Kaposi sarcoma, sometimes called KS, is a type of cancer. It causes lesions (abnormal tissue) to grow in different parts of the body, including:

• The skin
• Lymph nodes
• Mucous membranes (the lining of the mouth, nose, and throat)
• Other organs

These lesions are usually red or purple. They are made of cancer cells, new blood vessels, and blood cells. The lesions may begin in more than one place in the body at the same time. This makes Kaposi sarcoma different from other cancers.

Kaposi sarcoma is caused by infection with human herpesvirus-8 (HHV-8). This virus is also called Kaposi sarcoma-associated herpesvirus (KSHV). Most people infected with this virus don't get Kaposi sarcoma. But certain people who get this virus are more likely to develop one of the types of Kaposi sarcoma:

• People with weakened immune systems due to HIV can develop epidemic (HIV-associated) Kaposi sarcoma.
• People with weakened immune systems due to medicines they need to take after an organ transplant can develop iatrogenic (transplant-related) Kaposi sarcoma.
• Older men of Mediterranean or Eastern European Jewish heritage can develop classic Kaposi sarcoma.
• Young men in Africa can develop endemic (African) Kaposi sarcoma.

Kaposi sarcoma usually starts out as one or more red, purple, or brown skin lesions on the legs and feet. They are most often on the ankles or soles of the feet. Over time, lesions may form in other parts of the body. The lesions may not cause symptoms. But sometimes the lesions can cause problems, especially as you get more of them and they grow bigger. For example:

• Pressure from the lesions may block the flow of lymph and blood in the legs and cause painful swelling
• If lesions grow in your stomach or intestines, they can bleed and may cause abdominal (belly) pain and diarrhea
• Lesions in the lungs can also bleed and may cause shortness of breath

To find out whether you have Kaposi sarcoma, your health care provider:

• Will ask about your medical and family history
• Will do a physical exam
• May order a chest x-ray to look for Kaposi sarcoma in the lungs
• May do a biopsy to check for Kaposi sarcoma lesions in the skin
• May do an endoscopy to check for Kaposi sarcoma in the stomach and intestines
• May do a bronchoscopy to check for Kaposi sarcoma in the lungs

If you do have Kaposi sarcoma, you will likely need blood and imaging tests to find out if the cancer has spread to other parts of the body.

Which treatment(s) you get will depend on

• The type of Kaposi sarcoma you have
• How many lesions you have and where in the body they are
• What kinds of problems the lesions are causing
• Your overall health

For people who have epidemic (HIV-associated) Kaposi sarcoma, taking HIV medicines may be enough to treat the Kaposi sarcoma. For people who have iatrogenic (transplant-related) Kaposi sarcoma, changing the dose of the medicines or switching medicines may be helpful. But some people with these types of Kaposi sarcoma will need additional treatment.

The treatment options for Kaposi sarcoma may include:

• Radiation therapy
• Surgery
• Cryosurgery, a treatment that uses an instrument to freeze and destroy abnormal tissue
• Chemotherapy
• Immunotherapy

NIH: National Cancer Institute