胃肠间叶源性肿瘤210例临床病理及免疫组织化学分析

Gastrointestinal mesenchymai tumors：a clinicalpathologic and immunohistochemical study of 210 cases

目的分析胃肠间叶源性肿瘤（GIMT）的临床病理及免疫组织化学（免疫组化）特征，探讨各项诊断指标在鉴别诊断中的价值。方法对北京大学人民医院原病理诊断为GIMT的病例进行回顾性分析，通过连续切片CD117、CD34、Desmin、SMA、PS100五联染色的方法观察免疫组化表型，结合临床、病理资料及苏木精．伊红染色，重新确认诊断。结果210例GIMT经复习后，确诊为胃肠间质瘤（GIST）127例（60．5％），平滑肌（肉）瘤33例（15．7％），神经源性肿瘤27例（12．8％），其他GIMT23例（11．0％）。GIST与平滑肌肿瘤患者男女性别比例相当，神经源性肿瘤和其他GIMT男性高于女性。GIST的好发部位依次是胃（51．2％）、小肠（19．7％）、食管（11．0％）、结直肠（10．2％）；平滑肌（肉）瘤好发部位为食管（15／33，45．5％），神经源性肿瘤好发于腹膜后（20／27，74．1％）。GIsT常见的临床首发症状依次为消化道出血36例（28．3％）、腹痛27例（21．3％）、腹部包块24例（18．9％），GIST之外的GIMT均无消化道出血的首发症状。79．5％的GIST和72．7％的平滑肌（肉）瘤肿瘤局限；33．3％的神经源性肿瘤侵及邻近器官或组织；GIST之外的GIMT均无远处转移。GIST细胞形态中梭形细胞占72．5％，上皮样细胞占11．8％，多形性细胞占15．7％；平滑肌（肉）瘤的梭形细胞占94．0％。GIST免疫组化CD117染色阳性率93．7％，CD34阳性率69．3％，Desmin阳性率13．4％，SMA阳性率12．6％，PS100阳性率10．2％。平滑肌（肉）瘤Desmin阳性率78．5％、SMA阳性率63．6％，而CD117、CD34和PS100阴性。神经源性肿瘤88．9％为PS100弥漫强阳性表现。结论GIMT以GIST为主，GIST与平滑肌（肉）瘤、神经源性肿瘤在首发症状、好发部位、生物学行为和免疫表型等方面具有一定的差异，免疫组化检测是GIMT鉴别诊断的重要手段。

Objective To study the clinicalpathologic and immunohistochemical features of gastrointestinal mesenchymal tumors （GIMTs）, and to investigate the value of molecular markers in GIMTs clinical differentiation diagnosis. Methods The clinical and pathological data of 210 cases of GIMTs, collected from Jan. 1987 to Dec. 2005 in our hospital, were investigated retrospectively. GIMTs were rediagnosed by using standard immunostaining technique in paraffin-embedded tissue. The expression level of CD117, CD34, Desmin, SMA and PS100 were detected by immunohistochemical method. Results Among 210 cases of GIMTs, 127 cases were Gastrointestinal stromal tumors（GISTs） （60.5%）, 33 leiomyomas and leiomyosarcomas （15.7%）, 27 neurogenic tumours （12.8%）, and 23 miscellaneous tumors （11.0%）. The incidences of GIST, leiomyoma and leiomyosarcoma were similar among men and women. Men were more likely to develope neurogenic tumors and miscellaneous tumors than women. Of all the GISTs, 51.2% cases originated from stomach, 19.7% from small intestine, 11.0% from esophagus, 10.2% from colon and rectum. The most common location of leiomyomas and leiomyosarcomas was esophagus （45.5%）. The most common location of neurogenictumors was retroperitoneam （74.1%）. Common symptoms of GISTs included digestive tract hemorrhage in 36 cases （28.3%）, abdominal pain in 27 cases （21.3%） and abdominal mass in 24 cases （18.9%）. Other GIMT cases except GISTs had no first symptom of digestive tract hemorrhage. It was noticed that 79.5% of GISTs had no obvious invasion, and 72.7% of leiomyomas and leiomyosarcomas had no obvious invasion. 33.3% of neurogenic tumors invaded the adjacent organs or tissues. No metastases had been found in other GIMT cases except GISTs. The neoplastic cells of GISTs were composed of various percentage of spindle （72.5%）, epithelioid （11.8%） and mixed-type cells（15.7%）. The percentage of spindle cells in leiomyomas and leimyosarcomas was 94.The immunohistochemical results of GISTs showed that the positive rate of CDll7 was 93.7% ,CD34 was 69.3%,Desmin was 13.4%, SMA was 12.6% ,and PS100 was 10.2%. The immunohistochemical results of leiomyomas and leiomyosarcomas showed that the positive rate of Desmin was 78.5% ,SMA was 63.6% ,whileas the expressions of CDl17,CD34,and PS100 were negative. Diffuse strong positive staining of PS100 was observed in 88.9% of neurogenic tumor patients. Conclusions GISTs are the most common tumors among GIMTs. GISTs are different from neuregenic tumors, leiomyomas and leiomyosarcomas in initial symptom, tumor location, biological behavior and immunophenotype.Immunohistochemistry plays an important role in differentiating GISTs from leiomyomas and neuregenic tumors.