Clinical and Pathological Analysis of Gastrointestinal Stromal Tumors

ObjectivesTo evaluate the diagnosis of gastrointestinal stromal tumors(GISTs) and explore the significance of immunohistochemical techniques in their diagnosis as well as the principle of treatment.MethodsForty seven patients with GISTs were treated by operation from 1990 to 2001.Their clinicopathological data were collected and analyzed retrospectively. The morphologic characteristics of GISTs were studied by using light microscopy. The expressions of 6 antigen markers-CD 117 , CD 34 , vimentin, S 100, MBP and HHF35 in GISTs were detected by S P immunohistochemical method.Results27 cases of GISTs were spindle cell type,4 were epithelioid cell type and 4 belonging to mixture type,equivalent to 74.4%(35 /47)of all mesenchymal tumors in gastrointestinal tract. The positive expression rates of antigen markers in 35 GISTs were: vimentin(35/35,100%),CD 117 (31/35,88.5%)and CD 34 (25/35,71.4%).ConclusionGISTs are the most frequent mesenchymal tumors seen in the gastrointestinal tract. Under light microscope, morphology of stromal tumors looks sometimes like a leiomyoma /Schwannoma. Correct judgment can be made if immunohistochemical markers(particularly CD 117 and CD 34 )are used to help the differential diagnosis. Tumor size, nuclear mitotic activity and atypia of cells can serve as the essential criteria in differentiation among benign, borderline and malignant GISTs.