Malignant peripheral nerve sheath tumor – how imaging can help

The malignant peripheral nerve sheath tumors (MPNST) are tumors originating from peripheral nerve sheath cells, which can originate de novo or even arise from pre-existing tumors, such as neurofibromas, ganglioneuromas or Schwannomas. These tumors represent approximately 5 – 10% of soft tissue sarcomas, with no recognized gender predilection. Among the risk factors for the development of these neoplasms are previous exposure to radiation and type 1 neurofibromatosis, in which patients have a 10% lifetime risk of developing an MPNST, as well as usually presenting them earlier when compared to sporadic cases. These patients often present with a rapidly growing mass that can cause local pain or focal neurological symptoms, with the proximal portion of the extremities being the most frequently affected sites . The aim of this presentation is to review the imaging characteristics of MPNSTs, focusing on their rhabdomyoblastic differentiation (malignant triton tumors) and the role of imaging methods in differentiating benign from malignant peripheral nerve sheath tumors.