Segmental neurofibromatosis in association with nevus sebaceus of Jadassohn.

We describe an unusual case involving the simultaneous occurrence of segmental neurofibromatosis (Type V NF) in a patient with a large nevus sebaceus of Jadassohn in the same physical distribution. Causative mechanisms of development of these 2 genetic disorders have not been definitively linked. Factors producing these diseases probably involve similar tissues at the same point in development because both have been reported in association with central nervous system anomalies and have been classified among the neurocutaneous syndromes. This is a case of a nevus sebaceus occurring in association with and in the same physical distribution as segmental NF. These disorders most likely represent a spectrum of disease within the phakomatoses.