Final answer:
Kaposi sarcoma is a cancer caused by the Kaposi's sarcoma-associated herpesvirus (KSHV) and commonly presents with red, raised skin lesions. It becomes opportunistic and more aggressive in people with compromised immune systems, such as those with AIDS, who experience a loss of T cells.
Step-by-step explanation:
Kaposi sarcoma is a type of cancer that affects the cells lining the blood and lymphatic vessels. It is caused by the Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV-8). This cancer often presents with red, raised, scab-like skin lesions and can be the most common opportunistic cancer in people with AIDS, affecting 10 to 20 percent of AIDS patients. In people with healthy immune systems, KSHV typically does not cause illness. However, among individuals with compromised immune systems, such as those with AIDS, it can lead to rapidly progressing and severe symptoms. Kaposi sarcoma was previously considered a disease of the elderly, but the version associated with AIDS is much more aggressive.
In the early stages of the AIDS crisis, young patients in cities like New York and San Francisco were frequently diagnosed with Kaposi sarcoma, which was one of the first signs of the severity of the disease. It was initially called 'gay cancer' due to its prevalence in the gay community, but this term was later dropped as it became clear that the disease was not confined to this group. The presence of Kaposi sarcoma can indicate a significant weakening of the immune system, often signaled by a drastic reduction in T cells, which are targeted by the HIV virus.