目的:总结在儿童Xp11.2易位/TFE3基因融合相关性肾细胞癌(Xp11 RCC)诊断过程中可能遇到的问题，提高对本病的认识及诊断水平。方法:收集2015年1月至2019年12月首都儿科研究所附属儿童医院经病理确诊的5例Xp11 RCC患儿的临床及病理资料，并进行回顾性分析。结果:5例患儿中男2例，女3例，年龄4～8岁，均以发现腹部包块就诊，入院完善检查后，4例行肾脏及肿瘤根治性切除术，1例行肿物单纯切除术，术后病理行常规HE染色、免疫组织化学染色及荧光原位杂交(FISH)检测。肿瘤组织学形态多样，呈巢片状、腺泡状或乳头状排列，胞质丰富，从完全透明到粉染嗜酸性，可见砂砾样钙化；其中1例肿瘤细胞除经典的排列方式外，还可见部分区域呈微乳头状排列；1例瘤细胞胞质丰富，呈强嗜酸性，并可见细胞内含圆形或椭圆形的嗜酸性小体。5例瘤细胞均呈核弥漫性强表达TFE3，FISH检测均存在异常分离信号。结论:Xp11 RCC是一种较少见的肾脏恶性肿瘤，组织学形态多样，应与儿童常见的肾脏肿瘤相鉴别，其免疫组织化学表达及分子检测均较特异，可结合临床发病情况进行诊断。“,”Objective:To summary the problems that may be encountered in the diagnosis of Xp11.2 translocation/TFE3 gene fusion associated renal cell carcinomas (Xp11 RCC) and to improve the understanding and diagnostic level.Methods:The clinical and pathological data of 5 children with Xp11 RCC pathologically diagnosed in Children′s Hospital of Capital Institute of Pediatrics from January 2015 to December 2019 were collected for retrospective analysis.Results:The 5 cases included 2 males and 3 females with the age of 4-8 years old.All cases presented with abdominal mass.Four cases received radical nephrectomy and radical tumor resection, and 1 case received simple tumor resection after related examination.Routine HE staining, immunohistochemical staining and fluorescence in situ hybridi-zation (FISH) were performed after surgery.The histological morphology of tumor was varied, and the tumor cells were arranged in nest flake, acinar or papillary pattern, with abundant cytoplasm form completely transparent to eosinophilic staining (pink), and gravel-like calcification was visible.Micropapillary arranged tumor cells appeared in 1 case besides classic pattern; in another case, the tumor cells were highly eosinophilic with abundant cytoplasm and visible round or elliptic eosinophilic bodies.The tumor cells in 5 cases showed diffuse and strong expression of TFE3, and FISH assay showed abnormal separation signal.Conclusions:Xp11 RCC is a relatively rare renal malignant tumor with diverse histological morphology, which should be distinguished from other common renal tumors in children.Its immunohistochemical expression and molecular detection are of specificity, and it should be diagnosed based on clinical incidence.