Primary leptomeningeal melanocytosis presenting as chronic meningitis.

We report a patient with primary leptomeningeal melanocytosis presenting as chronic meningitis. A previously healthy 27-year-old man presented with 2 months of severe headaches and photophobia. A lumbar puncture was notable for a highly elevated cerebrospinal fluid (CSF) protein level without pleocytosis. Imaging at the time of admission suggested only meningitis without the presence of parenchymal lesions. On the basis of the CSF findings, early meningeal biopsy was performed, leading to the diagnosis of a meningeal melanocytic neoplasm. Early meningeal biopsy should be considered in patients with meningitis when the CSF profile suggests the possibility of a central nervous system neoplasm.