Abstract
Background : Primary effusion lymphoma (PEL) is a rare human herpesvirus (HHV)-8-positive large B-cell lymphoma that arises in body cavities, without any detectable tumor masses. Many effusion-based lymphoma cases reported in Japan are HHV-8-negative, so that they are called PEL-like lymphomas (PEL-LLs). Herein, we report a case of PEL-LL, in which the pleural fluid showed cytologically atypical cells with multilobulated nuclei.
Case : A man in his 70 s, who had undergone surgery for lung cancer, colon cancer, prostatic leiomyosarcoma, and renal cell carcinoma, presented to us with dyspnea that developed during treatment for heart failure. Chest computed tomography (CT) revealed massive left pleural effusion. Cytological examination of the pleural fluid revealed many solitary atypical cells with a high nuclear-cytoplasmic (N/C) ratio. The atypical cells showed conspicuous multilobulated nuclei, increased fine chromatin, and distinct nucleoli, and based on the findings, we diagnosed malignant lymphoma. The results of immunohistochemical analysis of a cell block led to the diagnosis of diffuse large B-cell lymphoma (DLBCL), non-germinal center B-cell (GCB) type ; however, the patient was finally diagnosed as having PEL-LL, because no detectable tumor masses were found on imaging studies and blood examination showed negative results for HHV-8.
Conclusion : Since multilobulated nuclei are not usually observed in cases of DLBCL, a possibility of PEL or PEL-LL should be considered when atypical lymphoid cells with conspicuous multilobulated nuclei are found in body cavity fluids.
