目的探讨胃肠道间质瘤(GIST)的病理形态学和免疫组织化学特点。方法采用免疫组织化学SP法观察CD117、CD34、desmin、S-100、vimentin等蛋白在26例GISTs中的表达。结果肿瘤细胞形态多变和排列方式多样,基本细胞类型为梭形细胞和上皮样细胞。免疫组化染色CD117和CD34多为弥漫强阳性,阳性率分别为76.9%和73.1%,两者表达呈正相关;Desmin、S-100及vimentin阳性率分别是26.9%、11.5%和69.2%。结论CD117、CD34在GIST免疫组织化学染色阳性率较高,可作为确诊的参考。 Objective To investigate the pathomorphological and immunohistochemical features of gastrointestinal stromal tumor (GIST). Methods The expression of CD117, CD34, desmin, S-100, and vimentin proteins in 26 GISTs was detected by SP immunohistochemistry. Results The morphology of the tumor cells varied and the arrangement was diverse. The basic cell types were spindle cells and epithelioid cells. Immunohistochemical staining showed that CD117 and CD34 were diffusely positive, the positive rates were 76.9% and 73.1% respectively. There was a positive correlation between the two expressions. The positive rates of Desmin, S-100 and vimentin were 26.9%, 11.5% and 69.2%, respectively. Conclusion The positive rate of immunohistochemical staining of CD117 and CD34 in GIST is high, which can be used as a reference for diagnosis.