胃肠道间质瘤58例临床病理分析

 分析胃肠道间质瘤（GIST）的形态特点和免疫组织化学特征，探讨肿瘤的组织来源和分型。方法 对58例GIST进行光镜观察，用EnVision二步法免疫组织化学方法检测波形蛋白、CD117（c-Kit）、CD34等抗原标记物在肿瘤中的表达情况。结果 58例GIST占同期消化系统间叶性肿瘤的86.6 %（58／67）；其中梭形细胞为主者41例，伴有上皮样细胞者12例，单纯由上皮样细胞组成者5例，瘤细胞呈长、短梭形和圆形，胞质弱嗜酸，常见核端空泡，有时呈印戒样或透明细胞样；排列呈漩涡状、栅栏状或弥漫性巢状。免疫组织化学显示肿瘤组织中抗原标记物表达阳性率波形蛋白为100 %（58／58），CD117 94.8 %（55／58），CD34 79.3 %（46／58）。结论 GISTs是消化道最常见的间叶性肿瘤，光镜形态与真性肌源性和神经源性肿瘤极为相似，CD117、CD34等免疫标记物可对其作出正确诊断，GIST可能起源于多潜能的、卡哈尔间质细胞样的前体细胞。

Clinicopathological analysis of 58 cases of gastrointestinal stromal tumor

Objective To investigate the clinical presentation, morphological features, immunohistochemical staining of the gastrointestinal stromal tumor (GIST), and its histogenesis as well. Methods The morphologic characteristics of GISTs were studied in 58 cases using light microscopy. The expression of c-kit(CD117), CD34 and vimentin were detected in all of the cases with EnVision staining. Results Among 58 cases of GISTs, 41 were spindle cell type, 5 epithelioid cell type and 12 mixture type, equivalent to 86.6 %(58 of 67) of all of the mesenchymal tumors of gastrointestinal tract admitted in the same period. The epithelioid cell type tumors were mainly composed of the epitheloid cells, predominantly short spindle, oval or round in pattern, with an overall eosinophilic cytoplasm by hematoxylin-eosin stain. Focal cytoplasmic vacuolization was often seen. Sometimes signet-ring like cells and cells with a clear cytoplasm were seen in the epithelioid stromal tumor. The tumor cells arranged in interlacing fascicles forming whorls or sometimes cell clusters. All of the 58 stromal tumors were strongly positive for vimentin (100 %), 55 out of 58 tumors positive for CD117 (94.8 %) and 46 out of 58 positive for CD34(79.3 %). Some cases also expressed SMA, actin, S-100 and MBP. Conclusions GISTs were the most common mesenchymal tumor seen in the gastrointestinal tract. Under light microscope, the morphology of stromal tumors sometimes looks like a leiomyoma or Schwannoma. The application of immunohistochemical markers (particularly CD117 and CD34) is considered necessary for the differential diagnosis. GISTs may originate from the pluripotential precursor cells like the interstitial cells of Cajal.