Background:
Primary melanocytic tumors of the central nervous system (CNS) represent only 1% of all melanomas. We report two rare cases of primary diffuse leptomeningeal melanomatosis (PDLM; case 1) and primary melanoma of the thoraco-lumbar spine (case 2).
Case description:
In case 1, multiple cerebrospinal fluid (CSF) studies and a brain biopsy were non-diagnostic, with a biopsy of the cauda equina eventually demonstrating malignant melanomatosis. Diagnosis of primary spinal cord melanoma was more straightforward in case 2 with imaging and biopsy.
Conclusion:
PDLM and primary intramedullary spinal melanoma are rare variants of primary CNS melanoma. This report contrasts the diagnostic challenges between the two entities and alerts the neurosurgeon into considering the diagnosis with appropriate clinical presentation.