MPNSTs represent about 5% of all sarcomas and may arise from a peripheral nerve or a pre-existing neurofibroma; in about 50% of cases, these tumors arise in the context of NF1, while in the remaining cases they appear to be sporadic (40% of cases) or associated with a previous history of radiation [1,4,6,73,74,75]. The gene discussed is NF1; the disease is plexiform neurofibroma.