Fifty years of multicentric Castleman's disease.

Benjamin Castleman first described multicentric Castleman's disease (MCD) in a series of cases in 1954. Interest in MCD has grown in recent years following an association with human immunodeficiency virus (HIV) infection. Castleman's disease is separated into localized disease and MCD. The latter is characterized by polylymphadenopathy and multiorgan involvement. Histologically, Castleman's disease is divided into the hyalinized vascular form and a plasma cell variant, the former being more common in localized disease and the latter more common in MCD. MCD is associated with Kaposi's sarcoma herpesvirus (KSHV) infection, which is alternatively termed human herpesvirus 8 (HHV8). This virus encodes a homologue of interleukin 6 (vIL 6), which may mediate some systemic features of MCD. The diagnosis of Castleman's disease is established by biopsy and treatment is often based on published case reports only, as there are no randomized trials of therapy. Surgery has less of a role in MCD than in localized disease, but debulking by splenectomy may be useful to alleviate haematological sequelae. Systemic treatments for MCD have included chemotherapy, anti-herpesvirus treatments to reduce the KSHV viral load, highly active antiretroviral therapy (HAART) to reduce HIV viraemia and latterly monoclonal antibodies against both IL 6 and CD20. The introduction of HAART has altered the natural history of HIV infection; however, its impact on MCD is difficult to ascertain. Optimization and consensus in treatment of these patients remains a target for the future.