Objective: To investigate the clinicopathological characteristics of the T cell lymphomas with CD20 expression, and to better understand this rare entity. Methods: Two-hundred cases of T-cell lymphoma diagnosed in the Department of Pathology of the Affiliated Hospital of Qingdao University from November 2016 to February 2020 were examined, and 5 cases of CD20-positive T-cell lymphomas were identified and included. Combined with clinical data and review of the literature, the clinicopathological characteristics of the disease were analyzed. Results: The five patients were all male, and had an average age of 56 years (range, 47 to 64 years). There were 2 cases of monomorphic epitheliotropic intestinal T-cell lymphoma, 2 cases of mycosis fungoides (1 case was plaque stage and the other was tumor stage) and 1 case of indolent T-cell lymphoproliferative disorder of the gastrointestinal tract. Immunohistochemistry showed that all 5 cases expressed multiple T cell markers (CD3/CD4/CD5/CD7/CD8) and only one of B cell markers (CD20). Three of the 5 cases were negative for CD20 at the first diagnosis, while CD20 was diffusely positive on the second biopsy from the recurrence or progression of the disease, without expression of CD79a or PAX5. Epstein-Barr encoding region (EBER) in situ hybridization was negative in all 5 cases. T-cell receptor gene analysis showed monoclonal rearrangement of β or/and δ chains;Ig rearrangements were all polyclonal. None of the five patients were treated with rituximab, and 4 patients survived with disease and 1 patient survived without disease at the end of follow-up. Among them, the patient with mycosis fungoides at the cancerous stage has progressed rapidly and had poor quality of life. Conclusions: CD20-positive T-cell lymphoma is extremely rare. Its prognosis is closely related to the type of T-cell lymphoma, clinical stage and initial therapeutic effect. However, the expression of CD20 indicates the recurrence or progression of the disease, and the prognosis is relatively poor. When CD3 expression is absent in T-cell lymphoma, it is easy to be misdiagnosed as B-cell lymphoma. The combination of multiple immunohistochemical antibodies and molecular detection can improve the accuracy of diagnosis.
目的： 探讨CD20阳性T细胞淋巴瘤的临床病理学特征，加深对该少见疾病的认识。 方法： 回顾性分析2016年11月至2020年2月青岛大学附属医院病理科诊断的200例T细胞淋巴瘤，从中筛选出5例CD20阳性T细胞淋巴瘤，复习文献，分析该疾病的临床病理学特点。 结果： 5例患者，均为男性，年龄范围47~64岁，平均年龄56岁，包括2例单形性嗜上皮性肠道T细胞淋巴瘤，2例皮肤蕈样霉菌病（1例为斑块期，1例为肿瘤期），1例胃肠道惰性T细胞淋巴组织增殖性疾病。免疫组织化学：5例患者均表达多种T细胞标志物（CD3、CD4、CD5、CD7、CD8），仅表达1种B细胞标志物CD20（其中3例患者首次诊断时CD20阴性，在疾病复发或进展后，二次活检诊断时CD20弥漫阳性），不表达CD79α及PAX5。5例患者EB病毒编码的小RNA（EBER）原位杂交均阴性，T细胞受体（TCR）重排均显示β链和/或γ链和/或δ链单克隆性重排，Ig重排均为多克隆性重排。5例患者均未应用利妥昔单抗治疗，截至2020年2月，4例患者带病生存，1例患者无病生存，其中蕈样霉菌病肿瘤期患者进展较快，生活质量差。 结论： CD20阳性T细胞淋巴瘤极少见，其预后与T细胞淋巴瘤具体类型、临床分期和初始治疗效果密切相关。CD20阳性表达提示疾病复发或进展，预后相对差。当T细胞淋巴瘤CD3表达缺失时，易误诊为B细胞淋巴瘤，联合运用多种免疫组织化学抗体及分子检测，可提高诊断的准确性。.
Keywords: Gene rearrangement, T-lymphocyte; Lymphoma, B-cell; Lymphoma, T-cell; Rituximab.