泌尿系统血管周上皮样细胞肿瘤临床病理学分析

Perivascular epithelioid cell tumor of urinary system： a clinicopathologic analysis of 21 cases

目的探讨泌尿系统血管周上皮样细胞肿瘤（PEComa）的临床病理学特征、诊断及鉴别诊断。方法复习北京大学人民医院2002年9月至2010年9月诊治的泌尿系统的PEComa21例标本，观察其组织病理学形态，行免疫组织化学EnVision法染色，并复习相关文献。结果21例患者平均发病年龄51．3岁（范围16～76岁），男性5例，女性16例，男女比1：3．2。20例为肾脏血管平滑肌脂肪瘤（AML），其中经典型10例，上皮样型5例，平滑肌瘤型3例，硬化型1例，炎症型1例；1例为膀胱PEComa。免疫组织化学染色显示：HMB45和平滑肌肌动蛋白（SMA）阳性率分别为95．2％（20／21）和80．9％（17／21），Melan A阳性率为71．4％（15／21），结蛋白阳性率为61．9％（13／21），S-100蛋白阳性率为33．3％（7／21），Ki-67平均阳性指数1．29％（范围0～5％）。其中5例上皮样型AML对HMB45和Melan A均呈阳性表达，SMA和结蛋白的表达率均为1／5，与非上皮样型AML肿瘤表达有所不同，但差异无统计学意义（P〉0．05）。1例膀胱PEComa仅显示HMB45和SMA阳性。结论泌尿系统PEComa以。肾的AML最为多见，而肾上皮样型AML和膀胱PEComa较为少见，具有较独特的病理学特征，需与其他恶性病变相鉴别，免疫组织化学染色标记HMB45、MelanA和SMA对于泌尿系统PEComa的诊断具有帮助。

Objective To study the clinicopathologic features and differential diagnosis of perivascular epithelioid cell tumors （PEComas） occurring in the urinary system. Methods The clinicopathologic features of 21 cases of PEComa from September 2002 to September 2010 occurring in the urinary system were retrospectively reviewed. Immunohistochemical study for HMB 45, S-100 protein, smooth muscle actin, desmin, Melan A and Ki-67 was carried out. Results Amongst the 21 cases studied, there were 5 males and 16 females. The age of patients ranged from 16 to 76 years （median = 51.3 years） Twenty cases occurred in the kidney and 1 in the bladder. The predominant histopathologic subtype of renal PEComas was classic type （10/20）, followed by epithelioid type （5/20）, smooth muscle type （3/20）, inflammatory type （1/20） and sclerosing type （1/20）. Immunohistochemical study showed that HMB 45 and smooth muscle actin were positive in 95.2% （20/21） and 80. 9% （17/21） cases, respectively. Melan A, desmin and S-100 protein were expressed in 71.4% （ 15/21 ）, 61.9% （ 13/21 ） and 33.3% （7/21） cases, respectively. The mean proliferative index was 1.29% （range -- 0 to 5% ）. HMB 45 and Melan A were expressed in all of the 5 cases of epithelioid PEComas, whereas smooth muscle actin and desmin were only expressed in one of them. There was no significant difference between epithelioid PEComas and non-epithelioid PEComas in the expression of HMB 45, Melan A, smooth muscle actin and desmin. Positive staining for HMB 45 and smooth muscle actin was demonstrated in the case of bladder PEComa. Conclusions PEComas of the urinary system predominantly affect the kidney. Eplthelioid renal PEComas and bladder PEComa are relatively rare and have unique pathologic features. It is necessary to distinguish PEComas from other malignant tumors. Immunohistochemical study for HMB 45, Melan A and smooth muscle actin is helpful for confirmation of diagnosis.