Congenital melanocytosis with myelomeningocele and hydrocephalus.

We report an infant who had diffuse blue hyperpigmentation at birth, which rapidly progressed to gray, over the back, buttocks, and posterior aspect of the legs, and an associated congenital anomaly. The entire thickness of the dermis contained numerous very prominent melanocytic cells which, especially in the superficial dermis, were markedly dendritic, rather than merely fusiform. An epidermal melanocyte proliferation was also present. Histologically, the lesion thus differed markedly from a mongolian spot. We believe that diffuse hyperpigmentation in the neonate should call attention to the possibility of an associated neuroectodermal malformation.