Malignant transformation of spinal meningeal melanocytoma. Case report and review of the literature.

Meningeal melanocytomas are rare tumors and malignant transformation of these lesions is even rarer. The authors report on a case of a 57-year-old man who presented with a melanocytoma located at the L5-S1 level. After gross-total resection of the tumor, it recurred 1 year later as a malignant melanoma. In addition, multiple subcutaneous metastases were found at that time. The patient was treated with radiation therapy (5000 cGy). Five months later metastases in the liver and the left ninth rib were discovered. The pertinent literature is reviewed and disease criteria are presented to distinguish meningeal melanocytoma from malignant melanoma and from meningiomas or schwannomas containing melanotic pigment. Patients and investigators should be cautioned that a meningeal melanocytoma may recur and transform into a malignant melanoma.