We report a case of primary diffuse meningeal melanomatosis, a rare variant of primary malignant melanoma of the CNS, in a 25-year-old woman. The disease was clinically manifested with obstructive hydrocephalus and severe polyneuritis of cranial and spinal nerves. The results of the CSF cytology and biopsy of the meninges were negative. There was a steady progression of the disease despite the success of the ventriculoatrial shunt. The disease was diagnosed only at autopsy
