胃肠间质瘤的临床病理及其免疫组织化学特征探讨

Clinicopathologic and Immunohistochemical Study on 34 Cases of Gastrointestinal Stromal Tumors

目的探讨胃肠间质瘤(GIST)的诊断标准、良恶性参考指标和预后因素。方法对34例GIST的临床表现、病理组织形态进行观察,应用免疫组织化学Envision法检测其CD117、CD34、a-SMA、S-100蛋白等的表达状况,并结合随访资料,对其生物学行为进行分析。结果GIST患者平均年龄58.9岁。最常见症状为腹痛和消化道出血。大体上肿瘤境界清楚,切面灰白,部分区可见出血、坏死囊性变等继发性改变。镜下梭形细胞25例,上皮样细胞4例,梭形或上皮样细胞5例。CD117和CD34多弥漫强阳性。阳性率为94.1%、79.4%。a-SMA、S-100阳性率分别为29.4%、35.3%。34例GIST中,良性7例,交界性16例,恶性11例。良性与交界性随访23例健在,恶性11例随访9例,3例无瘤生存,4例复发与转移,2例死亡。结论GIST好发中老年,瘤细胞形态多变,排列结构多样。免疫组织化学特征CD117、CD34阳性。肿瘤临床和病理形态、CD117和CD34表达是诊断GIST的要点。肿瘤直径大于5cm,核分裂像大于5/50HPF可作为良恶性参考指标。肿瘤性坏死、核分裂大于5/50HPF及肿瘤大小是预后的重要因素。

Objective To investigate the diagnostic crietria of gastrointestinal stromal tumors （GIST） and the reference parameters for malignancy and to explore the prognostic factors. Methods 34 cases of GIST was evaluated. The expression of CD117 ,CD34 ,a-SMA ,S-100 was detected by immunohistochemisty method of Envision. Clinical data including follow-up information were also examed. Results The average age was 58.9 years. The most common symptoms were vague pain and GI bleeding. Grossly of their middle were grayish, some of them were of soft consistency often with hemorrhage, cystification or necrosis. Microscopically. The tumors were composed of spindle cells （25 cases）, epithelioid cells （ 5 cases） or of both cells （ 5 cases ）. CD117 and CD34 showed diffuse strong expression. The positive rates were 94.1% and 79.4% respectively, a-SMA,S-100 show low expression, the positive rates were 29.4% and 35.3% respectively. Seven cases were benign, 16 cases borderline and 11 cases malignant. Follow-up of 23 cases with benign and borderline tumors found patients alive without tumor, In the malignant group,3 cases were alive without tumor,4 cases developed recurrence or metastasis, and. 2 cases died of tumor. Conclusion GIST predominantly occur in middle age or old patients. The tumors have varied cell types and different arrangements. Positive expression of CD117 and CD34 and morpholigic chacteristics are the diagnostic criteria of GIST. Larger than 5 cm in diametor and more than 5 mitotic activity in 50HPF is the criteria to differentiate benign and malignant GIST. Necrosis ,size of tumor and mitotic activity is the prognostic factors.