A form of cancer caused by a type of herpesvirus that occurs mainly in the skin but may also occur in lymph nodes, internal organs and mucosal areas. The classic type tends to occur mainly on the extremities and internal organ involvement is common in adults. An aggressive form of the condition occurs in children and also involves the lymph nodes. The condition is aggressive in children but fairly benign in adults. Symptoms depend on the extent of internal organ and lymphatic system involvement. See also Kaposi sarcoma, Endemic African form