NCIt definition : A large B-cell lymphoma usually presenting as a serous effusion without detectable
tumor masses. It is universally associated with human herpes virus 8 (HHV8), also
called Kaposi sarcoma-associated herpesvirus. It mostly occurs in the setting of immunodeficiency.
The most common sites of involvement are the pleural, pericardial, and peritoneal
cavities. Rare HHV8-positive lymphomas indistinguishable from primary effusion lymphomas
(PEL) present as solid tumor masses, and have been termed extracavitary PEL. The prognosis
is extremely unfavorable. (WHO 2017);
Alternative definition : NCI-GLOSS: A rare, aggressive (fast-growing) type of B-cell non-Hodgkin lymphoma marked
by an abnormal build-up of fluids in a body cavity. It usually occurs together with
a human herpesvirus in people who have weakened immune systems, such as in AIDS.;