Primary effusion lymphoma

Primary effusion lymphoma (PEL) is a rare, aggressive lymphoma that involves 1 or more of the serous (pleural, peritoneal, and peritoneal) cavities without other tumor masses and is associated with the human herpesvirus 8 (HHV-8), often in the setting of immunodeficiency. PEL occurs predominantly in men with acquired immunodeficiency syndrome (AIDS) but can be seen in iatrogenically immunosuppressed transplant patients and elderly individuals. The effusions show a dispersed population of large pleomorphic cells with eccentrically located nuclei, 1 or more prominent nucleoli, a perinuclear pallor, and moderately abundant cytoplasm. Binucleated and multinucleated cells and mitotic figures are seen commonly. This lymphoma frequently has an indeterminate immunophenotype that is not clearly B cell or T cell in origin, but it is often positive for CD45, CD30, and epithelial membrane antigen. In addition to HHV-8 positivity, many patients also have seropositive results for HIV and Epstein-Barr virus. PEL usually exhibits a complex karyotype without a characteristic aberration. The differential diagnosis typically includes other high-grade lymphomas that occur in HIV-infected patients, immunosuppressed patients, and elderly individuals. The prognosis of this high-grade lymphoma is usually poor, with a survival of only a few months, even with chemotherapy.