Epidermal nevi and localized cranial defects.

We report on a girl with a congenital pigmented hairy nevus of the scalp, epidermal nevi of the right temple, and localized cranial defects. We have not found other reported cases of giant pigmented hairy nevus of the scalp occurring with absence of underlying cranial bone. We speculate that the localized cranial defects are undergrowth anomalies representative of a paracrinopathy from the overlying nevus or simultaneous bone/skin dysplasia, the former having been resorbed. In the absence of a familial history of epidermal nevi and/or seizures, our patient represents a sporadic case, perhaps a somatic mutation.