Primary effusion lymphoma

Primary effusion lymphoma (PEL) is a B-cell lymphoma.

Causes
It is caused by Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV-8).

In most cases, the lymphoma cells are also infected with Epstein Barr virus (EBV).

PEL most commonly arises in patients with underlying immunodeficiency, such as AIDS.

The condition can exist in the absence of HHV-8 and HIV, though this is rare.

Presentation
PEL is unusual in that the majority of cases arise in body cavities, such as the pleural space or the pericardium; another name for PEL is "body cavity lymphoma".

A case has been described that was positive for CD38, CD71 and CD30.

History
It was recognized as a unique type of lymphoma only after the discovery of KSHV in 1994.

Prognosis
It is generally resistant to cancer chemotherapy drugs that are active against other lymphomas, and carries a poor prognosis.

Sirolimus has been proposed as a treatment option.