was an 87-year-old woman who had a fifty year history of a mass on her left buttock. The lesion had gradually enlarged during the previous year. An excisional biopsy was done. Histpathologically, there was a cystic lesion composed of benign squamous epithelium with a transition to squamous cell carcinoma. Malignant degeneration of an epidermal cyst is uncommon.
