title: [A case of primary extragastrointestinal stromal tumor presenting as peritoneal dissemination].
abstract: Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract, but also occurs at a lower frequency in extra-gastrointestinal regions such as omentum, mesentery, retroperitoneum and undefined abdominal sites. This tumor is called extragastrointestinal stromal tumor (EGIST). EGIST is mostly diagnosed as a cystic mass, but rarely occurs as a disseminated abdominal tumor. We experienced a 70-year-old man with primary EGIST presenting as peritoneal dissemination. Abdominal CT showed diffuse peritoneal thickening with a large amount of ascites, but no definite mass lesion. Laparoscopic biopsy was performed and histologic findings showed tumor composed of epithelioid cells. In the results of immunohistochemical stains, the tumor showed positive reactivity with CD117 (c-kit), CD34, vimentin and actin, but negative reactivity with desmin and S-100 protein. On account of unresectability and histologic parameters of malignant behavior, he was started on imatinib.
authors.affiliation: Department of Internal Medicine, The Catholic University of Korea College of Medicine, Seoul, Korea.
authors.forename: Hong Jun
authors.initials: HJ
authors.lastname: Yang
authors.forename: Tae Ho
authors.initials: TH
authors.lastname: Kim
authors.forename: Min Kyoung
authors.initials: MK
authors.lastname: Park
authors.forename: Chang Hoon
authors.initials: CH
authors.lastname: Lim
authors.forename: Kee Hyun
authors.initials: KH
authors.lastname: Lee
authors.forename: Chang Whan
authors.initials: CW
authors.lastname: Kim
authors.forename: Sok Won
authors.initials: SW
authors.lastname: Han
authors.forename: Jean A
authors.initials: JA
authors.lastname: Kim
mesh_terms: D000199:Actins / Q000378:metabolism; D000368:Aged; D018952:Antigens, CD34 / Q000378:metabolism; D046152:Gastrointestinal Stromal Tumors / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D010535:Laparoscopy; D008297:Male; D010534:Peritoneal Neoplasms / Q000175:diagnosis* / Q000556:secondary; D049268:Positron-Emission Tomography; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D014057:Tomography, X-Ray Computed; D014746:Vimentin / Q000378:metabolism
chemical_list: D000199:Actins; D018952:Antigens, CD34; D014746:Vimentin; D019009:Proto-Oncogene Proteins c-kit