A small round cell tumor that lacks morphologic, immunohistochemical, and electron microscopic evidence of neuroectodermal differentiation. It represents one of the two ends of the spectrum called Ewing's sarcoma/peripheral neuroectodermal tumor. It affects mostly males under age 20, and it can occur in soft tissue or bone.
Tumours of this family (peripheral primitive neuroectodermal tumours [PNETs]) have been reported in the pancreas
Movahedi-Lankarani S, Hruban RH, Westra WH, Klimstra DS (2002)
. These small round blue cell tumours have rearrangement of the EWSR1 gene, usually a EWSR1-FLI1 fusion with t(11;22) translocation, and are strongly immunoreactive for CD99. They often express synaptophysin, and occasionally keratins. Before making a diagnosis of Ewing sarcoma, other small round blue cell tumours and pancreatic neuroendocrine neoplasms must be excluded
Primitive neuroectodermal tumors of the pancreas: a report of seven cases of a rare neoplasm.
Am J Surg Pathol 26: 1040-7
Hruban RH, Pitman MB, and Klimstra DS
Tumors of the Pancreas. Armed Forces Institute of Pathology
Washington, DC 2007
Bosman FT, Carneiro F, Hruban RH, Theise ND (Eds.)
WHO Classification of Tumours of the Digestive System.
International Agency for Research on Cancer: Lyon 2010