Squamous cell carcinoma in a linear epidermal nevus.

An 81-year-old African American female presented with a 3-year history of a slow, persistently enlarging mass on the medial aspect of her left thigh. Her past history was remarkable for a congenital linear epidermal naevus that was present on the inner aspect of her left thigh. A biopsy of the mass was performed and histology results confirmed the diagnosis of a well differentiated squamous cell carcinoma. Such an occurrence is extremely rare and less than 10 cases have been reported in the literature.