Cutaneous metastases of malignant peripheral nerve sheath tumor: Ineffectiveness of intralesional methotrexate

Malignant peripheral nerve sheath tumor (MPNST) is an uncommon, aggressive sarcoma that arises from peripheral nerves and metastasizes hematogenously, most often to lung and bone.1 Approximately half of MPNSTs arise from plexiform neurofibromas in patients with neurofibromatosis type I (NF1).1 The remaining half occur sporadically, 10% of which arise from previously irradiated tissue.1 The epithelioid variant of MPNST is uncommon, accounting for less than 5% of cases.1 The most important aspect of treatment for MPNST is achieving clear surgical margins, as survival decreases dramatically with positive margins.