胃肠道间质瘤的临床病理及免疫组化表达

目的：观察胃肠道间质肿瘤(gastrointestinal stromal tumor,GIST）临床病理特征及免疫组化表达，为临床诊断、治疗提供可靠依据。方法：采用常规病理切片HE染色，光镜观察，并行S－P法免疫组化Vimentin、CD34、SMA、Desmin、NF、S-100、EMA等标记物标记26例GIST。结果：26例GIST中，良性7例，恶性10例，低度恶性9例；发生于胃14例，小肠5例，回盲部2例，大肠和直肠5例；免疫组化Vimentin、CD34在瘤细胞中呈强阳性表达（阳性表达率分别为96．2％和84．6％），肌源性和神经源性标记物SMA、S－100呈散在细胞阳性表达（阳性表达率分别为26．9％和15．4％），而NF、EMA、Desmin均呈阴性表达。结论：GIST是一种源于原始间充质细胞的非定向分化的肿瘤，可伴有神经源性或／和肌源性分化，组织学上常以梭形细胞或上皮样细胞为主，具有类似肌源性或神经源性肿瘤的形态；临床手术切除前不易诊断，病理组织形态上易误诊为其它类型梭形细胞肿瘤；CD34和Vimentin对本瘤病理诊断具有较高的价值。

Clinicopathologic Analysis and Immunohistochemical Expression of Gastrointetinal Stromal Tumors

Objective:To observe clinicopathologic features and immmunohistochemical expression of gastrointestinal stromal tumors(GIST) and to provide some evidences for clinical diagnosis and therapy. Methods:The paraffin embedded specimens of 26 cases of GIST were studied by light microscopy,and labelled with Vimentin,CD 34 ,SMA,Desmin,NF,S-100,EMA et al markers.Results:In 26 cases of GIST, there are 7 cases benign, 10 cases malignant,9.14 cases low-grade malignant are found in the stomach,5 in the small intestine ,and 7 in the colo-rectum.The tumor cell in all the GIST showed obviously positive expressions of Vimentin,CD 34 (positive rate at 96.2%,84.6%,respectively);and sctattering cells showed positive expressions of SMA,S-100(26.9%,15.4% , repectively);but negative expression of NF, SMA and Desmin.All the patients were admitted to our hospital because of gastrointestinal carcinoma, leiomyofibroma or uncertain property of tumor. 15 cases of GIST were diagnosed for benign leiomyoma or neurofibroma(3cases), malignant or low-grade malignant leiomyoma and neurofibroma(11cases) , malignant hemangiopericytoma (1case) in the pathology ,and the rate of misdiagnosis was 57.7%. Conclusions:GIST is a kind of neoplasm of non-directive differentiation originated from primitive mesenchyme , sometimes with neurogenous or / and myogenous differentiation.The shape of tumor is usually dominated by fusiform cell or epithelioid cell in the histological morphology ,and is similar to morphology of neurogenous or / and myogenous cells.It is not easy to diagnose the tumors before excision clinically .The results suggest that the expressions of Vimentin and CD 34 be great valuable for diagnosing GIST, because GIST was easily diagnosed by mistake for other fusiform cell tumors in their morphology.