先天性中胚层肾瘤临床病理和分子遗传学分析

Congenital mesoblastic nephroma: clinicopathological features and molecular genetic analyses

目的探讨先天性中胚层肾瘤(congenital mesoblastic nephroma,CMN)的临床病理特征和分子遗传学改变。方法回顾性分析9例CMN,总结其组织病理形态、免疫组化标记及ETV6基因易位FISH检测结果。结果 9例CMN均为2岁以内的患儿,其中8例小于1岁。肿瘤平均直径9.5 cm(3.2~15.0 cm)。经典型3例,细胞型5例,混合型1例;其中5例可见囊性变,2例可见软骨岛。与经典型相比,细胞型CMN的肿瘤直径常更大,易出现出血、坏死,核分裂象更多见。免疫表型:肿瘤细胞表达vimentin,余未见特异性阳性标记,且均不表达WT-1。其中5例(4例细胞型和1例混合型)行ETV6基因易位FISH检测,3例细胞型CMN检出ETV6基因易位,1例细胞型和1例混合型CMN未检出ETV6基因易位。2例失访,7例随访5~46个月,均未见复发。结论 CMN为少见的婴幼儿肾脏肿瘤,具有独特的临床病理学特征,细胞型CMN有特异的ETV6基因易位。CMN多预后良好,需与其它儿童肾恶性肿瘤鉴别。

Purpose To discuss clinicopathological features and molecular genetic change of congenital mesoblastic nephroma （CMN）. Methods Nine cases diagnosed as CMN were analyzed retrospectively in this study. Histological features, immunohistochemical profiles and ETV6 gene rearrangement status were assessed. Results All patients were within two years of age and eight of them were within one year. The average diameter of tumors was 9.5 cm （3.2 - 15.0 cm）. These series cases included 3. classic CMN, 5 cellular CMN and 1 mixed CMN. Cystic degeneration was found in 5 cases, and cartilage islands were observed in 2 cases. Compared with classic CMN, tumor size was bigger, and hemorrhage, necrosis and mitotic figures were easily to see in cellular CMN. All the tumor cells were positive for vimentin and negative for WT-1 by immunohistochemistry. ETV6 gene rearrangement was detected in 5 cases （including 4 cellular CMN and 1 classic CMN ）. Three cellular CMN harbored ETV6 gene translocation, 1 mixed CMN and 1 cellular CMN were negative for ETV6 gene translocation by FISH analysis. The follow up data were obtained in 7 cases and 2 cases were lost. All the 7 patients were alive without evidence of recurrence and metastasis from 5 to 46 months. Conclusion CMN is a rare infant renal tumor with unique clinicopathological characteristics. Most of cellular CMNs harbor ETV6 gene translocation. The prognosis of CMN is relative good and needs to be differentiated from other malignant renal tumors.