Huge peripheral primitive neuroectodermal tumor of the small bowel mesentery at nonage: A case report and review of the literature.

Extraskeletal Ewing's sarcoma/peripheral primitive neuroectodermal tumor (E-EWS/pPNET) is a rare aggressive malignant small round cell tumor. In this report, we present the case of a 15-year-old boy who suffered from acute abdominal pain accompanied by hematemesis and melena, and was eventually diagnosed with E-EWS/pPNET. To date, there have been only five reported cases of E-EWS/pPNET of the small bowel including the patient in this report.