伴IRF4重排的大B细胞淋巴瘤的临床病理特征及预后分析

Clinical and pathological characteristics and prognostic analysis of large B-cell lymphoma with IRF4 rearrangement

目的 探讨伴IRF4重排的大B细胞淋巴瘤(large B-cell lymphoma with IRF4 rearrangement, LBCL-IRF4r)的临床病理学特征、诊断和鉴别诊断。方法 收集8例LBCL-IRF4r临床资料,采用HE染色、免疫组化EnVision两步法、原位杂交和FISH法进行检测,观察组织学、免疫表型和分子遗传学特征,并结合相关文献进行复习。结果 8例LBCL-IRF4r中,男女比为1.67∶1,年龄10~53岁,平均25.8岁,其中发生于扁桃体5例,鼻咽2例,左腹股沟淋巴结1例。镜下肿瘤呈滤泡、弥漫或滤泡和弥漫混合的生长模式,肿瘤细胞为典型的中心母细胞或中等至大的母细胞样细胞,具有细腻的染色质和不明显的核仁,核分裂象、凋亡小体易见,未见星空现象。免疫表型:8例LBCL-IRF4r的肿瘤细胞均弥漫强表达CD20(8/8)、PAX5(2/2)、CD79a(3/3)、BCL6(8/8)和MUM-1(8/8),表达CD10(7/8)、BCL2(5/8)和CD5(4/8),不表达Cyclin D1、CD23、CD30,Ki67增殖指数70%~95%。EBER原位杂交均阴性。FISH检测8例均有IRF4基因分离(8/8),部分病例有BCL6基因分离(1/2),未检出MYC(0/4)和BCL2(0/3)基因分离。结论 LBCL-IRF4r好发于儿童和青少年,弥漫性强表达MUM-1,具有特征性IG∷IRF4基因重排,预后好,需与其它类型的大B细胞淋巴瘤鉴别。

Purpose To explore the clinicopathological features,diagnosis and differential diagnosis of large B-cell lymphoma with IRF4 rearrangement(LBCL-IRF4r).Methods Clinical data of 8 cases of LBCL-IRF4r were collect,hematoxylin-eosin and immunohistochemical of EnVision two-step stains,in situ hybridization and FISH was used to study the histology,immunotypes and molecular genetic characteristics.The relevant literatures were reviewed.Results Among 8 cases of LBCL-IRF4r,the male to female ratio was 1.67∶1,with age range 10-53 years(mean 25.8 years).Five cases occurred in tonsils,2 cases in nasopharynx and 1 cases in inguinal lymph node.Microscopically,the tumors presented with a purely follicular,purely diffuse or a combined follicular and diffuse architecture.The tumor cells were typical centroblasts and less frequently medium-sized blastic cells with smaller nucleoli,apoptosis and nuclear fragmentation were easily seen.Immunophenotypically,the tumor cells of the eight cases of LBCL-IRF4r diffuse strongly expressed CD20(8/8),PAX5(2/2),CD79a(3/3),BCL6(8/8)and MUM-1(8/8),mostly expressed CD10(7/8),partially expressed BCL2(5/8)and CD5(4/8),and did not express Cyclin D1,CD23 and CD30.The percentage of Ki67 index ranged from 70%to 95%.EBER in situ hybridization was negative in all cases.IRF4 rearrangements were detected in all cases(8/8).BCL6 rearrangements were detected in one case(1/2).MYC(0/4)and BCL2(0/3)rearrangements were not detected in all cases.Conclusion LBCL-IRF4r is more common in children and adolescents with characteristic IG∷IRF4 rearrangement and a good prognosis,which needs to be differentiated from other types of large B-cell lymphoma.