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 drugs or interferon alfa.
(See also Overview of Skin Cancer.)
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 four 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 Italian, Eastern European, or 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.
Immunosuppressive Kaposi sarcoma: This type affects people whose immune system is weakened by immunosuppressants given after organ transplantation.
AIDS-associated Kaposi sarcoma (epidemic Kaposi sarcoma): This type affects people with AIDS (which accounts for most of the cases in the United States).
Kaposi sarcoma usually appears as purple, pink, or red spots or bumps on the skin. The cancer may grow to several inches or more as a blue-violet to black, flat or slightly raised area. 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.
Older (over age 60) men 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 other groups, Kaposi sarcoma is more aggressive. Similar-appearing spots develop, but they are often multiple and may occur anywhere on the body.
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.
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.
Doctors usually recognize Kaposi sarcoma by its appearance. 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.
Older men with slow-growing Kaposi sarcoma in one or two spots may have the tumors removed surgically, with extreme cold (cryosurgery), or with an electrical current (electrocoagulation). Imiquimod cream or injections of vinblastine or interferon alfa may also be used to remove the spots. Some people with very few spots and no other symptoms may choose to receive no treatment unless the condition spreads.
People who have a more aggressive form, but whose immune system is normal, often respond to interferon alfa or chemotherapy drugs.
In people taking immunosuppressants, the tumors sometimes disappear when immunosuppressants are stopped. However, if these drugs must be continued because of the person’s underlying condition, the immunosuppressants are reduced. If immunosuppressants cannot be reduced, surgery, chemotherapy, and radiation therapy are used. People may also be given sirolimus. These treatment methods are less successful than in people with a healthy immune system.
In people with AIDS, treatment with chemotherapy and radiation has not been very successful. However, intensive treatment with antiretroviral therapy (ART) helps, provided that people’s immune system improves because of the treatment. People with the AIDS-associated type may also be given interferon alfa or chemotherapy drugs (such as doxorubicin or paclitaxel) by vein. In general, treating Kaposi sarcoma does not prolong the lives of most people with AIDS.