Primary primitive neuroectodermal tumor of the small bowel: not just for kids

Primitive neuroectodermal tumor (PNET) is a subtype of small round cell tumor and is thought to represent a more differentiated variant within the Ewing sarcoma (ES) family.1 ES and PNET are indistinguishable on light microscopy and both typically express the 22q12 chromosomal translocation.2 Unlike ES, PNETs show neuroectodermal differentiation and are believed to originate from pluripotent neural crest cells. Intestinal bleeding and bowel obstruction have also been cited as presenting symptoms of a primary small bowel PNET.2-4 Given the capacity of the peritoneal cavity, patients often present late with these symptoms and at an advanced tumor stage.