胃肠道外间质瘤的临床病理与生物学行为观察

目的初步探讨网膜、肠系膜、胃肠道外间质瘤(EGIST)临床病理特点,用Fletcher等推荐的GIST生物学行为评价表进行评估,探讨该标准对EGIST的适用性。方法18例网膜和肠系膜原诊断为平滑肌瘤、平滑肌肉瘤、神经鞘瘤、恶性黑色素瘤等的间叶性肿瘤,平均直经6～40cm,应用CD117、CD34、平滑肌动蛋白(SMA)、结蛋白、S100及HMB45等进行免疫组化标记。结果共诊断12例EGIST,平均直经4～35cm。其中网膜6例,肠系膜6例。肿瘤形态:梭行细胞为主型6例,上皮细胞为主型3例,混合型3例。免疫组化:所有肿瘤波形蛋白均阳性,12例CD117阳性诊断为EGIST,10例CD34阳性,阳性率为83%。12例EGIST生物学行为评价分为:低度侵袭危险性2例,中度侵袭危险性6例,高度侵袭危险性4例。12例中9例有随访资料,随访率为75%,随访时间为12～48个月,不同侵袭危险性病例各组以随访结果作出Kaplan-Meier生存曲线,用F检验进行组间生存率比较P<0.05,显示生物学行为的病理学参数与随访结果有较好的相关性。侵袭危险性低、中、高各组间生存曲线差异明显。结论CD117对EGIST有诊断价值,CD34也有一定意义。Fletcher等推荐的GIST生物学行为评价表对EGIST有较好的实用性。EGIST预后似乎GIST为好,但需要更多资料佐证。

Observation on Clinicopathologic and Biological Behavior of External Gastrointestinal Stromal Tumor

Objective To explore the clinicopathological and immunohistochemical features of external-gastrointestinal stromal tumors(EGIST) arising from omentum and mesentery.Methods Eighteen patients with mesenchymal neoplasm arising from omentum and mesentery were studied morphologically with panel of immunohistochemistry including CD117,CD34,SMA,desmin,S100 and HMB45.Results Among the 18 cases,12 were diagnozed as EGIST,and tumor size ranged from 4cm to 35cm in diameter.All EGIST expressed CD117(12/12) and 83% expressed also CD34(8/12).Conclusions Positive CD117 staining is considered to be the defining marker to differentiate EGIST from other omentum and mesentery tumors.Subclassification of GIST using Fletcher's scheme in EGIST correlates with the clinical behavior of the tumor.