Incidental Detection of Primary Spinal Malignant Melanoma before Central Nervous System Dissemination.

The present case illustrates the incidental detection of a primary malignant melanoma of the thoracic spinal cord before central nervous system dissemination. A 54-year-old female fell down and bruised the thoracolumbar region. The patient visited a local doctor and underwent magnetic resonance imaging (MRI) of the thoracic and lumbar spine to rule out vertebral fractures. MRI revealed no vertebral fracture, but an intradural extramedullary mass was observed at the T12 level. She was referred to our hospital in October 2008. MRI showed that the mass appeared hyperintense on T-weighted images and hypointense on T-weighted images. T-weighted MRI with gadolinium showed a mild homogeneous enhancement of the lesion. The patient underwent laminectomy at T11-L1, along with the complete removal of the tumor, and she exhibited no remarkable symptoms after surgery. Histopathological examination confirmed the diagnosis of malignant melanoma. Malignant melanoma was not detected elsewhere in the body. Neither radiotherapy nor chemotherapy was performed after surgery. Her neurological examination was unremarkable 5 years after the surgery and no tumor recurrence was detected. The present case suggests that patients with primary spinal malignant melanoma may survive >5 years without recurrence after complete surgical removal of the tumor alone. Complete removal of the tumor before central nervous system dissemination may be critical for treatment in such cases. Precise diagnosis via MRI may increase the detection of primary spinal malignant melanoma before central nervous system dissemination, thus facilitating prompt surgical removal, improving the prognosis of patients.