Postauricular cerebriform sebaceous nevus: case report and literature review.

Epidermal nevi are abnormal collections of cells derived from the embryonic epidermis. They are believed to represent cutaneous genetic mosaicism, with the histopathologic appearance related to mutations in genes involved in epidermal growth and differentiation. The clinical phenotype and potential inheritance are also related to these mutations and the time during embryogenesis when a mutation occurs. Since mutation timing in development is variable and the alleles are numerous, nevi have wide clinical variation. The lesions can be solitary, occur diffusely, or arise in association with other organ system abnormalities. Sebaceous nevus is a common subtype of epidermal nevi in which sebaceous gland-like structures predominate microscopically. Most lesions are alopecic, flat or slightly raised, and appear on the face and scalp. We review the presentation and treatment of a patient with an unusual appearing postauricular sebaceous nevus that was raised in a cerebriform appearing fashion, and discuss the related literature.