Squamous Cell Carcinoma Arising on a Background of Epidermal Inclusion Cyst Over the Gluteal Region – A Case Report

Background: Methods: Epidermal inclusion cysts are the most common cutaneous cysts, but malignant transformation in them is extremely rare. We present a case of a 63-year-old female with a swelling in the right gluteal region with associated discharge that was resected based on the clinical impression and cytology of an epidermal inclusion cyst. Histopathologic exam showed atypical cells with enlarged nuclei and prominent nucleoli with brisk mitotic activity, and on IHC, these cells were positive for PanCK and P40 and negative for Sox10, conrming the diagnosis of Poorly Differentiated Squamous Cell Carcinoma. There are 56 reported cases of SCC arising on a background Conclusion: of epidermal inclusion cysts in literature. Although epidermal inclusion cysts are usually benign, excision is recommended for atypical cysts with high suspicion for malignancy. They should be excised intact and should undergo histopathological examination to rule out incipient malignancy.