Primary spinal cord melanoma in thoracic spine with leptomeningeal dissemination and presenting hydrocephalus.

Primary spinal cord melanoma is a rare central nervous system malignant tumor. Usually it resembles an intradural extramedullary (IDEM) nerve sheath tumor or melanoma. We experienced a patient with upper thoracic primary IDEM spinal cord melanoma who was diagnosed to be with hydrocephalus and without intracranial lesions. Initial symptoms of the patient were related to the hydrocephalus and the primary spinal cord melanoma was diagnosed eight months later. At the first operation, complete resection was impossible and the patient refused additional radiotherapy or chemotherapy. At 22 months after surgery, the patient revisited our institution with recurrent both leg weakness. Leptomeningeal dissemination was present in the whole spinal cord and only partial resection of tumor was performed. The symptoms slightly improved after surgery. Primary spinal cord melanoma is extremely rare but complete resection and additional radiotherapy or chemotherapy can prolong the disease free interval. Hydrocephalus or signs of increased intracranial pressure may be the diagnostic clue of spinal cord malignancy and progression.