BACKGROUND
Primary effusion lymphoma (PEL) is a rare and distinct type of high-grade non-Hodgkin’s B-cell lymphoma (NHL) [1]. Human herpesvirus type 8 (HHV8) been directly linked to PEL since the late 1990s [2].
PEL is characterized by the presence of significant serous lymphomatous fluid collection in the pleural, pericardial, and peritoneal cavities without detectable solid tumor masses [3].
It most often occurs in immunocompromised patients such as in the advanced stages of Acquired Immune Deficiency Syndrome (AIDS) [4]. PEL has also been reported in immunocompetent elderly patients from HHV-8 endemic areas such as central and southern Africa and the Mediterranean area. It typically involves Middle-aged patients with a significant male predominance of 6:1 [5].
The clinical scenario is directly related to the body cavity involved, the amount of the effusion, and its interaction with the adjacent structures [6].
The diagnosis of PEL is based on cytological immunophenotypically and viral characteristics of the involved effusion. PEL is suspected in the presence of diffuse large cells with abundant basophilic cytoplasm and irregular nuclei with prominent nucleoli resembling plasma cells [7].
The lymphoma cells usually express the leukocyte origin marker CD45 but lack the typical B or T cell phenotype while markers of plasma cell differentiation, CD38, and CD138 are usually present [8].
Uniform treatment of PEL has not been properly established, and patients are generally treated with combined chemotherapy used for aggressive lymphomas known as the ”CHOP” protocol, consisting of cyclophosphamide, hydroxydaunorubicin, oncovin (vincristine) and prednisone.   Despite complete response rates of 43 to 57%, the median survival is still poor and estimated as six to nine months, due to early and usually refractory relapses [9].