Which cancer is associated with AIDS, known for its appearance as dark lesions on the skin?

Kaposi's sarcoma is a type of cancer that is significantly associated with AIDS and is one of the most recognizable malignancies in individuals with immunocompromised states, such as those living with HIV. It is characterized by the development of dark purple or brown lesions on the skin and can also affect other organs. The lesions result from the proliferation of blood vessels and are indicative of the underlying infectious process.

This cancer arises from endothelial cells and is linked to infection with Human Herpesvirus 8 (HHV-8). In patients with AIDS, the weakened immune system allows HHV-8 to reactivate and lead to the development and spread of Kaposi's sarcoma. The presence of these lesions can often be one of the first signs clinicians look for when assessing the health of a patient with HIV/AIDS, marking its association with this population.

Neoplasms such as melanoma, carcinoma, and lymphoma are significant in their own right, but they do not have the same specific connection to AIDS as Kaposi's sarcoma. Each of those cancers presents differently and is associated with a variety of risk factors not limited to immune status, unlike Kaposi's sarcoma, which is specifically noted for its association with HIV/AIDS.