[Clinicopathological features of mature T/NK cell lymphoma with aberrant CD20 or CD79α expression].

Objective: To investigate the clinicopathological characteristics and prognosis of mature T/NK cell lymphomas with aberrant CD20 or CD79α expression. Methods: A retrospective analysis of 641 cases of mature T/NK cell lymphoma diagnosed from January 2014 to December 2020 was performed, and 14 cases of CD20-positive and one case of CD79α-positive mature T/NK-cell lymphoma were identified. Histological examination, immunohistochemical characterization, in situ hybridization for Epstein-Barr virus encoded early RNA (EBER), and PCR testing for immunoglobulin and T cell receptor (TCR) gene rearrangements were performed. Clinicopathological characteristics of these lymphomas were analyzed. Results: There were 13 males and 2 females, with a median age of 56 years. There were 8 cases of peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), 3 cases of extranodal NK/T-cell lymphoma, nasal type (ENKTCL), 2 cases of monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) and 2 cases of angioimmunoblastic T-cell lymphoma (AITL). Twelve cases were stage Ⅲ or Ⅳ lymphomas. The prognosis was overall poor. The histology, immunophenotype and TCR gene rearrangement were not significantly different from the corresponding types of lymphoma. Ki-67 proliferation index was over 70% in all cases. The expression of CD20 or CD79α was weak and heterogeneous. All 15 case of Ig gene rearrangement were polyclonal. Conclusions: Mature T/NK cell lymphoma with abnormal expression of CD20 or CD79α is rare, commonly found in advanced stage, and associated with poor prognosis. The expression of CD20 or CD79α in these cases is weaker than the corresponding mature T/NK cell lymphomas, while its proliferation index is higher. Histomorphology, extensive immunoprofiling and molecular detection are required for accurate diagnosis.目的： 探讨CD20或CD79α异常表达的成熟T/NK细胞淋巴瘤临床病理学特征及预后。 方法： 回顾性分析河南省人民医院2014年1月至2020年12月诊断的641例成熟T/NK细胞淋巴瘤，筛选14例CD20阳性和1例CD79α阳性的成熟T/NK细胞淋巴瘤，收集临床资料，采用HE、免疫组织化学染色和EB病毒编码的RNA（EBER）原位杂交及免疫球蛋白（Ig）、T细胞受体（TCR）基因重排检测，并分析临床病理特征。 结果： 男性13例，女性2例，中位年龄56岁。8例非特指外周T细胞淋巴瘤（PTCL-NOS）、3例结外NK/T细胞淋巴瘤（ENKTCL）、2例单形性嗜上皮性肠道T细胞淋巴瘤（MEITL）及2例血管免疫母细胞性T细胞淋巴瘤（AITL）。12例属于Ⅲ/Ⅳ期，预后差。组织学形态、免疫表型及TCR基因重排与相对应的淋巴瘤类型无明显差异。Ki-67阳性指数均>70%。CD20或CD79α表达弱且具有异质性。15例Ig基因重排均呈多克隆。 结论： CD20或CD79α异常表达的成熟T/NK细胞淋巴瘤少见，分期晚，预后差。CD20或CD79α表达弱，增殖指数高。其诊断应结合组织学观察、多种抗体联用及基因重排等多种检测。.