title: Peripheral primitive neuroectodermal tumor with osseous component of the small bowel mesentery: a case study.
abstract: A case of peripheral primitive neuroectodermal tumor of the small bowel mesentery with osseous component is reported. A 23-year-old man was admitted to our hospital because of acute severe abdominal pain. Abdominal computed tomography revealed a large solid and cystic, oval shaped mass, measuring 11.0×6.0 cm in the pelvic cavity. Histologically the resected lesion consisted of sheets of undifferentiated small round cells forming Homer-Wright rosettes and perivascular pseudorosettes, and showed areas of osteoid and bone formation. Immunohistochemical studies revealed that tumor cells expressed positivity against CD99 (MIC2), CD57, neuron-specific enolase, and vimentin. Fluorescence in situ hybridization study revealed Ewing sarcoma breakpoint region 1 (EWSR1) gene rearrangement on chromosome 22q12. To the authors' knowledge this is the first documentation of a peripheral neuroectodermal tumor with osteoid and bone formation of the small bowel mesentery.
authors.affiliation: Department of Pathology, Inha University Hospital, Inha University School of Medicine, Incheon, Korea.
authors.forename: Joon Mee
authors.initials: JM
authors.lastname: Kim
authors.forename: Young Chae
authors.initials: YC
authors.lastname: Chu
authors.forename: Chang Hwan
authors.initials: CH
authors.lastname: Choi
authors.forename: Lucia
authors.initials: L
authors.lastname: Kim
authors.forename: Suk Jin
authors.initials: SJ
authors.lastname: Choi
authors.forename: In Suh
authors.initials: IS
authors.lastname: Park
authors.forename: Jee Young
authors.initials: JY
authors.lastname: Han
authors.forename: Kyung Rae
authors.initials: KR
authors.lastname: Kim
authors.forename: Yoon-La
authors.initials: YL
authors.lastname: Choi
authors.forename: Taeeun
authors.initials: T
authors.lastname: Kim
keywords: EWSR1; Intestine, small; Metaplasia; Neuroectodermal tumor, primitive, peripheral; Osteogenesis