肾嗜酸细胞腺瘤10例临床病理分析

Renal oncocytoma:a clinicopathologic study of 10 cases

目的探讨肾嗜酸细胞腺瘤的临床病理特点、免疫表型及鉴别诊断。方法分析10例RO的临床表现、影像学、组织学和免疫表型特点,并复习相关文献。结果 10例肾嗜酸细胞腺瘤中男性4例,女性6例,年龄44～78岁,平均57.8岁。病变位于左肾6例,右肾4例。大体见瘤组织边界清楚,切面均质、棕红色或褐色,3例瘤中心可见纤维性瘢痕。镜下,肿瘤由形态一致的小圆形细胞组成,呈巢团、腺泡状或致密片状排列,间质常可见特征性的疏松水肿的纤维结缔组织。瘤细胞胞质丰富,嗜酸性,核呈小圆形、规则,偶见局灶性核异型,但无核分裂象或罕见。免疫组化示10例CK18和E-cadherin均(+),9例EMA(+),CD117、CD10和CK7不同程度(+),CKpan和RCC各有1例(+);而vimentin、34βE12、HMB45和S-100均(-),Ki-67均<1%。结论肾嗜酸细胞腺瘤是一种少见的良性肾上皮性肿瘤。巢团状排列的瘤细胞分布于细胞稀少、疏松水肿的纤维结缔组织中是肾嗜酸细胞腺瘤最重要的形态学特征。免疫组化瘤细胞EMA、CD117和E-cadherin(+),vimentin、CK7和CD10(-),有助于与其他肾肿瘤鉴别。

Objective To study the clinicopathological features,immunophenotype and differential diagnoses of renal oncocytoma.Methods Clinical manifestations,radiological,histological characteristics and immunophenotypes were analyzed in 10 cases of renal oncocytoma.Results 4 male and 6 female patients,with ages ranging from 44 to 78 years（mean 57.8 years）,and six cases located on the right side and four on the left side.Multifocal disease was noted in 1 case.Grossly,the tumors were all well circumscribed with brown to tan cut surface and sized 1 to 10 cm in diameter.Central fibrous scar was noted in three cases.Histologically,the tumor cells were mainly arranged in closely packed nests,acini or tubules and occasionally microcystic pattern in loosely edematous and fibrous stroma.Tumor cells had moderate to abundant granular eosinophilic cytoplasm with a small,round and uniform nucleus containing finely and evenly dispersed chromatin,but focal nuclear atypia was also seen.Mitotic figure was absent or rare.Immunohistochemically,all cases were diffusely positive for CK18 and E-cadherin,and showed variable immunoreactivity for CD117,CD10 and CK7,of which 9 cases were positive for EMA.But all cases were negative for vimentin,34βE12,HMB45 and S-100.The proliferating index（Ki-67） was very low in all cases,with less than 1% of the nuclei labeled Conclusions Renal oncocytoma is a rare benign tumor of the kidney with excellent outcomes.That the tumor cells arrange in nests or acini architectural pattern with loosely hypocellular and edematous stroma is the most important histological feature.