摘要目的:探讨具有TSC2基因突变的儿童嗜酸性实性和囊性肾细胞癌（ESC RCC）临床病理特征、免疫组织化学及分子遗传学特征和预后。方法:收集2017年至2018年2例ESC RCC临床资料，HE和免疫组织化学染色（EnVision）法进行形态学观察；荧光原位杂交检测TFE3、TFEB断裂重排基因；分子基因检测，PCR扩增，二代测序。结果:2例ESC RCC为男性，年龄分别9岁8个月和13岁，均发生在右肾。肿瘤大小5~7 cm，切面囊实性，灰红、灰白鱼肉样。显微镜下肿瘤具有纤维性包膜，肿瘤细胞突破胞膜。肿瘤细胞弥漫分布，圆形、多边性，胞质丰富，嗜伊红，可见大小不一的空泡，呈透明细胞样；部分区域类似乳头样结构，可见纤维轴心。细胞核圆形、泡状核，易见多核及巨核细胞，核分裂象未见；少量大小不一的囊样结构，囊壁可见单层瘤细胞被覆呈钉突样。间质见厚壁血管，灶状淋巴细胞浸润；较多嗜伊红坏死，可见钙化和胆固醇结晶。免疫组织化学阳性表达：PAX8（弥漫）、细胞角蛋白（CK）20、广谱细胞角蛋白（CKpan，局灶）、CD10（1例局灶/1例弥漫）、INI1、波形蛋白、CD68阳性，Ki-67阳性指数5%~10%。HMB45、S-100蛋白、Melan A、p53、结蛋白、TFE3、CK7、CK19、上皮细胞膜抗原（EMA）、CD56、嗜铬粒素A（CgA）、突触素、CD30、CD117、WT1、平滑肌肌动蛋白（SMA）阴性。分子遗传学检测：TFE3、TFEB断裂重排阴性。二代测序：例1，TSC2 p.Lys574Ter（0.198）；例2，TSC2 p.Arg406Ter（0.355）。结论:ESC RCC儿童发病比较罕见，容易误诊，其具有独特的病理形态学特征、免疫表型和分子遗传学改变，预后较好。

abstractsObjective:To study clinical pathological characteristics, immunohistochemical, molecular genetical changes and prognosis in pediatric eosinophilic solid and cystic renal cell carcinoma (ESC RCC) with TSC2 gene mutations.Methods:The tissue samples were collected from two pediatric ESC RCC patients between 2017 and 2018. The tissues were subjected to histological examination and immunohistochemistry using EnVision system. The TFE3, TFEB gene rearrangements were tested using FISH and molecular genetic study. The paraffin sections were used for DNA extraction, PCR amplification and NGS sequencing.Results:The two patients with ESC RCC were both male, aged at 9 years and 8 months, and 13 years, respectively. The tumors were from the right kidney, 5 cm and 7 cm in size, respectively, with solid and cystic changes in cross section, and grey-reddish or grey-whitish fish meat appearance. Microscopic observation revealed the tumors had fibrous capsules, which were infiltrated by the tumor cells. The tumor cells were diffusely distributed, round-shaped, or polygon-shaped, and had voluminous cytoplasm, eosinophilic cytoplasm, various sizes of vacuoles and clear cell-like appearance. There were papillary structures in some areas, with visible fiber septa. The nuclei were round and vesicular, with multi-nucleated cells and megakaryocytes. The mitoses were not seen. A few cystic structures were visible in different sizes, and capsule walls were covered with a single layer of spike-like tumor cells. Thick-walled blood vessels were seen in the stroma, with focal lymphocytic infiltration, eosinophilic necrosis, calcifications and cholesterol crystals. Immunohistochemistry of the tumor cells was positive for PAX8 (diffuse), CK20 (focal), CKpan (focal), CK10 (1 focal, 1 diffuse), INI1, vimentin, CD68, and Ki-67 (5%~10%); the tumor cells were negative for HMB45, S-100, Melan A, p53, desmin, TFE3, CK7, CK19, EMA, CD56, CgA, Syn, CD30, CD117, WT1 and SMA. Molecular genetic study showed that TFE3 and TFEB gene rearrangements were not detected by FISH. NGS sequencing showed TSC2 p.Lys574Ter (0.198) was found in patient one and TSC2 p.Arg406Ter (0.355) in patient two.Conclusions:ESC RCC in children is a rare disease, and can be misdiagnosed easily. It has unique pathological characteristics, and immunohistochemical, molecular and genetic changes. The prognosis is relatively good.