An organ or organ-system abnormality that consists of uncontrolled autonomous cell-proliferation which can occur in any part of the body as a benign or malignant neoplasm (tumor).

Kaposi sarcoma (KS) is an invasive angioproliferative inflammatory condition that occurs commonly in men infected with human immunodeficiency virus (HIV; see 609423). In the early stages of KS, lesions appear reactive and are stimulated to grow by the actions of inflammatory cytokines and growth factors. In the late stages of KS, a malignant phenotype that appears to be monoclonal can develop. Infection with human herpesvirus-8 (HHV-8), also known as KS-associated herpesvirus (KSHV), is necessary but not sufficient for KS development. Coinfection with HIV markedly increases the likelihood of KS development, and additional environmental, hormonal, and genetic cofactors likely contribute to its pathogenesis (summary by Foster et al., 2000). Suthaus et al. (2012) noted that HHV-8 is the etiologic agent not only of KS, but also of primary effusion lymphoma and plasma cell-type multicentric Castleman disease (MCD).

An abnormal accumulation of fluid beneath the skin, or in one or more cavities of the body.

A hyperpigmented circumscribed area of change in normal skin color without elevation or depression of any size.