Post-radiation intramedullary malignant peripheral nerve sheath tumor

Area of Science:

• Neuro-oncology
• Spinal Cord Pathology
• Radiation Oncology

Background:

• Malignant peripheral nerve sheath tumors (MPNSTs) are rare, aggressive neoplasms. Intramedullary spinal cord tumors are uncommon, with MPNSTs within the cord being exceptionally rare.
• A 50-year-old male presented with progressive tetraparesis, attributed to a C4-C5 intramedullary lesion identified via MRI.
• The patient had a history of childhood irradiation for tonsillitis, followed by laryngeal cancer and permanent tracheotomy, suggesting a potential link to radiation-induced neoplasms.

Observation:

• Surgical exploration revealed a friable, intramedullary neoplasm at C4-C5, with no clear cleavage plane, necessitating subtotal resection.
• Intraoperative diagnosis was inconclusive; however, subsequent histological examination confirmed an intermediate-grade MPNST with schwannian differentiation.
• No adjuvant radiotherapy was administered post-surgery.

Findings:

• The case represents a rare instance of intramedullary MPNST, distinct from more common dural-based or paraspinal tumors.
• Histological and ultrastructural analysis confirmed schwannian differentiation, aligning with peripheral nerve sheath tumor origins.
• The patient succumbed to pneumonial complications nine months post-surgery.

Implications:

• This case supports the possibility that spinal cord irradiation may induce intramedullary schwannosis, potentially leading to malignant transformation into MPNST.
• It adds to the limited evidence associating prior radiation exposure with the development of spinal cord tumors.
• Further research is warranted to elucidate the mechanisms of radiation-induced spinal cord neoplasms and their management.