Malignant peripheral nerve sheath tumors (MPNSTs) are sarcomas on peripheral nerves or nerve sheath. These MPNSTs can occur on any cell type and differs from one to other. A sarcoma is regarded as MPNST only when it is raised on the peripheral nerve or it exists on neurofibroma. MPNSTs usually present as an enlarging palpable mass. Pain is a variable complaint. Rapid enlargement occurs more often in the setting of NF1 and should raise concern for malignant degeneration of a neurofibroma.
In Sweden All ages and both sexes may be affected by PNSTs. Sporadic MPNSTs are most common between 40 and 50 years of age, while those occurring in the setting of NF1 are diagnosed some 10 years earlier. In total, MPNSTs account for 5-10% of all soft tissue sarcomas.