2019 Volume 35 Issue 2 Pages 143-147
Neurocutaneous melanosis (NCM) is a rare congenital disease consisting of development of congenital giant melanocytic nevi and CNS melanocytosis. We present two neonates who had giant congenital nevi and multiple smaller satellite melanocytic nevi on the scalp and extremities, with brain MRI findings characteristic of NCM. In both neonates, MRI demonstrated multiple brain parenchymal foci of T1 hyperintensity and T2 hypointensity, signal characteristics of melanin with the T1, and T2 shortening effects. These foci were seen in the amygdalae, brain stem, and cerebellum. In one neonate, dilatation of the ventricular system and subarachnoid space was identified, representing communicating hydrocephalus. These intracranial findings are characteristic of NCM. No obvious leptomeningeal contrast enhancement was demonstrated. MRI can provide useful information for the diagnosis and follow up of NCM.