Human Herpesvirus 8-Unrelated Primary Effusion Lymphoma-Like Lymphoma in an Elderly Korean Patient with a Good Response to Rituximab Plus Cyclophosphamide, Doxorubicin, Vincristine, and Prednisolone.

Primary effusion lymphoma (PEL) is a rare type of non-Hodgkin's lymphoma arising from a B-cell lineage characterized by the formation of malignant effusion in body cavities without evidence of a detectable tumor. The effusion contains tumor cells universally infected with human herpesvirus 8 (HHV8), which is the critical factor differentiating PEL from HHV8-unrelated PEL-like lymphoma (PEL-LL). This report describes a 77-year-old male patient with pleural effusion and ascites, containing lymphoma cells expressing a B-cell phenotype, but without markers of HHV8 in immunocytochemical analysis. The patient was diagnosed with PEL-LL and treated with six cycles of rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP), which resulted in a complete remission. The patient is currently disease-free 15 months post-treatment. To the best of our knowledge, this is the first report on administration of R-CHOP in a PEL-LL patient in South Korea.