Alkhasawneh Ahmad, Mohamed Khaled S, Desai Ketav, Omman Reeba, Baskovich Brett
Pathology, University of Florida College of Medicine, Jacksonville, USA.
Pathology and Laboratory Medicine, University of Florida College of Medicine, Jacksonville, USA.
Cureus. 2022 Jun 3;14(6):e25637. doi: 10.7759/cureus.25637. eCollection 2022 Jun.
Primary effusion lymphoma (PEL) is a rare B-cell lymphoma that usually occurs in the setting of HIV infection, and it is associated with Human Herpesvirus-8 (HHV-8). Diagnosis of PEL is usually established in cell centrifuge, cell block, or tissue examination, and there are few reports describing flow cytometry findings in PEL. We report two male patients (a 34-year-old and a 56-year-old) with a history of HIV infection. The first patient presented with ascites and abdominal pain, and the second patient presented with chest pain and parapneumonic pleural effusion. Cavitary fluid examination showed large pleomorphic neoplastic lymphoid cells with plasmablastic morphology. Flow cytometry analysis of the neoplastic lymphocytes showed increased forward scatter and side scatter with intermediate to a high level of CD38 expression. In one patient, lymphoma cells showed bright CD45 expression with dim expression of CD19 and kappa light chain. There was no significant expression of CD20 or any T/NK cell markers in either case. Immunohistochemistry for CD30 was positive in one patient. Immunohistochemistry for HHV-8 and in situ hybridization for Epstein-Barr virus-encoded small RNAs (EBER) was positive on cell blocks in both cases, consistent with the diagnosis of primary effusion lymphoma. PEL should be considered in the differential diagnosis of CD20-negative hematopoietic neoplasms, and flow cytometry may provide helpful clues for the diagnosis of PEL as part of the workup for pleural effusion with cytologically malignant cells.
原发性渗出性淋巴瘤（PEL）是一种罕见的B细胞淋巴瘤，通常发生于HIV感染的背景下，且与人类疱疹病毒8型（HHV-8）相关。PEL的诊断通常通过细胞离心、细胞块或组织检查来确立，很少有报告描述PEL的流式细胞术检测结果。我们报告了两名有HIV感染史的男性患者（一名34岁，一名56岁）。第一名患者表现为腹水和腹痛，第二名患者表现为胸痛和肺炎旁胸腔积液。空洞液检查显示有大量具有浆母细胞形态的多形性肿瘤性淋巴细胞。对肿瘤性淋巴细胞进行流式细胞术分析显示前向散射和侧向散射增加，CD38表达水平为中等至高。在一名患者中，淋巴瘤细胞显示CD45表达明亮，CD19和κ轻链表达暗淡。两种情况下均无CD20或任何T/NK细胞标志物的显著表达。一名患者的CD30免疫组化呈阳性。两例患者细胞块的HHV-8免疫组化和爱泼斯坦-巴尔病毒编码小RNA（EBER）原位杂交均为阳性，符合原发性渗出性淋巴瘤的诊断。在CD20阴性造血肿瘤的鉴别诊断中应考虑PEL，流式细胞术可为作为伴有细胞学恶性细胞的胸腔积液检查一部分的PEL诊断提供有用线索。
