Kaposi sarcoma

Kaposi sarcoma is a cancer that develops in the walls of blood vessels and lymph vessels (the channels supporting the immune system). These tumor-forming soft tissue sarcomas are often tied to the human immunodeficiency virus (HIV). They’re found most often in the skin—making them an unusual skin cancer—or the linings of the mouth, nose, and anus.

Sometimes, Kaposi sarcoma is more disseminated (widespread) in the body, making it harder to treat and often posing a greater health threat. Unlike many other cancers, it doesn’t necessarily metastasize (spread) to these additional sites in the body from a single tumor. Instead, without treatment, tumors can quickly develop in multiple places in the body, including the lymph nodes, lungs, liver, spleen, and gastrointestinal (GI) tract.

Kaposi sarcoma is a rare cancer—thanks to the development of drugs to treat HIV and AIDS, the number of Kaposi sarcoma cases has fallen in the U.S. Each year, roughly six people per million are now diagnosed with it. Globally, the total annual figure is about 34,000.

At Penn Medicine, Kaposi sarcoma is cared for by in partnership by the Sarcoma Program and the HIV Oncology Program at the Abramson Cancer Center. Both programs’ teams are among the nation’s most experienced at providing Kaposi sarcoma care. They’ve treated the disease for decades—since the early days of the HIV-AIDS epidemic.

Doctors and researchers divide Kaposi sarcoma into four types:

• Epidemic Kaposi sarcoma: This type of Kaposi sarcoma is the most common. Because HIV infections make people more likely to also develop HHV-8, epidemic Kaposi sarcoma is considered connected to the HIV epidemic. Developing a Kaposi sarcoma is one of the signs that HIV infection has turned into AIDS. Epidemic sarcoma also has the potential to develop widely across the body. Fortunately, effective drug therapy for HIV has resulted in fewer cases of Kaposi sarcoma. If you do develop Kaposi sarcoma, HIV drugs can stop it from progressing.
• Acquired Kaposi sarcoma: Some people with HHV-8 develop Kaposi sarcoma because their immune systems are weakened due to factors including autoimmune disease or immune-suppressing drugs taken after organ transplant. Roughly 1 in 200 U.S. transplant patients develop Kaposi sarcoma. It usually is limited to the skin but sometimes becomes widespread.
• Classic Kaposi sarcoma: This form is mainly found in older people of Mediterranean, Eastern European, or Middle Eastern descent. It is more common in men than women. Researchers believe these people have genetic changes that make them more vulnerable to HHV-8. As they age, their immune systems also naturally grow weaker, raising Kaposi sarcoma risk. Classic-type tumors tend to grow less quickly and widespread disease is less likely.
• Endemic Kaposi sarcoma: Most cases of endemic Kaposi sarcoma are found in Africa, where HHV-8 infection rates are much higher and other common diseases weaken the immune system. It can affect children and adults, mostly under 40 years old. Endemic Kaposi sarcoma typically does not grow beyond the skin.

Kaposi sarcoma typically starts as small, flat patches on the skin or inside the mouth. These patches may be red, purple, pink, brown, black, or blue and look like bruises. They don’t usually cause pain at first but can turn into bumps as they grow and may form open wounds.

More widespread Kaposi sarcoma can cause:

• Bleeding or blockage in the digestive tract
• Breathing trouble
• Chest pain
• Diarrhea
• Fever
• Coughing up blood
• Gastrointestinal pain
• Lymphedema, or painful swelling in certain tissues
• Nausea and vomiting
• Severe sweating while sleeping
• Unintended weight loss

Unlike many other soft tissue sarcomas, doctors do know the cause of Kaposi sarcoma—a virus called human herpesvirus 8 (HHV-8). The virus spreads through sex, saliva, and childbirth. Researchers believe the virus changes instructions for how certain cells grow, making them grow out of control and form tumors.

HHV-8 infections are uncommon in the U.S. and people with the virus don’t necessarily develop Kaposi sarcoma. The cancer only seems to form when people have a weakened immune system or have inherited genetic changes that make them more vulnerable.

At Penn Medicine, diagnosis of Kaposi sarcoma starts by asking about symptoms and examining any places it can start, including the skin, mouth, nose, and anus. Our team will also check your lymph nodes.

To confirm a diagnosis and determine the extent of the disease, our doctors may:

• Order blood tests to check the immune system and look for HIV, if it has not yet been diagnosed
• Take a biopsy (tissue sample) of any visible lesions
• Arrange imaging such as computed tomography (CT) or positron emission tomography (PET) to examine organs
• Perform minimally invasive procedures that thread a camera and light toward the lungs or GI tract, with the possibility of removing tissue samples

Kaposi sarcoma is treatable, but therapy may not always cure the cancer and it could recur (return). The results of sarcoma treatment depend on the extent of cancer, the strength of the immune system, and whether you have any HIV-related medical conditions.

For epidemic Kaposi sarcoma, our treatment starts with drugs designed to destroy HIV, if they’ve not already been prescribed. These drugs can cause tumors to shrink and at times provide all the treatment needed.

Other Kaposi sarcoma treatments our team may recommend include:

• Surgery: Our doctors may consider removing Kaposi sarcoma when tumors are small, limited in number, and visible. However, tumors can also grow back larger, so sarcoma surgery is often not the first recommendation for treatment.
• Radiation therapy: When the number of tumors is limited, radiation therapy may provide a treatment option for Kaposi sarcoma.
• Chemotherapy: Unlike some other soft tissue sarcomas, Kaposi sarcoma tends to respond well to anti-cancer drugs, and people experience limited side effects. We may inject chemotherapy into visible tumors or apply it as a topical gel. If cancer is more widespread, they may deliver chemotherapy through intravenous (IV) lines.
• Cryotherapy: Our medical team may inject liquid nitrogen to visible tumors, using extreme cold to destroy cancerous tissue.
• Clinical trials: Researchers are exploring additional ways to treat Kaposi sarcoma, particularly when disease is widespread. They are also interested in treating HHV-8 directly. Targeted therapy—drugs aimed at growth pathways in cells—represents one area of research. Another is immunotherapy, which harnesses the immune system.

At Penn Medicine, we offer a full range of the latest treatments for Kaposi sarcoma, with expert specialists coordinating your care.