Malignant peripheral nerve sheath tumor: Transformation in a patient with neurofibromatosis type 2.

Malignant peripheral nerve sheath tumor (MPNST) is a rare soft-tissue sarcoma with an unfavorable prognosis and limited therapeutic options. MPNSTs can be sporadic, but are often associated with neurofibromatosis (NF) 1 and usually arise from preexisting neurofibromas. MPNSTs in patients with NF2 have been reported in only exceedingly rare cases, and the mechanisms underlying transformation into an MPNST have not been fully elucidated. Here, we describe the clinicopathological and genomic features of a peripheral nerve sheath tumor (PNST), with a primary diagnosis of a neurofibroma, as it transforms into a high-grade MPNST in the context of NF2.