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Kaposi sarcoma (KS) is a rare cancer that starts in the cells that line your blood vessels and lymph vessels. It causes abnormal growths. They often show up as red, purple or brown spots or lumps on your skin or inside your mouth.
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Symptoms and Signs
A type of soft tissue sarcoma, the most common sign of Kaposi sarcoma are the red, purplish or brown spots that appear on the skin. They are often flat or raised up like pimples. Kaposi sarcoma lesions usually do not hurt or itch. However, if they are on the legs or groin, they can block fluid flow and cause painful swelling. This disease most often shows up on the face or legs. But it can also grow in places you can’t see, like your lungs or stomach.
If this cancer spreads within the body, it can cause more serious problems. For example, if it grows in the lungs, it can make it harder to breathe or cause you to cough up blood. If these growths happen in the digestive tract, they can cause stomach pain. They might also cause diarrhea or internal bleeding that makes your stool (poop) look dark.
Causes and Risk Factors
Kaposi sarcoma is caused by a virus called human herpesvirus 8 (HHV-8), which is also known as KSHV. If a person gets this virus, it never goes away. However, most people who have the virus never get Kaposi sarcoma. It is mostly spread through saliva, though it can also be spread through sexual contact or blood, too. In order for it to spread, a person’s immune system must be weak.
There are four main types of Kaposi sarcoma:
- Epidemic Kaposi sarcoma: This is the most common type of Kaposi sarcoma in the U.S. and affects people who are living with HIV. It often causes spots on the skin or in the mouth and can spread to other organs if it is not treated.
- Classic Kaposi sarcoma: This type mostly affects older men of Mediterranean or Eastern European descent. It usually grows very slowly.
- Endemic Kaposi sarcoma: This type of Kaposi sarcoma is found in people living in parts of Africa where the virus is common.
- Iatrogenic Kaposi sarcoma: This type happens to people who have had an organ transplant and need to take certain medications. While these medicines help their body accept the new organ, they can weaken the immune system, which can allow the cancer to start growing.
Kaposi Sarcoma Care Team
At Fred Hutch, we offer comprehensive treatment from a team of experts who specialize in soft tissue sarcomas and bone cancers.
Learn more about sarcoma specialists at Fred Hutch.
Diagnosing Kaposi Sarcoma
Your physician will examine you, looking for lesions on your skin, in your mouth and/or other areas, such as the rectum. They also may order blood tests or imaging tests. The most important test is a biopsy, where your physician takes a tiny sample of a lesion so it can be examined in a lab. This helps them understand more about the unique features of your disease, as well as the stage.
Learn more about diagnosing sarcoma.
Treating Kaposi Sarcoma
If you have Kaposi sarcoma that is related to HIV, the most important treatment is antiretroviral therapy (ART), which strengthens your immune system so it can destroy the cancer.
A physician might also treat single skin spots with liquid nitrogen, surgery or radiation. If the cancer has spread, chemotherapy or immunotherapy might be the best treatment options. If the person being treated is a transplant patient, the physician may start by adjusting their medicine to help strengthen their immune system.
Learn more about treating sarcoma.
Prognosis and Survival
When physicians and scientists talk about cancer survival rates, they typically mean the percentage of people expected to survive their cancer for at least five years after being diagnosed. (The rate doesn’t include the risk of dying during that time for some other reason.) Overall, the relative five-year survival rate for Kaposi sarcoma in the U.S. is 75%. according to the SEER database from the National Cancer Institute.
This rate comes from looking at a large, varied group of people. The chance of surviving cancer at least five years can vary greatly from one person to another. It depends on many factors, like how far the cancer has spread. Your Fred Hutch care team can explain how statistics like survival rates might apply to you.
Learn more about prognosis and survival of sarcoma.