摘要目的 研究血管周上皮样细胞肿瘤(PEComa)的免疫表型和分子遗传学改变及其与临床病理特征的关系.方法 收集25例PEComa患者的存档蜡块、病理及临床资料,采用免疫组织化学(SP法或EnVision法)检测相关免疫标志物,同时以多种肿瘤进行对照.运用荧光原位杂交(FISH)方法检测25例PEComa中TFE3基因的易位及扩增情况.结果 25例患者年龄21 ～61岁(平均43岁),男女比例为1∶1.3.22例为肝脏和肾脏的血管平滑肌脂肪瘤(AML),由成熟脂肪组织、梭形或上皮样平滑肌细胞和特征性的厚壁血管组成；3例为肝肾外PEComa,形态与经典AML有明显区别,肿瘤由单行性上皮样或梭形细胞构成,呈片状、巢状排列.免疫组织化学结果显示:25例PEComa组织蛋白酶K(cathepsin K)均呈强阳性(100％,25/25),HMB 45、Melan A和平滑肌肌动蛋白(SMA)的阳性率分别为80％ (20/25)、88％ (22/25)和88％(22/25),阳性瘤细胞占所有瘤细胞的百分比平均值:cathepsin K为90％、HMB 45为36％、Melan A为41％、SMA为35％.TFE3在肝肾AML中全部阴性(22/22),而在肝肾外PEComa中均为阳性(3/3).经FISH证实25例PEComa均不存在TFE3基因融合或扩增.结论 肝肾外PEComa的组织学形态与经典AML有明显区别,其发病与TFE3蛋白高表达关系密切,可能为独立的PEComa分子亚型.cathepsin K在PEComa中阳性率高,敏感性优于HMB 45、Melan A和SMA,可用于PEComa与其他常见的多种肿瘤的鉴别诊断.

abstractsObjective To study the clinicopathologic features,immunophenotype and genetic changes of perivascular epithelioid cell neoplasms (PEComa).Methods A total of 25 cases of PEComa located in various anatomic sites were selected for immunohistochemical staining (SP or EnVision method).TFE3 fluorescence in-situ hybridization was also performed to determine the TFE3 gene status.Results The age of patient ranged from 21 to 61 years (mean =43 years).The male-to-female ratio was 1∶1.3.Histologically,22 cases represented conventional angiomyolipomas,composed of a mixture of adipose tissue,spindle element,epithelioid smooth muscle cells and abnormal thick-walled blood vessels in various proportions.Three cases involving lung,soft tissue and broad ligament had subtle but distinctive morphologic features.Nested or sheet-like architecture with epithelioid or spindle cells was observed.Immunohistochemical study showed that HMB 45,melan A,smooth muscle actin and cathepsin K were expressed in 80％ (20/25),88％ (22/25),88％ (22/25) and 100％ (25/25) of PEComa,respectively.Within positive cases,the average proportion of positive tumor cells was 36％,41％,35％and 90％ respectively for HMB 45,melan A,smooth muscle actin and cathepsin K.TFE3 was negative in all of the 22 renal and hepatic PEComa studied,while it was positive in the 3 cases of extra-hepatorenal PEComa.None of the 25 cases exhibited evidence of TFE3 gene fusion or amplification.Conclusions Extra-hepatorenal PEComa have distinctive morphologic features and are associated with TFE3 overexpression.Cathepsin K immunostaining demonstrates high sensitivity and specificity in PEComa,better than other commonly employed immunomarkers.This marker is thus useful in diagnosis of PEComa and distinction with other neoplasms.