Malignant peripheral nerve sheath tumor (MPNST) is a rare and aggressive type of cancer that originates in the cells surrounding the peripheral nerves. These tumors can occur anywhere in the body but are commonly found in the extremities, head, and neck regions. MPNSTs can cause pain, neurological deficits, and functional impairment, and may be associated with neurofibromatosis type 1 (NF1).