What Is Kaposi’s Sarcoma?

Cancer is made up of abnormal cells that multiply constantly.

To help you understand what is happening when you have cancer, it helps to know how your body works normally. Your body is made up of tiny building blocks called cells. Healthy cells grow and multiply when the body needs them, and die out when the body does not need them.

Cancer is made up of abnormal cells that grow whether they are needed or not. A sarcoma is a cancer that grows in body tissues. It can grow in bones, cartilage, blood vessels, fat, muscles, or tendons and other stringy tissue.

In Kaposi’s sarcoma (KS), cancer cells grow below the skin. They can also grow in the mucous membranes in the nose, mouth, lung, and anus. KS causes purple, brown, or red patches on the skin. These patches are called lesions. KS lesions can spread to other organs in the body, such as the liver and lungs. KS gets its name from Dr. Moritz Kaposi, who first described it.

The lesions can be deforming but are not usually life threatening. In most cases, the lesions cause no symptoms. Sometimes, though, the lesions can cause pain or swelling of the skin. When KS involves the liver, lungs, digestive system, or lymph nodes, other symptoms can develop. For example, KS tumors in the lungs can cause breathing problems.

One type of KS occurs in people with human immunodeficiency virus (HIV). This is the virus that causes acquired immunodeficiency syndrome (AIDS). Other types of KS occur in people who don’t have HIV and AIDS.

Infection with human herpes virus 8 (HHV-8) causes AIDS-related KS. HHV-8 creates an inflammatory state needed for KS to grow. KS is especially aggressive in people with AIDS, because HIV infection weakens the immune system. This allows the tumors grow more easily.