Malignant Peripheral Nerve Sheath Tumor
MPNST; Malignant schwannoma; Neurofibrosarcoma
Malignant peripheral nerve sheath tumors (MPNST) are tumors arising from the peripheral nerves with differentiation toward nerve sheath components. MPNST are often associated with neurofibromatosis type 1 (NF1; von Recklinghausen disease) or can occur sporadically. In addition, they may arise de novo or in preexisting benign peripheral nerve sheath tumors. The cell of origin has been postulated to be a neural crest cell. The tumors predominantly occur in the major nerve trunks of proximal extremities, the trunk, head, and neck region of adults or rarely children. In addition to NF1, the tumors may also be associated with previous radiation exposure. The tumors can show a wide morphologic spectrum and lack specific immunohistochemical or molecular characteristics. In addition, MPNST can contain areas of divergent differentiation including mesenchymal (rhabdomyosarcoma, osteosarcoma, chondrosarcoma, angiosarcoma) or...