Malignant nerve sheath tumor of the spinal accessory nerve: a unique presentation of a rare tumor.

Background: Malignant peripheral nerve sheath tumors (MPNSTs), sarcomas originating from tissues of mesenchymal origin, are rare in patients without a history of neurofibromatosis.

Case Report: We report a case of an MPNST of the spinal accessory nerve, unassociated with neurofibromatosis, which metastasized to the brain. The tumor, originating in the intrasternomastoid segment of the spinal accessory nerve, was removed.