Plasma cell differentiation (PCD) is frequently observed in some entities of non-Hodgkin B cell lymphoma, including both low-grade and high-grade lymphomas. However, except for plasmablastic lymphoma and primary effusion lymphoma, EBV⁺ B cell lymphoproliferative disorder (LPD) with PCD has not been well addressed due to its rarity. We clinicopathologically examined five cases of nodal EBV⁺ polymorphic B cell LPD with PCD (PBLPD-PCD) initially diagnosed as polymorphic EBV⁺ diffuse large B cell lymphoma, not otherwise specified (DLBCL-NOS) with PCD (n = 3) and methotrexate-associated B cell LPD (MTX-associated B-LPD) (n = 2). One case had a concomitant brain lesion which was clinically diagnosed as EBV-related encephalitis. This patient received therapy with vidarabine, and both the brain lesion and the nodal EBV⁺ PBLPD-PCD lesions disappeared. Another case was characterized by Mott cell differentiation. This case was the first reported case of EBV⁺ B cell lymphoma or LPD with Mott cell differentiation. The two cases of MTX-associated B cell LPD which arose in patients with rheumatoid arthritis spontaneously regressed after MTX cessation. TCRγ and IGH PCR analysis was performed in four cases. Two cases had TCRγ rearrangements, but no IGH rearrangements. The other two cases had no rearrangements in these genes. We concluded that nodal EBV⁺ PBLPD-PCD is rare, with heterogeneous characteristics. PCR analysis revealed that nodal EBV⁺ PBLPD-PCD may have only TCR clonality and no IGH clonality. Considering the partial or complete loss of CD20 expression on the tumor cells, this result may be confusing for accurate diagnosis of EBV⁺ PBLPD-PCD, and pathologists need to be aware of this phenomenon to avoid misdiagnosis.

在非霍奇金B细胞淋巴瘤的某些实体中经常观察到浆细胞分化（PCD），包括低度和高度淋巴瘤。但是，除了浆母细胞性淋巴瘤和原发性渗出性淋巴瘤，由于其稀有性，EBV ⁺ B细胞淋巴组织增生性疾病（LPD）与PCD并没有得到很好的解决。我们在临床病理上检查了5例淋巴结EBV ⁺多态性B细胞LPD伴PCD（PBLPD-PCD），最初诊断为多形性EBV ⁺弥漫性大B细胞淋巴瘤，未另作说明（DLBCL-NOS）伴PCD（n  = 3）和甲氨蝶呤相关的B细胞LPD（MTX相关的B-LPD）（n = 2）。1例伴有脑部病变，临床上被诊断为EBV相关性脑炎。该患者接受了维达拉滨治疗，脑部病变和淋巴结EBV ⁺ PBLPD-PCD病变均消失。另一例以Mott细胞分化为特征。该病例是首次报道的具有Mott细胞分化的EBV ⁺ B细胞淋巴瘤或LPD病例。在类风湿关节炎患者中出现的2例与MTX相关的B细胞LPD发生在MTX停止后自发消退。在4例中进行了TCRγ和IGH PCR分析。2例TCRγ重排，无IGH重排。其他两个病例在这些基因中没有重排。我们得出的结论是，节点EBV ⁺ PBLPD-PCD很罕见，具有异质性。PCR分析显示，结点EBV ⁺ PBLPD-PCD可能只有TCR克隆，而没有IGH克隆。考虑到肿瘤细胞上CD20表达的部分或全部丧失，该结果可能难以准确诊断EBV ⁺ PBLPD-PCD，病理学家需要意识到这一现象，以避免误诊。