Sebaceous carcinoma arising from Bowen's disease of the vulva.

Sebaceous neoplasms are a marker for malignancy in the Muir-Torre syndrome. Bowen's disease has also been regarded by some as a cutaneous marker for various internal malignancies. An 89-year-old woman was noted to have a sebaceous carcinoma arising within a focus of vulvar Bowen's disease. To our knowledge, this is the first known instance of such an occurrence. The finding of a sebaceous carcinoma in association with an atypical proliferation of keratinocytic, rather than basaloid, origin is unusual and is not accounted for in most classifications of sebaceous malignancy. This observation further supports the pluripotential nature of the cell line giving rise to both Bowen's disease and sebaceous neoplasms.