265例胃肠道间叶源性肿瘤的临床病理特征及超声内镜诊断价值

目的探讨胃肠道间叶源性肿瘤（gastrointestinal mesenchymal tumor,GIMT）的临床病理特征及超声内镜（edoscopic ultrasonography,EUS）的诊断价值.方法观察265例GIMT病理特征并检测CD117、CD34、平滑肌肌动蛋白（SMA）、S-100、Ki-67等抗体的表达情况,确诊后回顾其中32例术前EUS检查结果.结果 265例GIMT中胃肠道间质瘤（gastrointestinal stromal tumor,GIST）146例,平滑肌（肉）瘤（leiomyoma or leiomyosarcoma）113例,神经源性肿瘤6例.免疫组化结果：GIST以CD117阳性132/146（90.4%）和CD34阳性109/146（74.7%）为主,SMA和S-100分别在平滑肌（肉）瘤和神经鞘膜瘤中强阳性表达,9例GIST中7例Ki-67阳性且伴较多有丝分裂,病理诊断为交界性或恶性GIST.交界性、恶性GIST多见于男性患者.EUS对GIST、平滑肌瘤的定位准确率为96.9%,诊断准确率84.4%,良恶性鉴别准确率71.9%.结论 GIMT主要为GIST.形态上类似的GIST与平滑肌瘤及神经鞘膜瘤区别可用CD117、CD34、SMA、S-100等多种免疫组化标记物.联用Ki-67表达和有丝分裂数判断间质瘤的良恶性的敏感性、特异性高.EUS对于GIMT的诊断及良恶性鉴别有一定的应用价值,结合EUS引导下细针穿刺（EUS-FNA）活检是未来的诊断选择.

The clinicopathologic characteristics of gastrointestinal mesenchymal tumor and the diagnostic value of endoscopic ultrasonography

Objective To investigate the clinicopathologic characteristics of gastrointestinal mesenchymal tumor (GIMT), and to determine the diagnostic value of endoscopic ultrasonography (EUS) for it. Methods The morphologic characteristics of GIMT were observed by light microscopy in 265 cases. The expression of CD117, CD34, smooth muscle actin (SMA) , S-100 and Ki-67 were detected by Envision immunohistochemical method. EUS results were retrospectively analyzed in 32 cases. Results Among 265 GIMT cases, there were 146 cases of gastrointestinal stromal tumor (GIST) , 113 cases of leiomyoma or leiomyosarcoma, 6 cases of neurogenic tumour. In GIST, CD117 diffuse strong expression was found in 132 of 146 (90. 4%) cases, and CD34 predominant strong expression in 109 of 146 (74. 7%). SMA and S-100 expressions were found in mesenterium (retroperitoneum) and neurogenic tumour respectively. Expression of Ki-67 with significant karyokinesis was found in 7 of 9 cases with borderline or malignant profiles in histology. Most borderline and malignant tumors were found in male. The accuracies of EUS for determination of GIST location, the diagnosis of GIST and differentiation of benign from malignant were 96. 9% , 84. 4% and 71.9% respectively. Conclusions GIST rather than leiomyomas are the most common GIMT. Immunohistochemical markers such as CD117, CD34 and SMA, S -100 can differentiate GIST from leiomyomas and neurogenic tumors. The expression of Ki-67 with significant karyokinesis supports the diagnosis of malignant tumor. EUS plays an important role in detecting GIMT and in differentiating benign from malignant. Endoscopic ultrasound-guided fine-needle aspiration biopsy may be the better diagnostic choice in the future.