多房性囊性肾细胞癌的临床病理特点

Clinicopathologic features and differential diagnosis of multilocular cystic renal cell carcinoma

目的探讨多房性囊性肾细胞癌（ MCRCC）的临床病理特点及与其他肾囊性疾病的鉴别诊断。方法收集19例MCRCC的临床病理资料，并与同期诊断的其他肾囊性疾病46例（包括透明细胞肾细胞癌伴广泛囊性变12例、透明细胞乳头状肾细胞癌6例、管状囊性癌2例、单纯性囊肿22例、囊性肾瘤1例和多囊肾3例）进行形态学和免疫组织化学比较。结果19例患者中男性14例，女性5例，平均年龄50岁。临床上多因体检发现，偶有血尿或腰痛等症状。17例获随访，时间6～170个月，均未见复发和转移。病理检查：肿瘤直径1.5～7.0 cm，边界大多清楚，切面均呈多房囊性或蜂窝状，囊内含清亮液体、血液或浑浊液体，内壁光滑，不见实性区域或大体可见的壁结节。镜下观察：囊腔衬覆单层胞质透明、核小、无核仁、Fuhrman核分级Ⅰ级瘤细胞，少数（5例）为Ⅱ级，部分囊壁上皮增生为多层，个别囊内有小乳头形成。大多数病例纤维间隔内出现与囊腔衬覆细胞相似的透明细胞团，14例肌纤维母细胞增生显著。免疫组织化学染色：囊腔内衬上皮及间隔内透明细胞团对上皮性标志物广谱角蛋白、上皮细胞膜抗原和CK7均高表达，阳性比例分别为19／19、16／19和15／19；碳酸酐酶Ⅸ（ CAⅨ）和PAX8分别在17／19和15／19的病例表达；CD10、肾细胞癌标志物（ RCC ）和α-甲酰基辅酶A消旋酶较少表达，阳性比例分别为7／19、6／19和2／19；所有病例对34βE12、CD117和CD68均阴性。结论多房性、纤维间隔内核分级低的透明细胞团并肌纤维母细胞及囊壁上皮下微血管增生是MCRCC的重要形态学特征；CAⅨ、CK7阳性，CD10、RCC多阴性是MCRCC的重要免疫表型，CAⅨ有助于肾脏各种良恶性囊性病变的鉴别诊断；MCRCC是一种预后极好的低度恶性囊性肾肿瘤。

Objective To investigate the clinicopathological characteristics and the diagnosis of multilocular cystic renal cell carcinoma （ MCRCC）.Methods The clinicopathological data of 19 MCRCC cases were collected and immunohistochemical staining assays were carried out .Forty-six cases of other cystic kidney lesions within the same period were collected as controls , including extensively cystic clear cell RCC （12 cases）, clear cell tubulopapillary renal cell carcinoma （6 cases）, tubulocystic carcinoma （2 cases）, simple cortical cysts （22 cases）, multilocular cystic nephroma （1 cases） and multicystic kidney （3 cases）. Results The patients included 14 males and 5 females.The ages ranged from 31 to 66 years （ median age=50 years ）.Most of the MCRCC cases were detected incidentally in physical examination , occasionally accompanied with hematuria , back pain or other symptoms.The follow-up period of 17 patients ranged from 6 to 170 months.All patients were alive without evidence of tumor recurrence or metastasis.Pathological findings showed that macroscopically , tumor size ranges from 1.5 to 7.0 cm in the maximum diameter , generally a entirely of various sized.The cysts contain serous , hemorrhagic or turbid fluid.Solid areas or substantially discernible mural nodules were absent; histologicallly , single layer of cuboidal and flattened epithelial tumor cells were lined in the cysts , described as clear cytoplasm , small nuclear , no nucleoli and low Fuhrman nuclear grade （ I or II）.Multilayer tumor cells could be observed in a few cysts , with granular cytoplasm and small intracystic papillae formed.The clear tumor cell clusters , similar as cystic lined tumor cells, were seen within pathological fibrous in almost all cases , and significant myofibroblastic proliferation was found in 14 cases.Immunohistochemically , the cysts lined epithelial cells and the clear tumor cell clusters were positive for epithelium markers , including CKpan（19/19）, EMA（16/19） and CK7 （15/19）;higher percentage of CAⅨ（17/19）and PAX8（15/19） than control groups, but lower percentage of CD10 （7/19）, RCC （6/19） and AMACR （2/19）; and all were negative for 34βE12, CD117 and CD68.Conclusions Multilocular cysts , clear cells clusters of low Fuhrman grade within fibrous septa and capillary vessel proliferation under epithelium are important features of MCRCC.The united using of CAⅨ, CK7, CD10 and RCC is helpful for differentiating variable cystic renal tumor.MCRCC usually has an excellent prognosis, nephron sparing surgery is first recommended as a therapeutic strategy.