- A multicentric, malignant neoplastic vascular proliferation characterized by bluish red cutaneous nodules, usually on the lower extremities, most often on the toes or feet; the nodules slowly increase in size and number and spread to more proximal sites. Tumors often remain confined to skin and subcutaneous tissue, but widespread visceral involvement may occur. The condition occurs endemically in certain parts of Central Africa and Central and Eastern Europe, and a particularly virulent and disseminated form occurs in immunocompromised patients such as transplant recipients and those with acquired immunodeficiency syndrome. Human herpesvirus 8 has been implicated as a causative agent.
- A lymphatic endothelial malignancy, rather than a true sarcoma, composed of multiple red or purple macules, papules, or nodules, that is first apparent on the skin or mucous membranes but may involve the internal organs. Once a rare disease seen primarily in elderly men of Mediterranean, African, or Ashkenazi descent (so-called classic KS), it is the most common cancer related to AIDS. In patients with AIDS, KS is believed to be sexually acquired due to acquisition of human herpesvirus 8. When KS is associated with AIDS, it progresses and disseminates rapidly to multiple skin sites, as well as the lymph nodes and visceral organs.
