title: Gastrointestinal stromal tumors of the stomach: CT findings and prediction of malignancy.
abstract: OBJECTIVE
  The purpose of this study was to identify predictors of malignancy on CT for the evaluation of gastrointestinal stromal tumors of the stomach.
  
  
  METHODS
  The medical records at our institution of 81 patients with a histologic diagnosis of gastrointestinal stromal tumor of the stomach were reviewed. Two radiologists retrospectively reviewed the CT findings by consensus with respect to lesion size, contour, tumor growth pattern, enhancing pattern, degree of enhancement, mesenteric fat infiltration, ulceration, calcification, lymphadenopathy, direct invasion to adjacent organ, and distant metastasis. Categoric variables were compared using the chi-square or Fisher's exact test. Multiple stepwise logistic regression analysis by means of forward selection was performed to determine significant predictors of high mitotic rate. Univariate analysis and multivariate analysis were also performed in a subgroup of 36 tumors with maximal diameter of 5 cm or smaller.
  
  
  RESULTS
  Size, presence of an ulcer, mesenteric fat infiltration, direct organ invasion, and metastasis were more frequently observed during univariate analysis in tumors with a high mitotic rate (p < 0.05). With stepwise logistic regression analysis, the size (odds ratio, 2.57; 95% CI; 1.42-4.67) was the only significant predictor of a high mitotic rate. In a subgroup of 36 tumors 5 cm or smaller, differentiation of benign from malignant tumors was not possible using CT.
  
  
  CONCLUSIONS
  Although presence of an ulcer, mesenteric fat infiltration, direct organ invasion, and metastasis were more frequently observed in tumors with a high mitotic rate, no CT feature, other than size, was found to have predictive value with respect to malignant gastrointestinal stromal tumors of the stomach.
authors.affiliation: Department of Radiology, Seoul National University Hospital, 28, Yongon-Dong, Chongro-gu, Seoul 110-744, South Korea.
authors.forename: Hyo-Cheol
authors.initials: HC
authors.lastname: Kim
authors.forename: Jeong Min
authors.initials: JM
authors.lastname: Lee
authors.forename: Kyoung Won
authors.initials: KW
authors.lastname: Kim
authors.forename: Seong Ho
authors.initials: SH
authors.lastname: Park
authors.forename: Se Hyung
authors.initials: SH
authors.lastname: Kim
authors.forename: Jae Young
authors.initials: JY
authors.lastname: Lee
authors.forename: Joon Koo
authors.initials: JK
authors.lastname: Han
authors.forename: Byung Ihn
authors.initials: BI
authors.lastname: Choi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D013274:Stomach Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D017154:Stromal Cells / Q000473:pathology*; D014057:Tomography, X-Ray Computed