Intermediate grade meningeal melanocytoma of cervical spine

Meningeal melanocytoma is a rare, benign melanotic tumor of the leptomeninges, which occurs anywhere in the cranial or spinal regions but most commonly in supratentorial and thoracic spine regions. The literature on this entity consists of case reports; therefore, there is no agreement on the most effective therapy of this tumor, although total excision seems to be the best therapeutic option.

We report a 17-year-old girl with intermediate grade meningeal melanocytoma involving the C6 nerve root with spinal cord compression resulted in progressive tetraparesis. Clinical and radiological examinations suggested the possibility of an intradural extramedullary solid mass. The tumor was removed subtotally through cervical laminotomy followed by rapid improvement of most neurological deficits. This tumor was unusual because of its very hyperintense homogenous signal on T1-weighted images, invasion of the arachnoid membrane, and extension into the neural foramina. Black dots on the surface of the cord were thought to represent an organized blood clot until the frozen section suggested a melanocytic tumor.

We discuss the distinction of meningeal melanocytoma from other melanocytic tumors of the leptomeninges.

Melanocytic tumors should be considered in the differential diagnosis when a hyperintense lesion of the leptomeninges is identified on T1-weighted images or a very dark mass similar to charcoal or organized hematoma is found in the surgical field. The best management is complete tumor resection, but radiotherapy is reserved in cases of subtotal resection and multiple lesions. Locally aggressive nature of tumor and possibility of recurrence warrant regular follow-up.