NEUROCUTANEOUS MELANOSIS

This is a report of a 28‐day‐old male infant who had concommitant pigmented melanocytic nevi and meningeal melanosis. Pigment cells of the two lesions were observed by electron microscopy and compared with previous reports of nevus cell nevus, meningeal melanosis, meningeal melanocytoma and leptomeningeal malignant melanoma. Based on our findings, we have reached the following three conclusions: (1) Pigment cells in the nevus and meningeal melanosis in our case were similar in their cellular structures and their relationship to blood vessels and consistent with a neural crest origin for pigment cells; (2) Ultrastructural characteristics of the meningeal melanosis in our case were similar to those of the meningeal melanocytoma; (3) Pigment cells in meningeal melanosis have tumorous potential and may tend to cause malignant changes.