multicentric, malignant neoplastic vascular proliferation characterized by the development of bluish-red cutaneous nodules, usually on the lower extremities, most often on the toes or feet, and slowly increasing in size and number and spreading to more proximal areas; occurs spontaneously in Jewish and Italian males; aggressive variant in young children is endemic in some areas of Africa; a third form occurs in about 0.04% of kidney transplant patients; there is also a high incidence in AIDS patients; human herpesvirus 8 is the suspected cause.