title: Endoscopic diagnosis of gastrointestinal stromal cell tumors.
abstract: OBJECTIVE
  To outline the recommended course of action when a subepithelial lesion is encountered during upper endoscopy. It will focus on the endoscopic and endosonographic features common to gastrointestinal stromal tumors, and the optimal tests performed to confirm the diagnosis of a gastrointestinal stromal tumor.
  
  
  RESULTS
  The major recent finding of a mutation in the protooncogene c-kit which is unique to gastrointestinal stromal tumors has led to their reclassification as separate from other spindle cell tumors. Endoscopic ultrasound is a key component of the evaluation of submucosal lesions of the gastrointestinal tract, allowing determination of the wall layer of origin of the lesion and diagnostic sampling. Endosonographic features of gastrointestinal stromal tumors associated with high-risk lesions include size larger than 4-5 cm, irregular or invasive border, cystic spaces and malignant appearing lymph nodes. Endoscopic ultrasound-guided fine needle aspiration is generally adequate for tissue acquisition. Immunohistochemical analysis is performed on the tissue to differentiate gastrointestinal stromal tumors from other spindle cell neoplasms.
  
  
  CONCLUSIONS
  The clinical behavior of gastrointestinal stromal tumors is variable. Accurate preoperative endoscopic characterization of the lesion with fine needle aspiration is critical for treatment decisions and for an assessment of prognosis.
authors.affiliation: Oregon Health and Science University, Portland, Oregon 97239-3098, USA. rodrigue@ohsu.edu
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Rodriguez
authors.forename: Douglas O
authors.initials: DO
authors.lastname: Faigel
mesh_terms: D016099:Endoscopy, Gastrointestinal; D019160:Endosonography; D046152:Gastrointestinal Stromal Tumors / Q000175:diagnosis* / Q000473:pathology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry