An unusual cause of pleural effusion.

Primary effusion lymphoma (PEL) is a unique clinicopathological entity associated with human herpesvirus-8 (HHV-8) infection, occurring almost exclusively in human immunodeficiency virus (HIV)-infected individuals. We report a rare case of HHV-8-negative PEL in an HIV-negative elderly patient who presented with pleural effusion. The patient was treated with CHOP and Rituximab. As opposed to the general poor outcome of this disease, our patient achieved complete remission and is still without signs of disease 11 months after the last treatment.