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 Australia Fifty two of 1254 NF1 patients developed MPNST, with MPNST also occurring in 2/181 cases of schwannomatosis and 2/895 NF2 patients. Three cases were also noted in TP53 mutation carriers. However, there were no cases amongst 5727BRCA1/2carriers and first degree relatives, 2029 members from Lynch syndrome families, nor amongst 447 Familial Adenomatous Polyposis, 202 Gorlin syndrome, nor 87 vHL cases.