Spinal malignant melanotic nerve sheath tumor with atypical magnetic resonance imaging findings: A case report

Malignant melanotic nerve sheath tumors (MMNSTs) are relatively rare, comprising <1% of all neoplastic peripheral nerve lesions. Here, we describe a 79-year-old male who presented with atypical magnetic resonance imaging (MRI) findings of an MMNST. A 79-year-old male presented with lower back pain, paraparesis, and bladder/bowel dysfunction. The MRI showed an intradural extramedullary (IE) lesion at the T9–T10 level with low-signal intensity on T1-weighted images (WI) and high intensity on T2-WI, which markedly enhanced with contrast. The IE nerve root involved with the tumor was completely removed surgically. The lesion was confirmed to be an MMNST. In the absence of metastases, adjuvant therapy was deemed unnecessary. One year later, the lesion has not recurred. A 79-year-old male patient presented with a T9–T10 MR intradural lesion that was pathologically proved to be an MMNST, which was treated with gross total surgical resection (i.e., removal of the involved nerve root alone).