Human herpesvirus 8-related diseases: Histopathologic diagnosis and disease mechanisms.

The emergence of HIV/AIDS more than three decades ago led to an increased incidence of diseases caused by HHV8 co-infection, particularly Kaposi sarcoma, primary effusion lymphoma, and multicentric Castleman disease. Over time, the development of highly effective AIDS therapies has resulted in a decreased incidence of HHV8-associated entities, which are now more commonly found in patients with undiagnosed and/or untreated AIDS. Due to their rarity, some of these diseases may be difficult to recognize without appropriate clinical information. This article provides an overview of HHV8-related disorders, with a focus on their morphologic and phenotypic features, and includes a brief overview of laboratory methods used to detect HHV8. Disease mechanisms by which the HHV8 virion promotes tumorigenesis are also reviewed.