Overview

Kaposi sarcoma is a type of cancer that forms in the lining of blood vessels and lymph vessels. The cancer forms growths of cells, called lesions, on the skin. The lesions often form on the face, arms and legs. The lesions may look pink, red, purple or brown.

Lesions also can appear on the genitals or in the mouth. In severe Kaposi sarcoma, lesions can be in the digestive tract and lungs.

The cause of Kaposi sarcoma is infection with the virus human herpes virus 8, also called HHV-8. In healthy people, this infection usually causes no symptoms because the immune system keeps it under control. In someone with a weakened immune system, however, HHV-8 can lead to Kaposi sarcoma.

Types of Kaposi sarcoma include:

  • AIDS-related or epidemic Kaposi sarcoma. This type happens in people infected with human immunodeficiency virus, also called HIV. HIV is the virus that causes AIDS.
  • Transplant-associated or iatrogenic Kaposi sarcoma. This type happens in people who take medicine to control the immune system after an organ transplant.
  • Classic Kaposi sarcoma. This type occurs in older adults of Eastern European, Mediterranean and Middle Eastern descent. It usually grows slowly and can cause swelling in areas such as the legs.
  • Endemic Kaposi sarcoma. This type affects young people in Africa. It can grow slowly on the skin or quickly inside the body.

Symptoms

Kaposi sarcoma signs and symptoms include:

  • A growth on the skin that may be raised or flat.
  • A growth on the skin that looks red, purple or brown in color.

The growths, called lesions, most often happen on the face, arms or legs. They usually don't cause discomfort.

If Kaposi sarcoma isn't treated, the lesions can get bigger. They may cause:

  • Swelling in the lower legs caused by blood flow problems.
  • Enlarged lymph nodes.
  • Skin that appears red or purple in color and may be painful and itchy.

Kaposi sarcoma also can affect areas you can't see. It can grow in the digestive tract or lungs. When Kaposi sarcoma happens in the digestive tract, symptoms may include:

  • Diarrhea.
  • Nausea.
  • Stomach pain.
  • Vomiting.
  • Weight loss.

When to see a doctor

Make an appointment with a doctor or other healthcare professional if you have symptoms that worry you.

Causes

The human herpes virus 8 causes Kaposi sarcoma. Healthcare professionals believe this virus, also called HHV-8, spreads from person to person through saliva. It also may be passed through blood.

When a healthy person gets the HHV-8 virus, that person's immune system is likely to control it. The virus may stay in the body, but it doesn't cause any problems. If something happens to weaken the immune system, the virus may no longer be controlled. This can lead to Kaposi sarcoma.

Risk factors

Risk factors for Kaposi sarcoma include:

  • HIV infection. HIV is the virus that causes AIDS.
  • Older age. Kaposi sarcoma can happen at any age. It's most common in adults between 50 and 70.
  • Living in certain parts of the world. Kaposi sarcoma is rare in the United States. It's most common in the Mediterranean, Eastern Europe and sub-Saharan Africa.
  • Medicines that weaken the immune system. Some conditions are treated with medicine to control the immune system. Medicine that works in this way often is used after organ transplant surgery.
By Mayo Clinic Staff