Gastrointestinal Stromal Tumors :A Morphologic and Immunohistochemical Study of 69 Cases

Objective:To investigate the morphological and immunohistochemical characteristics of gastrointestinal stromal tumors(GIST).Methods:69 cases of GISTs were investigated with clinicopathological observation and immunohistochemical analysis.Results:Of 69 cases,9 (13.0%)were benign,25 (36.2%)were bordline and 35(50.8%) were malignant.According to the cell types,46 cases were spindle cells, 19 cases were both spindle and epithelioid cells and 4 cases were epithelioid cells only.Immunohistochemical results showed as follows,65 cases (94.2%) were stained strongly with CD117;58(84.1%)were postive to CD34;16(23.2%)cases were stained with the S 100 protein,focally and weakly;14 cases(20.3%) were locally postive to SMA;only 3 cases(4.3%) were postive to desmin.Conclusion:Most GIST were malignant. CD117 is a useful marker to recognize GIST.The rate of CD34 positivity is higher in GIST and this may be helpful to the diagnosis.