[Neurocutaneous melanosis]

Neurocutaneous melanosis is an infrequent condition characterized by the presence of numerous gigantic cutaneous naevi and melanocytic infiltration of the central nervous system and/or the leptomeningeal layers. Different clinical features may be seen: endocranial hypertension due to hydrocephalus, cranial nerve paralysis, myelopathy, convulsive seizures, etc. The prognosis is considered to be malignant. Only positive CNS histological findings confirm the diagnosis.

We present the case of a man with cutaneous lesions compatible with the diagnosis of neurocutaneous melanosis since birth, with benign self-limiting epilepsy in early childhood. Cerebral CT and MR scans were normal until the age of 17, when hipper-signal lesions appeared on MR, infiltrating the leptomeninges of the deep temporal pole and anterior aspect of the cerebral peduncles, which suggested the presence of melanocytes in the CNS.

There are cases of neurocutaneous melanosis with a good medium-term prognosis and benign manifestations until infiltration of the CNS occurs. Then they start to show the classical behavior of cases with a malignant prognosis. MR should be included as part of the diagnostic criteria for neurocutaneous melanosis. MR should be done periodically in patients with cutaneous lesions suggestive of this condition.