Classical Hodgkin's lymphoma arising in different host's conditions: pathobiology parameters, therapeutic options, and outcome.

Epidemiologic and molecular findings suggest that classical Hodgkin's lymphoma (CHL) is not a single disease but consists of more than one entity and may occur in different clinical settings. This review analyzes similarities and disparities among CHL entities arising in different host's conditions with respect to pathobiology parameters, therapeutic options, and outcome. For the purpose of this analysis, CHL entities have been subdivided according to the immune status of the host. In nonimmunosuppressed hosts, according to the age, CHL include pediatric, adult, and elderly forms, whereas, in immunosuppressed hosts, according to the type of immunosuppression, CHL include human immunodeficiency virus (HIV)-associated, iatrogenic, and post-transplant types. CHL entities in different settings are similar in morphology of neoplastic cells, expression of activation markers, and aberrations/activation of NFKB, JAK/STAT, and P13K/AKT pathways, but differ in the association with Epstein-Barr virus (EBV) infection, persistent B-cell phenotype, and cellular background composition. Large B-cell lymphomas resembling CHL may also be observed in the same clinical settings. These lesions, however, do not fulfill the diagnostic criteria of CHL and clinically display a very aggressive behavior. In this article, current treatment options for the CHL entities, especially for elderly CHL and HIV-associated CHL, are specifically reviewed. ABVD remains the gold standard both in nonimmunosuppressed or immunosuppressed hosts even if there are several data suggesting a possible improvement in outcome using the aggressive BEACOPP regimen in advanced stages. Refractory CHL, a clinical condition that may occur throughout the entire spectrum of CHL, is discussed separately.