NF1 and neurofibromatosis: Malignant peripheral nerve sheath tumors (MPNSTs) are rare spindle cell sarcomas arising from peripheral nerve cells, including Schwann cells.[1] They account for 5% to 10% of all malignant STSs, and out of this, half are associated with neurofibromatosis type 1 (NF1) and less commonly with NF2.[2,3] MPNST can be occurred in any part of the body, especially the trunk and extremities.[4] Because of morphological and immunohistochemical complexity, especially outside the NF1 context, the diagnosis of MPNST remains challenging.