A cancer that causes lesions in the soft tissues.

Kaposi sarcoma is a kind of cancer that forms in the lining of blood vessels and lymph vessels. It causes growths of cells, called lesions, on the skin. Sometimes lesions happen in the lungs or digestive system. Kaposi sarcoma most often affects people with weakened immune systems.

Purple, red, pink or brown skin blotches are a common sign. They often form on the face, arms and legs. They also may appear in the mouth or on the genitals.

Treatment may include surgery, laser therapy or medicines for small lesions. Radiation or chemotherapy might be used if there are many lesions.