title: [A clinical and immunohistochemical study on gastrointestinal stromal tumor].
abstract: OBJECTIVE
  As the relationship between gastrointestinal stromal tumors (GIST) and interstitial cells of Cajal had become clear, GIST is defined as CD117 positive mesenchymal tumors, and recognized as a new distinct entity among mesenchymal tumors presenting as gastrointestinal submucosal tumors (SMT). To evaluate GISTs in the category of SMTs, we analyzed mesenchymal SMTs immunohistochemically and clinicopathologically.
  
  
  METHODS
  Forty-five patients with mesenchymal SMTs, who received surgical or endoscopic resection were retrospectively analyzed for clinical parameters. Immunohistochemical staining for CD117, CD34, NSE, SMA, and S-100 was also performed.
  
  
  RESULTS
  Among 45 tumors, 41 (91.1%) expressed CD117 and were diagnosed as GIST. The most frequent location was the gastric body. Except esophageal location (73.3%), GISTs accounted for 100% of SMTs in the gastrointestinal tract. The mixed myoid-neural differentiated type and the spindle cell shape were most common. Metastasis was observed in 5 patients (11%). All of them had tumors larger than 5 cm and died. Their mean survival was 4.6 months.
  
  
  CONCLUSIONS
  GIST accounted for majority (91.1%) of SMTs. The presence of metastasis and tumor size at the time of diagnosis indicate poor prognostic factors. Immunohistochemical study is necessary for exact diagnosis of GIST.
authors.affiliation: Department of Internal Medicine, Research Institute of Life Science, Gyeongsang National University College of Medicine, Jinju, Korea. ojlee@nongae.gsnu.ac.kr
authors.forename: Eun Jung
authors.initials: EJ
authors.lastname: Lee
authors.forename: Ok Jae
authors.initials: OJ
authors.lastname: Lee
authors.forename: Tae Hyo
authors.initials: TH
authors.lastname: Kim
authors.forename: Woon Tae
authors.initials: WT
authors.lastname: Jung
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000737:chemistry* / Q000175:diagnosis / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis
chemical_list: D019009:Proto-Oncogene Proteins c-kit