摘要目的探讨具有BCOR-CCNB3融合基因的尤文样未分化肉瘤（ BCOR-CCNB3肉瘤）的临床病理特征、免疫表型、鉴别诊断及预后。方法收集2006年1月至2015年12月病理诊断为Ewing／PNET肉瘤或尤文样肉瘤260例，其中17例尤文样肉瘤采用CCNB3免疫组织化学、逆转录聚合酶链反应（ RT-PCR）检测BCOR-CCNB3融合基因，3例为BCOR-CCNB3肉瘤，另选取12例尤文肉瘤作为对照，进行随访并复习相关文献。结果 RT-PCR及测序结果显示3例均携带BCOR-CCNB3融合基因。3例BCOR-CCNB3肉瘤中，女性1例，男性2例；患者年龄8～11岁。随访时间12～56个月，2例1年内死亡，1例复发。 BCOR-CCNB3肉瘤肿瘤细胞圆形、短梭形，呈实性片状排列，染色质细，核仁不明显；有纤细的毛细血管结构分隔肿瘤细胞，与肾脏透明细胞肉瘤形态相近。 CCNB3、TLE1、cyclin D1均呈弥漫的细胞核阳性（3／3）。在12例尤文肉瘤中，CCNB3均为阴性（0／12），1例（1／12）TLE1弱阳性，4例（4／12）cyclin D1阳性。结论 BCOR-CCNB3肉瘤具有独特的形态、免疫表型和临床特点，是一种独立的肿瘤类型，需要与Ewing／PNET肉瘤进行鉴别诊断，CCNB3阳性是该类型肿瘤较为特异的标志，TLE1和cyclin D1阳性也提示该肿瘤的可能，确诊需要检测BCOR-CCNB3融合基因。

abstractsObjective To investigate the morphologic , immunohistochemical , genetic, clinical features and prognosis of Ewing-like BCOR-CCNB3 gene fusion undifferentiated sarcoma ( BCOR-CCNB3 fusion sarcoma ).Method Seventeen Ewing-like sarcoma cases were screened for CCNB 3 expression and BCOR-CCNB3 fusion transcripts by immunohistochemistry and RT-PCR among 260 cases of Ewing-like sarcomas collected during Jan ,2006 to Dec,2015.Three cases of BCOR-CCNB3 fusion sarcoma were found among 17 atypical Ewing sarcomas , and follow-up were conducted.Results The harboring of BCOR-CCNB3 fusion transcript was confirmed by RT-PCR and directly sequencing results.The three patients aged between 8 and 11 years old.Two of them were male and the other one was female.One patient achieved a complete response after chemotherapy , the other two died without chemotherapy after surgical excision in 12 months.Tumor cells in all 3 cases showed diffuse nuclear CCNB3, TLE1 and cyclin D1 positivity, while CCNB3 (0/12), TLE1 (1/12) and cyclin D1 (4/12) positivity was infrequent in the 12 cases of classical Ewing′s sarcoma.The oval or plump spindle tumor cells with fine chromatin arranged in solid pattern , the nucleoli was inconspicuous.The delicate capillary networks were obvious in the tumor.Conclusion With a detailed description of the histological spectrum ,immunohistochemical features and clinical characteristic of BCOR-CCNB3 sarcoma, justify distinction from Ewing sarcoma could be possible.