Human Herpesvirus 8-Negative and Epstein-Barr Virus-Positive Effusion-Based Lymphoma in a Patient with Human Immunodeficiency Virus

Human herpesvirus 8-negative effusion-based large B-cell lymphoma: a distinct entity with unique clinicopathologic characteristics

Rare cases of human herpesvirus 8 (HHV8)-negative effusion-based large B-cell lymphoma (EB-LBCL) occur in body cavities without antecedent or concurrent solid mass formation. In contrast to HHV8 + primary effusion lymphoma (PEL), EB-LBCL has no known association with HIV or HHV8 infection. However, the small sample sizes of case reports and series worldwide, especially from non-Japanese regions, have precluded diagnostic uniformity. Therefore, we conducted a retrospective, multi-institutional study of 55 cases of EB-LBCL and performed a comprehensive review of an additional 147 cases from the literature to identify distinct clinicopathologic characteristics. In our study, EB-LBCL primarily affected elderly (median age 80 years), immunocompetent patients and manifested as lymphomatous effusion without a solid component. The lymphomatous effusions mostly occurred in the pleural cavity (40/55, 73%), followed by the pericardial cavity (17/55, 31%). EB-LBCL expressed CD20 (53/54, 98%) and PAX5 (23/23, 100%). Most cases (30/36, 83%) were of non-germinal center B-cell subtype per the Hans algorithm. HHV8 infection was absent (0/55, 0%), while Epstein-Barr virus was detected in 6% (3/47). Clinically, some patients were managed with drainage alone (15/34, 44%), while others received rituximab alone (4/34, 12%) or chemotherapy (15/34, 44%). Eventually, 56% (22/39) died with a median overall survival (OS) of 14.9 months. Our findings were similar to those from the literature; however, compared to the non-Japanese cases, the Japanese cases had a significantly higher incidence of pericardial involvement, a higher rate of chemotherapy administration, and longer median OS. Particularly, we have found that Japanese residence, presence of pericardial effusion, and absence of MYC rearrangement are all favorable prognostic factors. Our data suggest that EB-LBCL portends a worse prognosis than previously reported, although select patients may be managed conservatively. Overall, EB-LBCL has distinct clinicopathologic characteristics, necessitating the establishment of separate diagnostic criteria and consensus nomenclature.

Primary Effusion Lymphoma: A Timely Review on the Association with HIV, HHV8, and EBV

Primary effusion lymphoma (PEL) is defined by the WHO classification as a large B-cell neoplasm without detectable tumor masses. It is universally associated with HHV8, with most cases occurring in the setting of immunodeficiency such as HIV infection, and a poor prognosis. Morphologically, the neoplastic cells range from immunoblastic, plasmablastic, to anaplastic; and phenotypically, most cases express plasma cell but not B-cell markers, i.e., plasmablastic. During the past decade, primary HHV8-negative effusion lymphoma has been reported. Such cases were considered in the WHO classification scheme as effusion-based lymphoma. We performed a systemic review of 167 HHV8-negative effusion lymphomas from the literature and found that only 42% were associated with a fluid overload state, and with low rates of HIV (6%) or EBV (21%) infection. Furthermore, most patients are old (or immunosenescent) with underlying medical conditions/comorbidities, most neoplasms are of B-cell phenotype, and the outcome is more favorable than that of HHV8-positive PEL. These distinctive findings supported our prior proposal of designating these HHV8-negative cases as type II PEL, in contrast to the classic or type I PEL as defined by the WHO. Furthermore, we propose an algorithmic approach for the diagnosis of PEL and its mimickers.

Age and CD20 Expression Are Significant Prognostic Factors in Human Herpes Virus-8-negative Effusion-based Lymphoma

Human herpes virus-8 (HHV-8)-negative effusion-based lymphoma (HHV-8-negative EBL) can be distinguished from primary effusion lymphoma based on clinical and pathologic findings. Although the morphology between the 2 is similar and they both originate from body cavities with serous effusions and are characterized by lack of tumor masses, HHV-8-negative EBL generally occurs in older patients, and has favorable response to therapy and better prognosis than primary effusion lymphoma. However, no systematic studies have investigated prognostic factors in patients with HHV-8-negative EBL. In this report, clinical and pathologic characteristics of 67 cases of HHV-8-negative EBL, including 2 of our own cases, were analyzed. Univariate analyses revealed older age (70 y and above), Japanese ethnicity, pericardial effusion, CD20 expression, and chemotherapy with rituximab were significantly favorable prognostic factors. Peritoneal effusion was identified as an unfavorable prognostic factor. In the multivariate analysis, age and CD20 expression were independent prognostic factors (P=0.013 and 0.003, respectively). A past history of induced fluid overload, hepatitis C viral infection, and peritoneal effusion were significantly correlated with patients aged below 70 years, while pericardial and pleural effusions were significantly correlated with patients aged 70 years and above. A comparison of cases with and without CD20 expression revealed that Japanese ethnicity and pericardial effusion were significantly correlated with CD20 expression, whereas a past history of induced fluid overload and peritoneal effusion were significantly correlated with the absence of CD20. We concluded that older age and CD20 expression are significant and favorable independent prognostic factors of HHV-8-negative EBL.