Prolonged survival in a patient with human herpesvirus-8-negative primary effusion lymphoma after combination chemotherapy with rituximab

Primary effusion lymphoma (PEL) is a unique clinicopathological entity usually associated with human herpesvirus-8 (HHV-8) infection. It occurs almost exclusively in human immunodeficiency virus (HIV) -infected individuals. We presented a rare case of HIV-negative PEL in an elderly HHV-8-negative patient who developed cardiac tamponade due to pericardial effusion. The patient was treated with rituximab and cyclophosphamide, doxorubicin, vincristine and prednisolone (CHOP). This disease generally has a poor prognosis; however, this patient achieved complete remission and remains without signs of disease 30 months after the last treatment. Because most HIV-negative and HHV-8- negative PEL cases show pan-B-cell markers, there is considerable usage of rituximab, though its optimal usage for PEL is unclear. To the best of our knowledge, there have been five reported cases where rituximab treatment has been used against HIV-negative and HHV-8-negative PEL. The clinical courses of these cases were relatively good without specific adverse effects. HIV-negative and HHV-8-negative PEL appears to be a reasonably new clinicopathological entity. While further investigation will of course be needed, the use of rituximab is worth considering for treatment of such patients.