色素微囊性嫌色细胞肾细胞癌五例临床病理学特征

Pigmented microcystic chromophobe renal cell carcinoma:a clinicopathologic analysis of five cases

目的探讨色素微囊性嫌色细胞肾细胞癌(chRCC)的临床病理特征及其诊断和鉴别诊断。方法收集2013年1月至2018年1月浙江省人民医院杭州医学院附属人民医院5例色素微囊性chRCC,观察其临床特征、大体和组织学表现、免疫表型特点以及预后并结合文献进行复习。结果3例男性,2例女性;年龄45~72岁(平均57岁)。均为影像学检测偶然发现。肿瘤直径1.8~4.0cm(平均2.9cm),界限清楚;切面灰棕灰褐,实性为主夹杂有大小不等的囊性扩张,常见出血,未见中央瘢痕形成。镜下5例肿瘤均以大小不等和形状不规则的微囊性囊肿和管囊状成分为主,1例可见广泛的筛状结构,1例可见局灶的腺瘤样排列,2例局灶可见无纤维血管轴心的假乳头状结构。间质内均可见营养不良性钙化或沙砾体形成。4例以嗜酸性瘤细胞为主,1例以浅染的植物样细胞为主。5例均可见散在的细胞内外棕色色素沉积;瘤细胞核型不规则,核级别低(Paner分级1级),常见双核和核周空晕。均未见坏死和肉瘤样转化。免疫组织化学染色:5例均弥漫强表达细胞角蛋白(CK)、上皮细胞膜抗原(EMA)和E-cadherin,4例弥漫表达CK7和CD117。均不表达波形蛋白、CD10、碳酸酐酶Ⅸ、AMACR/P504s、TFE3、HMB45、Melan A、S-100蛋白、突触素、嗜铬粒素A等。5例均行部分肾切除术,随访2-55个月(平均17个月)均未见肿瘤复发和转移。结论色素微囊性ChRCC是一种少见的ChRCC组织学亚型,生物学行为惰性,形态学上存在异质性,鉴别诊断谱系宽广,仔细的形态学观察寻找典型的ChRCC特点并辅以免疫组织化学染色可助于其诊断和鉴别诊断。

Objective To investigate the clinicopathologic features, diagnostic and differential diagnostic aspects of pigmented microcystic chromophobe renal cell carcinoma ( ChRCC). Methods Five cases of pigmented microcystic ChRCC were collected at Zhejiang Provincial People's Hospital from January 2013 to January 2018. The clinical features,gross and histological appearances,immunohistochemistry and prognosis were analyzed and the relevant literature was reviewed. Results There were 3 men and 2 women with age range of 45 years to 72 years (mean 57 years). All tumors were incidentally identified by imaging examinations. Grossly, the tumors were well-demarcated and showed diameters ranging from 1. 8 cm to 4. 0 cm(mean 2. 9 cm). On cross section,the tumors were brown to gray tan with solid cut-surface mixed with multiple cysts of variable sizes. Hemorrhage was common,central scar was not seen. Microscopically, the tumors were composed predominantly of irregular and variable-sized microcystic or tubulocystic patterns, with extensive cribriform structures formation and focal adenomatous rearrangements seen in one case each, and focal pseudo-papillary structures ( lacking true fibro-vascular cores) seen in two cases. Microscopic calcifications and psammoma bodies were present in all tumors. Four tumors composed mostly of eosinophilic cells whereas 1 predominated in plant-like cells. Brown pigmentations, either intracytoplasmic or extracytoplasmic,were noted in all five cases. The tumor cells had irregular,low-grade nuclei (Paner grade:1) frequently with binucleation and perinuclar halos. Tumor necrosis or sarcomatous transformation was not seen. By immunohistochemistry,the tumor cells expressed CK,EMA,and E-cadherin diffusely and strongly in five cases; and CK7 and CD117 diffusely in four cases. They were negative for vimentin,CD10,CA9, AMACR/P504s, TFE3, HMB45, Melan A, S-100 protein, synaptophysin and chromogranin. Partial nephrectomies were performed for all five patients; there was no tumor recurrences or metastases at a follow-up of 2 to 55 months (mean,17 months). Conclusions Pigmented microcystic ChRCC is a rare histological variant of ChRCC with relatively indolent behavior,and shows morphologic heterogeneity which can elicit a wide range of differential diagnoses. Careful attentions to search for typical features of classic ChRCC with the use of immunohistochemistry can help to distinguish this tumor from its many mimickers.