Spinal meningeal melanocytoma

Primary melanotic meningeal neoplasms are extremely rare lesions and benign forms are even rarer though with better prognosis than the malignant ones. We describe a 40-year-old male with a history of gradually progressive weakness of both lower limbs with normal bowel, bladder control, and an intradural mass measuring 1.5×1.0 cm on radiologic investigations. The lesion was surgically excised. Histopathologic examination revealed heavily melanin-pigmented cells, nuclei with reticulogranular chromatin and small nucleoli, moderate amount of eosinophillic cytoplasm with indistinct cell boundaries, and symplasmic appearance. A probable diagnosis of meningeal melanocytoma was made. The diagnosis was confirmed on immunohistochemical analysis which revealed strongly positive expression of HMB-45 in the tumor cells. Vimentin and S-100 were also diffusely positive while neuron specific enolase showed focal and patchy positivity; however, epithelial membrane antigen was distinctly negative.