title: A Case of Extraskeletal Ewing's Sarcoma Arising from Duodenum.
abstract: Extraskeletal Ewing's sarcomas (EES) are rare. Recently, Ewing's sarcoma of the bone, primitive neuroectodermal tumor (PNET), Askin tumor and EES have been included into the family of Ewing's tumors, due to the overlapping features relating to their clinico-pathological and cytogenetic appearance. We experienced a case of an EES arising from the duodenum in a 14-year-old girl who presented with hematemesis and epigastric discomfort. A duodenal biopsy specimen revealed the infiltration of small round cells and rich vasculatures, with immunohistochemical finding of MIC-2 (CD99) (+), vimentin (+), CD56 (NCAM) (+), LCA (-), T-cell (-), B-cell (-), CD43 (-) and CD68 (-). She was treated with several cycles of multiagent chemotherapy, and achieved an initial partial response, but rapid progression of tumor followed, so she was treated with surgical excision. This is the first case report of an EES arising from the duodenum in the literature.
authors.forename: Sang Il
authors.initials: SI
authors.lastname: Kim
authors.forename: Yeon Hee
authors.initials: YH
authors.lastname: Park
authors.forename: Seong Jun
authors.initials: SJ
authors.lastname: Choi
authors.forename: Baek Yeol
authors.initials: BY
authors.lastname: Ryoo
authors.forename: Seung Sook
authors.initials: SS
authors.lastname: Lee
authors.forename: Hyun Bae
authors.initials: HB
authors.lastname: Son
authors.forename: Yo Ahn
authors.initials: YA
authors.lastname: Suh
authors.forename: Dae Han
authors.initials: DH
authors.lastname: Kim
authors.forename: Sung Ho
authors.initials: SH
authors.lastname: Kim
authors.forename: Kui Sung
authors.initials: KS
authors.lastname: Choi
authors.forename: Yoong Ju
authors.initials: YJ
authors.lastname: Kweon