Kaposi Sarcoma

(Kaposi's Sarcoma; Multiple Idiopathic Hemorrhagic Sarcoma)

ByVinod E. Nambudiri, MD, MBA, EdM, Harvard Medical School
Reviewed/Revised Jan 2024
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Kaposi sarcoma is a skin cancer that causes multiple flat pink, red, or purple patches or bumps on the skin. It is caused by human herpesvirus type 8 infection.

  • One or a few spots may appear on the toes or a leg, or spots may appear anywhere on the body or in the mouth or genital areas, then spread to other areas, including internal organs.

  • Although this cancer can often be identified by sight, doctors usually also do a biopsy.

  • Spots may be removed or treated with radiation therapy, but if the cancer is aggressive, treatment includes chemotherapy or interferon alfa.

There are many types of human herpesviruses. One of them, type 8, can cause Kaposi sarcoma, particularly in people with a weakened immune system.

There are 5 types of Kaposi sarcoma. The types occur in several distinct groups of people and act differently in each group. It occurs in the following:

  • Classic Kaposi sarcoma: This type affects older men, usually of Mediterranean, Eastern European, or Ashkenazi Jewish heritage.

  • Endemic Kaposi sarcoma: Endemic means this cancer occurs regularly in a certain place. It affects children and young adults from certain parts of Africa.

  • Iatrogenic Kaposi sarcoma: This type affects people whose immune system is weakened by medications that suppress the immune system (immunosuppressants) given after organ transplantation.

  • AIDS-associated Kaposi sarcoma (epidemic Kaposi sarcoma): This type affects people with AIDS.

  • Non-epidemic: This type has been increasingly recognized and occurs in men who are HIV-negative and who have sex with men.

Symptoms of Kaposi Sarcoma

Kaposi sarcoma usually appears as purple, pink, brown, or red spots or bumps on the skin. The cancer may grow to several inches or more as blue-violet to black, flat or slightly raised areas. Swelling may be present. Sometimes the cancer grows deeper into soft tissues and invades bone.

Cancer of mucosal surfaces, such as in the mouth, are blue to violet in color. In the digestive tract, the cancer can sometimes bleed excessively but usually causes no symptoms.

Classic Kaposi sarcoma

Men over age 60 with the classic type may develop several additional spots on the legs, but the cancer rarely spreads to other parts of the body and is almost never fatal.

In the 4 other types of Kaposi sarcoma, the cancer may be more aggressive. Similar-appearing spots develop, but they are often multiple and may occur anywhere on the body.

Classic Kaposi Sarcoma
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In classic Kaposi sarcoma, a small number of purple, pink, brown or red spots sometimes combine into blue-violet to black patches as shown here.
Image provided by Thomas Habif, MD.

AIDS-associated Kaposi sarcoma

Within several months, people with the AIDS-associated type develop spots that spread to other parts of the body, such as the face and torso, often including the mouth, where they cause pain with eating.

The spots may also develop in lymph nodes and internal organs, especially the digestive tract, where they can cause internal bleeding that leads to blood in the stool. Sometimes Kaposi sarcoma is the first symptom of AIDS.

AIDS-Associated Kaposi Sarcoma
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AIDS-associated Kaposi sarcoma is an aggressive cancer that occurs in people with HIV infection. It can develop on the skin, mouth (as shown here on the upper gums), digestive tract, and lymph nodes. The tumors cause blue or purple spots, patches, or lumps.
Image courtesy of Sol Silverman, Jr., via the Public Health Image Library of the Centers for Disease Control and Prevention.

Did You Know...

  • In the United States, most cases of Kaposi sarcoma occur in people with AIDS.

Iatrogenic Kaposi sarcoma (immunosuppressive Kaposi sarcoma)

This type typically develops several years after organ transplantation. It can be severe, and spots may rapidly develop.

Endemic Kaposi sarcoma

In children, the endemic type usually involves the lymph nodes. The children may or may not have spots on the skin. The disease is usually sudden, severe, and fatal.

In adults, the endemic type tends to cause slow-growing spots and patches on the skin similar to those of the classic type. The cancer rarely spreads to other parts of the body and is not likely to be fatal.

Non-epidemic Kaposi sarcoma

This recently described type typically manifests with individual spots similar to classic Kaposi sarcoma, but it occurs specifically in men who are HIV-negative and who have sex with men. The severity of this type is still being studied.

Diagnosis of Kaposi Sarcoma

  • Punch biopsy

Doctors diagnose Kaposi sarcoma by doing a punch biopsy, in which a small piece of skin is removed for examination under a microscope, is usually done to confirm the diagnosis of Kaposi sarcoma.

For people with AIDS or immunosuppression, doctors do other tests to determine where the cancer has spread. Doctors usually do a computed tomography (CT) scan of the chest and the abdomen and do other tests depending on the person's symptoms.

Punch Biopsy
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To remove a small piece of skin for examination under a microscope, doctors may use a round cutting instrument. This procedure is called a punch biopsy.

Treatment of Kaposi Sarcoma

  • For people with one or two spots, various removal methods

  • For people with many spots, many affected areas, or affected lymph nodes, radiation therapy and chemotherapy

  • For the AIDS-associated type, antiretroviral medications and removal methods or antiretroviral medications and chemotherapy

Treatment varies depending on the type of sarcoma.

Classic Kaposi sarcoma

People who have many spots, many affected areas, or affected lymph nodes receive radiation therapy and chemotherapy. Kaposi sarcoma commonly returns and is difficult to completely cure.

People who have a more aggressive form that affects internal organs, but whose immune system is normal, often respond to interferon alfa or, more often, chemotherapy given by vein.

Iatrogenic Kaposi sarcoma

AIDS-associated Kaposi sarcoma

In people with AIDS, treatment with chemotherapy and radiation has not been very successful. However, intensive treatment with antiretroviral therapy

Endemic Kaposi sarcoma

The endemic type is difficult to treat. Doctors typically make sure people are comfortable and free of pain and that their symptoms are fully treated.

Non-epidemic Kaposi sarcoma

Spots that appear in people who have this type of sarcoma are treated the same way as in classic Kaposi sarcoma.

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

  1. American Cancer Society: Kaposi Sarcoma: Information about Kaposi sarcoma, including detection, prevention, treatment options, and other resources

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