Kaposi Sarcoma

January 22, 2026

This page was reviewed under our medical and editorial policy by Lee Cranmer, M.D., Ph.D., professor, Department of Medical Oncology & Therapeutics Research, City of Hope^® Cancer Center Duarte.

Kaposi sarcoma is a very rare type of cancer, affecting only around 6 out of every 1 million people in the United States. This type of soft tissue sarcoma may be challenging to detect unless visible lesions appear on the skin or the inside of the mouth, nose or throat.

What Is Kaposi Sarcoma?

Sarcomas are cancers that occur in the soft tissues of the body, such as muscle, fat, tendons and the blood and lymph systems. Kaposi sarcoma is a cancer that arises in the cells that line the body’s blood vessels or lymph vessels.

The most common places Kaposi sarcoma is found are the skin and the inside of the mouth, but it may affect other parts of the body, including the lymph nodes, lungs and digestive system. In some cases, this condition causes lesions that become swollen and painful, often on the face or legs. Sometimes, Kaposi sarcoma may spread (metastasize) to other parts of the body. That being said, Kaposi sarcoma is known to be a systemic disease at the outset, meaning that it may be present throughout the body at the time of diagnosis.

Kaposi Sarcoma Causes and Risk Factors

Kaposi sarcoma was first recognized as a distinct disease in the 1870s by Dr. Kaposi, who was a dermatologist practicing in Vienna, Austria. Dr. Kaposi noted the distinct skin tumors that may develop in this condition among patients living in central Europe. He also recognized that the tumors in the skin did not represent all of the disease. Simply removing visible tumors would not cure the cancer. Although Dr. Kaposi could not have recognized the underlying cause of this disease, his observation represented a major advance in human understanding of cancer.

It was only at the end of the 20th Century that a specific cause of Kaposi sarcoma was recognized and identified. Kaposi sarcoma is caused by the human herpesvirus-8 (HH8), sometimes referred to as Kaposi sarcoma-associated herpesvirus (KSHV). Certain groups of people are more likely to develop Kaposi sarcoma if they are infected with HH8. These include:

• People living with HIV (human immunodeficiency virus)
• People who undergo an organ transplant and must taking certain drugs that weaken the immune system
• Younger men in sub-Saharan Africa
• Older men with Eastern European or Mediterranean heritage

The form of Kaposi sarcoma recognized by Dr. Kaposi is termed “endemic” Kaposi sarcoma. This occurs within populations without a specific inciting factor. In the 1980s, a higher frequency of Kaposi sarcoma was first noted in younger men in cities in the United States and Europe. This was one of the first signs of the HIV pandemic, and was later termed “epidemic” Kaposi sarcoma, to distinguish it from the more typical form of the disease previously seen. The suppression of immune system function caused by the HIV virus allowed the virus that causes Kaposi sarcoma to become active and cause this type of cancer. The progress in treating HIV and its associated conditions, including Kaposi sarcoma, have been a major advance in medicine, which has benefited both those with HIV and those with the classical endemic form of Kaposi sarcoma.

Kaposi Sarcoma Symptoms and Signs

The symptoms of Kaposi sarcoma may differ, depending on where the condition begins and what type of Kaposi sarcoma someone has.

Kaposi sarcoma that develops on the skin may cause small, flat lesions that are not initially painful. They are often brown or dark purple, like a bruise. Eventually, they may swell or begin to feel sore, especially if the lesions are blocking a lymph node.

Kaposi sarcoma that develops inside the body often affects the liver, spleen, digestive tract and lungs. While it may also cause lesions, it is more common that people experience symptoms related to the location of the cancer, for instance, problems breathing caused by lung Kaposi sarcoma or internal bleeding related to Kaposi sarcoma of the digestive system.

Tests for Diagnosing

Cancer doctors may use a wide range of tests to diagnose Kaposi sarcoma. Which tests they recommend will depend on the kinds of symptoms someone is experiencing and where in the body these symptoms appear

A physical exam: This may be the first step in diagnosing Kaposi sarcoma, especially if a patient has visible lesions on the surface of the skin. Doctors may also examine the rectum and anus for lesions.

A biopsy: This procedure removes a small sample of tissue that is examined under a microscope for cancer cells. A punch biopsy, which takes a small circle of tissue, is the most common option for smaller skin lesions, while an excisional biopsy may be used to remove an entire lesion.

A chest X-ray or bronchoscopy: These may be used to screen for Kaposi sarcoma of the lung. An X-ray may detect something unusual in the lung that needs further investigation. A bronchoscopy is a procedure performed under anesthesia, in which a doctor inserts a narrow, flexible tube with a light and a camera into the airways via the mouth.

Gastrointestinal endoscopy: Such procedures use a thin tube with a light and camera at the end to look at the inside of the digestive tract. For patients with symptoms affecting the digestive system, doctors may perform a colonoscopy to look at the large intestine or an upper endoscopy to examine the windpipe, stomach and some of the small intestine.

Kaposi Sarcoma Stages

After diagnosis, the care team assesses the size and spread of a patient’s cancer in a process called staging. Unlike most cancers, Kaposi sarcoma does not have an official staging system. However, because it often affects people living with HIV/AIDS, cancer experts use the AIDS Clinical Trials Group (or ACTG) system to assess the extent of Kaposi sarcoma. The ACTG system takes into account:

• The size of the tumor or tumors (T)
• To what degree a patient’s immune system (I) is weakened, based on the results of a test to check CD4 immune cell levels
• The degree to which a patient has systemic illness (S), and whether it is HIV or cancer

Each of these is given a value of either 0 or 1, with 0 meaning “good risk” (i.e., a better prognosis) and 1 meaning “bad risk” (i.e., a worse prognosis). This staging system helps cancer care providers determine the next steps in creating a personalized treatment plan for Kaposi sarcoma.

Another simple way in which Kaposi sarcoma may be staged is based on whether it requires general treatment, which would generally be the case in poor risk disease above, or when the disease is very widespread in the body. Some people with Kaposi sarcoma have a very limited number of tumors, which may be very small and do not require specific treatment or only require very limited treatment for cosmetic purposes.

Types of Kaposi Sarcoma

There are four distinct types of Kaposi sarcoma.

Classic Kaposi sarcoma: This is the type of disease originally identified by Dr. Kaposi. It primarily affects men with Mediterranean or Central/Eastern European heritage. It is slower growing and generally only involves the skin, most frequently on the legs.

Endemic Kaposi sarcoma: This type affects people in certain parts of sub-Saharan Africa, where the HH8 virus is more common. It tends to be a faster-growing type of the disease.

Immune deficiency-related Kaposi sarcoma: This type affects people with certain forms of immune deficiency. This means that their immune system does not work as well as normal. This allows the virus that causes Kaposi sarcoma to grow unchecked by the immune system.

Causes of this may include HIV/AIDS, suppressed immunity from medicines for organ transplants, or suppressed immunity from cancer treatment. This form of Kaposi sarcoma tends to grow faster than some other types. It also may affect internal organs more frequently.

Kaposi Sarcoma Treatment

Doctors who treat Kaposi sarcoma may recommend one or several treatment options, depending on a variety of factors, such as the type of Kaposi sarcoma a patient has, whether he or she has an immune deficiency, such as an organ transplant or HIV/AIDS, and the extent of the cancer.

Restoration of Immune Function

For those with Kaposi sarcoma associated with impaired immunity, a key treatment is to attempt to restore the function of the immune system, if possible. This depends on what the cause of the immune dysfunction is and how much normal immunity may be restored.

For people who have had organ transplants, for example, they generally require lifelong suppression of their immune system in order to retain the function of their transplanted organ. It may be possible to lower the amount of immune suppressing medicines or change to different immune suppressing medicines in order to allow some restoration of immunity to control the virus causing Kaposi sarcoma.

For people with HIV/AIDS, highly active antiretroviral therapy (HAART) is a treatment option that combines several medications to treat HIV. This may help restore immune function, allowing the immune system to control the virus causing Kaposi sarcoma. In some cases, this may be the only treatment required to control Kaposi sarcoma. In other patients, HAART is combined with other treatments to control Kaposi sarcoma.

Surgery and Other Destructive Treatments for Kaposi Sarcoma

As noted earlier, Kaposi sarcoma is a systemic disease. This means that the lesions or tumors caused by the disease do not represent the whole disease in a patient. Therefore, simply removing the visible tumors may not cure the disease. However, it may be possible to use local therapies to treat tumors that are visible or are otherwise causing symptoms. 

These treatments may include surgery to remove Kaposi sarcoma lesions from the skin. They may also involve procedures which otherwise destroy the tumors, such as freezing (cryosurgery), burning the lesions (electrodessication), or injecting the lesions with chemotherapy or immune-boosting medicines to treat individual tumors. While these will not cure the disease, they may provide significant relief from symptoms caused by the tumors.

Radiation Therapy

Certain radiation therapy techniques may be used to treat Kaposi sarcoma lesions or tumors. Radiation therapy is targeted at a specific area of the body, with the goal of killing cancer cells or slowing down their growth.

Chemotherapy and Immunotherapy

Chemotherapy uses drugs to target and kill cancer cells. As noted above, these may sometimes be injected directly into a tumor to treat it. In other cases, the disease is more extensive and treating individual tumors will not be effective enough. In those circumstances, giving a medicine intravenously, in which it circulates throughout the body, may be an effective approach to treatment. 

Kaposi sarcoma may respond very well to a number of different types of chemotherapy medicines. Such treatment may also be administered along with treatments intended to restore the function of the patient’s immune system. Sometimes, chemotherapy is used as a “bridge treatment” to control Kaposi sarcoma until the immune system may do so on its own.

New medicines known as immunotherapy are being explored as potential treatments for Kaposi sarcoma. These medicines attempt to direct the immune system to control the disease. Initial results are promising and such therapy will likely play a more important role in the future in helping patients with Kaposi sarcoma.

Who Treats Kaposi Sarcoma?

Patients with Kaposi sarcoma receive treatment from a multidisciplinary team of clinical providers, including:

• Infectious disease specialists, who are highly experienced at managing and treating conditions like HIV/AIDS
• Transplant medicine specialists, with expertise in the use of immune suppressing medicines in patients who have had bone marrow, stem cell, or organ transplants.
• Medical oncologists with expertise in the latest cancer therapies
• Dermatologists, who specialize in treating skin conditions
• Surgical oncologists, who are experts in removing soft tissue tumors
• Radiation oncologists specializing in the latest innovative radiation therapies
• Pathologists with expertise in evaluating test results
• Specialized pharmacies, which supply medications to treat the condition
• Supportive care providers, who help manage the physical and emotional side effects of treatment

Kaposi Sarcoma Survival Rate

The average five-year relative survival rate for Kaposi sarcoma is approximately 75%, which means that people diagnosed with the condition are 75% as likely to survive more than five years after diagnosis as people who do not have this type of cancer.

Survival rates are further broken down based on how far the cancer has spread, as listed below.

Localized Kaposi sarcoma: If the cancer cells are confined to one area, the five-year relative survival rate is 84%.

Regional Kaposi sarcoma: If the cancer cells have spread to nearby tissues or lymph nodes, the five-year relative survival rate is 64%.

Distant Kaposi sarcoma: If the cancer cells have spread to distant organs or tissues, the five-year relative survival rate is 50%.

Most patients with Kaposi sarcoma have other medical conditions contributing to their having Kaposi sarcoma and also affecting their health. In such patients, treating both Kaposi sarcoma and other contributing medical conditions is critical for optimal outcomes. Always speak with the care team to receive a personalized prognosis based on the patient’s overall health, sarcoma type and other factors.