Basal cell carcinoma within nevus sebaceous of the trunk.

We report the first case of an 82-year-old woman with five basal cell carcinomas within a large nevus sebaceous of the trunk. Nevus sebaceous of Jadassohn is a congenital cutaneous hamartoma affecting 0.3% of newborns. Clinical diagnosis is based on its distinctive hairless, orange-brown appearance. Up to 51% of nevus sebaceous may exhibit secondary neoplasia, and basal cell carcinoma is thought to occur in approximately 1% of lesions. Our patient presented with an asymptomatic, pigmented verrucous plaque on the upper right back that had been present since birth. Histopathology of concerning papules within the nevus sebaceous were consistent with five basal cell carcinomas and two follicular adnexal neoplasms. The patient was treated with local excisions, topical imiquimod, and close monitoring.