Cytologic diagnosis of primary effusion lymphoma in an HIV-negative patient.

Primary effusion lymphoma (PEL) is an unusual and rare type of non-Hodgkin's lymphoma characterized by lymphomatous effusion of pleural, pericardial or peritoneal cavities without lymphadenopathy or organomegaly. It is associated with human herpes virus-8 (HHV-8) and occurs most often in immunodeficient patients. We present a case of PEL in a 69-year-old male presenting with pleural effusion and ascites. Fluid aspiration showed a monomorphic population of atypical lymphoid cells, which were medium- to large-sized, with mono- or binucleated hyperchromatic nuclei and a small to moderate amount of basophilic cytoplasm containing cytoplasmic vesicles. Immunohistochemically, the lymphoid cells expressed CD138 and multiple myeloma oncogene 1, were positive for HHV-8, and were monoclonal for immunoglobulin heavy chain gene rearrangement. They were negative for Epstein-Barr virus by in situ hybridization. Unfortunately, the patient died during the first course of chemotherapy with cyclophosphamide, vincristine and prednisone.