title: Malignant gastrointestinal stromal tumor of the ampulla of Vater: a case report.
abstract: GIST is a rare neoplasm, the majority of GISTs are located in the stomach and small intestine. Most GISTs are diagnosed histopathologically after resection because of submucosal location. A 37-year-old female patient presented with a 2-weeks history of generalized weakness, nausea accompanied by intermittent passage of black, tarry stools. Esophagogastroduodenoscopy and ERCP showed a large round mass measuring 5 cm in diameter in the ampulla of Vater with ulcer crack. Endoscopic multiple biopsies from the mass including ulcer base were taken. Light microscopic findings showed spindle-shaped and epitheloid tumor cells having high cellularity and frequent mitotic figures. On immunohistochemical stainings, the tumor cells were positive for CD34 and smooth muscle actin. Based on these preoperative findings, a diagnosis of malignant GIST of the ampulla of Vater was made probably. After operation, immunohistochemical studies revealed positive reaction for c-kit and vimentin, as well as focally reactive for CD34 and smooth muscle actin. We report a case of GIST in the ampulla of Vater presenting with melena that was diagnosed preoperatively and postoperatively.
authors.affiliation: Department of Internal Medicine, Hallym University College of Medicine, Chuncheon, Korea.
authors.forename: Su Ho
authors.initials: SH
authors.lastname: Kim
authors.forename: Jong Hyeok
authors.initials: JH
authors.lastname: Kim
authors.forename: Gwang Ho
authors.initials: GH
authors.lastname: Baik
authors.forename: Ilhyun
authors.initials: I
authors.lastname: Baek
authors.forename: Taeho
authors.initials: T
authors.lastname: Hahn
authors.forename: Soon Ok
authors.initials: SO
authors.lastname: Oh
authors.forename: Jin Bong
authors.initials: JB
authors.lastname: Kim
authors.forename: Sang Hoon
authors.initials: SH
authors.lastname: Park
authors.forename: Woong Ki
authors.initials: WK
authors.lastname: Chang
authors.forename: Dong Joon
authors.initials: DJ
authors.lastname: Kim
authors.forename: Choong Kee
authors.initials: CK
authors.lastname: Park
authors.forename: Hye Rim
authors.initials: HR
authors.lastname: Park
mesh_terms: D000328:Adult; D014670:Ampulla of Vater; D003138:Common Bile Duct Neoplasms / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000175:diagnosis* / Q000473:pathology; D006801:Humans