Clinical aspects of epidemic Kaposi's sarcoma.

Whereas previously KS represented a very rare and obscure neoplasm, it has become over the past decade a significant disease. Its appearance in various well defined risk populations and in immunosuppressed individuals and the mounting epidemiological evidence that KS may well represent a sexually transmitted disease in certain groups make KS an important tumour to study as a model for carcinogenesis. Among the various forms of KS described, it is the epidemic form of KS, most frequently associated with HIV infection, that is now the most prevalent form seen around the world. Clinically, the mucocutaneous and lymph node involvement are its most frequently recognized manifestations. Skin lesions in epidemic KS, unlike those in classical KS, appear anywhere on the skin or oral mucosa and at any age in patients with AIDS. Visceral lesions are often present, sometimes in the absence of cutaneous KS. Epidemic KS is rarely the cause of death in AIDS patients, even in those with visceral involvement, unlike the HIV-1 unrelated African endemic form of KS, which is an aggressive and malignant tumour. HIV testing is necessary to establish the diagnosis of AIDS in patients with epidemic KS, even in those patients with risk factors for HIV infection, since epidemic KS may represent an epidemic disease caused by a yet unidentified transmissible agent distinct from HIV. Concurrent transmission of HIV and the putative "KS agent" may have occurred in the homosexual patients with AIDS in whom KS has been so prevalent, and the recently identified form of epidemic KS in individuals not infected with HIV may well become yet a new form of this curious disease.