OBJECTIVE: Neurocutaneus melanosis is a phacomatosis characterized by the presence on the body of multiple nevi with tendency to change into aggressive melanocytic forms and by the presence of melanin deposits involving the central nervous system. Prognosis is overall considered to be poor. MATERIAL AND METHODS: Two cases observed at the Pediatric Neurosurgery Unit of the Catholic University Medical School in Rome are described. Both of them had cutaneous stigmata and cerebral MR evidence of intracranial melanin deposits. These two children showed a very different clinical course. RESULT: The present study enlighten the differences among the two cases and review the literature on the subject, with the attempt to understand which are clinical and disease related factors that might influence the prognosis. CONCLUSION: Beside malignant features of cutaneous melanotic lesions, the presence of hydrocephalus at diagnosis and the early appearance of clinical symptoms, when appearing contemporarily, are predicting the rapid progression of the disease and a worse prognosis.