HHV8-negative effusion based lymphoma: A series of 17 cases at a single institution

Introduction: Human herpesvirus 8-positive (HHV8+) primary effusion lymphoma is a well-recognized clinicopathologic entity. In contrast, HHV8-negative (HHV8-) effusion-based lymphoma (EBL) is incompletely characterized and under-recognized. We describe 17 cases of HHV8- EBL at our institution. Materials and methods: Cytology and available immunohistochemistry and cytogenetics were reviewed. Patient demographics, history, and outcome were obtained from medical records. Results: The effusions were pleural (n = 9; 53%), peritoneal (n = 4; 24%), pericardial (n = 3; 18%), and pleural and pericardial (n = 1; 6%). Fifteen cases (88%) were CD20+ and 15 had sufficient information for classification by Hans algorithm (CD10, BCL6, MUM1): 11 (73%) nongerminal center and 4 (27%) germinal center phenotype. Epstein-Barr virus in situ hybridization was negative in 16 cases (94%). Three of 14 cases were MYC+ by immunohistochemistry. Fluorescence in situ hybridization, performed on 5 of the 17 cases, showed a MYC rearrangement in 1 case and a BCL6 rearrangement in 2 cases. Most patients were elderly (median age 86 years) and female (82%). Human immunodeficiency virus testing results, available in 4 patients, were negative. Seven (41%), including 1 of 2 heart transplant recipients, had congestive heart failure. Follow-up (5 days to 12 years) was available for 16 patients including 4 who survived ≥8 years. Only 1 of the 8 known deaths was clinically attributed to lymphoma. Conclusions: HHV8- lymphomas that occur in body cavity effusions without detectable lymphomatous masses are usually composed of large CD20+ lymphoid or lymphoplasmacytoid cells. In contrast to HHV8+ primary effusion lymphoma, patients with HHV8- EBL are usually elderly, lack a documented human immunodeficiency virus-positive history, and have a longer disease specific survival.