Extraosseous Ewing's sarcoma of the pancreas.

The Ewing's family of tumors (EFT) comprises a molecularly defined group of "small round blue cell tumors", consisting of Ewing's sarcoma of bone (ESB), extraosseous Ewing's sarcoma (EES), peripheral primitive neuroectodermal tumor (pPNET), and Askin's tumor. Characteristic translocations that disrupt the EWSR1 gene located at 22q12 create novel fusion genes that are central to the pathogenesis. The EFT also shares certain clinical characteristics, such as a peak incidence during the teenage years, a tendency to spread rapidly, and responsiveness to the same chemotherapeutic regimens and radiation therapy. Nearly all patients have occult disseminated disease at diagnosis; hence, chemotherapy is routinely used. Improvements in multimodality treatment have had a dramatic impact on outcomes. EES/pPNET has been reported in a variety of sites, including the pancreas, though this is extremely rare. We describe a case of pancreatic EES/pPNET in a 35-year-old woman and provide a brief review of the relevant literature.