A rare neoplasm of large B-cells usually presenting as serious effusions without detectable tumor masses. The most common sites of involvement are the pleural, pericardial, and peritoneal cavities. It is associated with HUMAN HERPESVIRUS 8, most often occurring in the setting of immunodeficiency.

Synonyms: Lymphomas, Primary Effusion Effusion Lymphomas, Primary Primary Effusion Lymphomas Effusion Lymphoma, Primary Lymphoma, Primary Effusion Primary Effusion Lymphoma