Kaposi's sarcoma: imaging overview.

Kaposi's sarcoma (KS), a low-grade malignancy that is associated with human herpesvirus-8 (HHV-8), is a multifocal tumor that most commonly affects mucocutaneous sites. It might also involve lymph nodes and visceral organs, in particular of the respiratory and gastrointestinal tract, but it can affect every organ system. Four forms of the disease have been recognized: the classic, the endemic, the transplant-associated, and the epidemic form. The endemic form, or African KS, currently accounts for 10%-50% of all cancers in adults and up to 25% of cancers in children in certain parts of Africa. The epidemic form or acquired immune deficiency syndrome (AIDS)-associated KS is a frequent neoplasm in bisexual and homosexual men with AIDS in the United States. Even though in North America and Europe the incidence of KS in men with AIDS has decreased significantly after the introduction of highly active antiretroviral therapy (HAART), in some developing countries, the incidence of KS keeps growing. The pathophysiology, clinical manifestations, imaging findings, and more relevant differential diagnoses are reviewed.