Clinical features and long-term outcomes of primary spinal malignant melanoma: a single center experience

Primary malignant melanomas are very rare tumors in the spinal canal. In this study, the authors review their experience in a series of seven patients with histologically proven primary spinal malignant melanoma (PSMM) and discuss the clinical features, treatment strategy, and long-term outcomes. Clinical data of seven patients with PSMM treated at a single institution were retrospectively analyzed. There were three male and four female patients, with a mean age of 44 years. The mean duration of illness was 5.4 months. The tumors showed hyperintensity in six cases on T1-weighted image (WI) and isointensity or hypointensity in five cases on T2WI. Gross total resection (GTR) of the tumor was achieved in two cases, and subtotal resection (STR) was achieved in five cases. Four STR patients underwent postoperative local radiation therapy. Postoperative MRI results showed no tumor recurrence in all four female patients after an average follow-up period of 64.5 months. Three male patients had tumor recurrence and dissemination after postoperative 14.7 months (8-24 months), and all died 16.3 months (10-25 months) after initial diagnosis. PSMM should be considered in the differential diagnosis of a middle-aged patient with spinal lesion if the tumor shows hyperintensity on T1WI and hypointensity or isointensity on T2WI on MRI. STR followed by radiotherapy is not excessively associated with deterioration of the final outcome compared to GTR. Our study suggests that PSMM might have female predominance in favorable outcome. Surgical resection followed by adjuvant radiotherapy and regular follow-up are recommended.