Published online Aug 26, 2022. doi: 10.12998/wjcc.v10.i24.8735
Peer-review started: March 21, 2022
First decision: May 30, 2022
Revised: June 11, 2022
Accepted: July 16, 2022
Article in press: July 16, 2022
Published online: August 26, 2022
Processing time: 147 Days and 22.5 Hours
A malignant melanotic nerve sheath tumor (MMNST), previously known as a melanotic schwannoma, is a rare variant of a peripheral nerve sheath tumor composed of Schwann cells with melanotic differentiation. Only a few reports of spinal MMNST have been reported.
In the first case, a 58-year-old woman presented with a history of low back pain and paresthesia. Magnetic resonance imaging (MRI) and computed tomography (CT) of the lumbar spine revealed an intradural extramedullary mass lesion with amorphous linear calcification. Complete tumor resection was performed and histological examination revealed a psammomatous melanotic schwannoma. In the second case, a 72-year-old man presented with low back pain and paresthesia. MRI of the thoracolumbar spine revealed an intramedullary mass lesion at the T11 vertebral body level. The mass lesion was hypointense on T2WI and hyperintense on T1WI. Tumor resection was performed and the histologic result was melanotic schwannoma.
MMNST should be considered in the differential diagnosis when calcification or melanin is seen in an intradural spinal tumor.
Core Tip: Spinal malignant melanotic nerve sheath tumor (MMNST) are rare entities. We report two cases of spinal MMNSTs with or without psammomatous bodies. These cases highlight the importance of considering these rare entities when there are characteristic imaging findings such as the presence of intra-lesional T1-hyperintensity or calcification in intradural spinal tumors.