胃肠道间质瘤的光镜、免疫组织化学和超微结构的观察

目的 研究胃肠道间质瘤（GISTs）的光镜,电镜形态特点和免疫组织化学在诊断中的价值,探讨肿瘤的组织来源和分型。方法 对GISTs进行光镜和超微结构的观察,用EnVision二步法免疫组织化学方法检测波形蛋白,CD117（c-kit),CD34等8种抗原标记物在肿瘤中的表达情况。结果 65例GISTs占同期消化系统间叶性肿瘤的85．5％（65／76）;其中梭形细胞为主的有46例,伴有上皮样细胞的有13例,单纯由上皮样细胞组成的有6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;排列呈旋涡状,栅栏状或弥漫性巢状。超微结构表现出树枝样突起,神经内分泌颗粒,桥粒样连接等神经分化特点,或（和）胞质内出现密斑,密体等肌性分化。免疫组织化学显示肿瘤组织中抗原标记物表达阳性率波表蛋白为100％（65／65）,CD11793．8％（61／65）,CD3478．5％（51／65）。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,电镜和CD117,CD34等免疫标记物配合使用可对其做作出正确诊断,GISTs可能起源于多潜能的,卡哈尔间质细胞样的前体细胞。

Study of gastrointestinal stromal tumors by light microscopy,electron microscopy and immunohistochemistry

Objective To investigate the morphological features, immunohistochemical speciality of the gastrointestinal stromal tumors (GISTs), and its histogenesis as well Methods The morphologic characteristics of GISTs were studied in 65 cases using light microscopy and 17 cases by electron microscopy The expression of c kit (CD117), CD34, vimentin, SMA, actin, desmin, S 100 and MBP were detected in all the cases with EnVision TM staining Results Among 65 cases of GISTs, 46 were spindle cell type, 6 epithelioid cell type and 13 mixture type, equivalent to 85 5% (65 of 76) of all of the mesenchymal tumors of gastrointestinal tract admitted in the same period The epithelioid cell type tumors composed of mainly the epithelioid 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 Electronic microscopy showed the presence of interdigitating cell processes, in some areas, synapse like structure and numerous desmosome like junctions as well as a few gap junctions and small round neurosecretory granules There were also abundant intermediate filaments and thin filaments of actin type with longitudinal condensations (dense bodies) All of the 65 stromal tumors were strongly positive for vimentin (100%), 61 out of 65 tumors positive for CD117(c kit) (93 8%) and 51 out of 65 positive for CD34 (78 5%) Some cases also expressed SMA, actin, S 100 and MBP Conclusions GISTs were the most frequent mesenchymal tumor seen in the gastrointestinal tract Under light microscope, the morphology of stromal tumors looks sometimes like a leiomyoma and Schwannoma The application of immunohistochemical markers (particularly CD117 and CD34) and ultrastructural study are considered necessary for the differential diagnosis GISTs may originate from the pluripotential precursor cells like the interstitial cells of Cajal