Extensive cerebriform nevus sebaceus: an unusual presentation.

Nevus sebaceus is an epidermal nevi composed of sebaceous glands, which usually presents as single yellowish plaque over the head and neck. A rare morphological variant, namely cerebriform nevus sebaceus was first reported in 1998. As with other nevi, the occurrence of nevus sebaceous is related to genetic mosaicism and the shape and distribution of the nevus is determined by the stage at which mosaicism has arisen. We report a patient with cerebriform nevus sebaceus having an unusually widespread distribution over the head, face, and trunk, but without any other organ system involvement.