HIV-associated plasmablastic multicentric Castleman disease is an increasingly frequent diagnosis. Kaposi sarcoma herpesvirus is found in the monotypic polyclonal plasmablasts that characterize this disease. Unlike Kaposi sarcoma, the incidence does not correlate with CD4 cell count or use of highly active antiretroviral therapy. It is a relapsing and remitting illness, and diagnostic criteria are emerging that define disease activity based on the presence of a fever and raised C-reactive protein coupled with a list of clinical features. Treatment protocols increasingly stratify therapy according to performance status and organ involvement. I advocate rituximab monotherapy for good performance status patients without organ involvement and rituximab with chemotherapy for more aggressive disease. The success of antiherpesvirus agents in controlling active disease is limited, but valganciclovir may have a role as maintenance therapy in the future.