Introduction: Malignant peripheral nerve sheath tumor (MPNST) is a type of connective tissue cancer, which may also have genetic backgrounds. More than half of patients have neurofibromatosis. The treatment of this tumor is a combination of surgery, radiotherapy, and chemotherapy. As usual, the tumor may be present anywhere with several manifestations. Case Presentation: A 4-year old boy presented with sweating and pain in the right forearm that was diagnosed with MPNST developed in the paravertebral region after laboratory and radiographic evaluation. Conclusions: The patient was treated successfully and followed up for one year without any complications.