title: Endosonographic differentiation of benign and malignant stromal cell tumors.
abstract: BACKGROUND
  Endosonography (EUS) is a valuable technique for diagnosing gastrointestinal stromal cell tumors. However, EUS features that are predictive of malignancy in these tumors have not been defined.
  
  
  METHODS
  Videotapes and photographs of EUS examinations performed prior to surgical resection of 35 stromal cell tumors (9 malignant) were blindly reviewed by a single examiner. EUS features associated with malignancy were determined. Interobserver agreement in interpreting these features was then measured among a panel of five expert endosonographers who judged EUS videotapes of 35 resected stromal cell tumors (10 malignant).
  
  
  RESULTS
  Stepwise logistic regression analysis demonstrated that tumor size (diameter > 4 cm), irregular extraluminal border, echogenic foci, and cystic spaces were independently associated with malignancy in stromal cell tumors (p < 0.05). Interobserver agreement for irregular extraluminal border, echogenic foci, and cystic spaces, as measured by mean kappa statistic, was 0.43, 0.39, and 0.28, respectively. For the five experts, the sensitivity for detecting malignancy ranged between 80% to 100% when at least two of the three features were judged to be present. The likelihood of finding malignancy ranged between 0% to 11% for the experts when all three features were judged absent.
  
  
  CONCLUSIONS
  Tumor size and certain EUS features are useful for predicting malignancy in stromal cell tumors. Absence of these features indicates benign disease. Agreement among experts in interpreting these EUS features is fair to moderate.
authors.affiliation: Case Western Reserve University, Cleveland, OH, USA.
authors.forename: A
authors.initials: A
authors.lastname: Chak
authors.forename: M I
authors.initials: MI
authors.lastname: Canto
authors.forename: T
authors.initials: T
authors.lastname: Rösch
authors.forename: H J
authors.initials: HJ
authors.lastname: Dittler
authors.forename: R H
authors.initials: RH
authors.lastname: Hawes
authors.forename: T L
authors.initials: TL
authors.lastname: Tio
authors.forename: C J
authors.initials: CJ
authors.lastname: Lightdale
authors.forename: H W
authors.initials: HW
authors.lastname: Boyce
authors.forename: J
authors.initials: J
authors.lastname: Scheiman
authors.forename: S L
authors.initials: SL
authors.lastname: Carpenter
authors.forename: J
authors.initials: J
authors.lastname: Van Dam
authors.forename: M L
authors.initials: ML
authors.lastname: Kochman
authors.forename: M V
authors.initials: MV
authors.lastname: Sivak
mesh_terms: D003937:Diagnosis, Differential; D019160:Endosonography / Q000379:methods*; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000000981:diagnostic imaging*; D006801:Humans; D007889:Leiomyoma / Q000000981:diagnostic imaging*; D007890:Leiomyosarcoma / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D016017:Odds Ratio; D010781:Photography; D011237:Predictive Value of Tests; D012044:Regression Analysis; D017154:Stromal Cells / Q000000981:diagnostic imaging; D014741:Video Recording