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Types of soft tissue sarcoma

Kaposi's sarcoma (Kaposi sarcoma cancer)

Kaposi's sarcoma (KS) develops from cells called endothelial cells, which line the blood and . KS is a rare type of soft tissue sarcoma. A soft tissue sarcoma is a type of cancer.

KS is most commonly found on the skin, but it can also affect the inside of the body, such as the:

  • bowel

KS growths are also called or

KS develops in a different way from other types of cancer. Most cancers begin in one place in the body and may then spread to other parts of the body (metastasise). KS can start in several areas of the body at the same time.

Causes of Kaposi’s sarcoma

A main cause of KS is a called the human herpesvirus 8 (HHV8), also known as Kaposi’s sarcoma associated herpesvirus (KSHV). The virus infects the cells and it is thought that this causes them to become cancerous.

HHV8 is mostly a sexually transmitted virus and is a common . It can also pass in blood between drug users who share needles.

Not everyone infected with HHV8 gets KS. It is thought that there are other factors involved. Scientists agree that having a weakened or certain types of infection along with HHV8, also play a part in a person developing KS.

Read about risks and causes of soft tissue sarcoma

Signs and symptoms of Kaposi's sarcoma

The signs and symptoms are different. They depend on whether you have external KS on the skin or KS inside the body. Lesions on the skin are more common than internal lesions inside the body.

Kaposi's sarcoma of the skin

Lesions on the skin usually start out very small and flat. They do not cause any pain or itching and seem harmless. They look like a bruise but do not lose their colour when pressed, as a bruise does.

As they grow, they might start to stick up above the surrounding skin and grow into each other. The lesions might be in different colours such as brown, blue, red or deep purple.

Occasionally, the lesions form  that can become ulcerated and may bleed. The lumps are associated with painful swelling (oedema).

KS in the skin might grow very slowly and show no changes for a few months. But some grow more quickly, with new areas appearing weekly.

Internal Kaposi's sarcoma

Internal KS lesions can grow in the lymph nodes and body organs, such as the: 

  • lungs

  • liver

  • spleen

The symptoms you have depend on which organs are affected.

The most common type of KS is related to AIDS. In AIDS related KS, it is common for disease to be in the lymph nodes. KS cells can block the flow of  through the . This build up of fluid can cause swelling in the arms or legs. This is called lymphoedema.

Lymphoedema can be very painful and uncomfortable. Unfortunately, there is no cure for this condition. But treatment can help to control and relieve it. The earlier this is picked up and treated, the easier it is to control. It is important to let your doctor know if you have any swelling that you think might be lymphoedema.

Read more about lymphoedema

Types of Kaposi's sarcoma

There are four types of Kaposi's sarcoma:

  • classic KS

  • endemic or African KS

  • transplant related KS

  • AIDS related KS

Classic Kaposi's sarcoma

This type of KS is very rare and is only found on the skin, mainly on the lower legs and feet. It is most common in older men of Mediterranean or Central and Eastern European origin. It can be a slow growing cancer and does not usually cause any problems apart from the appearance of the lesions.

You might not need treatment until the KS lesions are large and in very visible areas of the body.

Endemic or African Kaposi's sarcoma

This type of KS is found in parts of Africa where HHV8 infection is common. It is faster growing than classic KS.

It affects both adults and children.

Transplant related Kaposi's sarcoma

This type of KS is very rare and is most common in people with lowered immunity. This includes people who have had a stem cell or organ transplant. These people need to take drugs to stop their bodies from rejecting the new organ or stem cells. These drugs suppress the immune system. They are called immunosuppressive drugs or immunosuppressants.

AIDS related Kaposi's sarcoma

KS is the most common type of tumour in people infected with HIV. It tends to grow faster than the other types. People with AIDS have a weakened immune system. This increases the risk of developing KS.

Tests to diagnose Kaposi's sarcoma

Kaposi's sarcoma (KS) is usually diagnosed with a . A specialist doctor ( ) then looks at the cells under a microscope. 

The way you have the biopsy depends on where in your body the lesion is.

Skin lesions 

You usually have a biopsy with a if the lesion is on the skin. A local anaesthetic numbs the area.  

Lesions in the lung 

You might have a to collect a biopsy from a lung lesion. 

Lesions in the digestive system

You might have an or to biopsy lesions in the digestive system. 

Other tests might include:

  • a

  • an

  • a

  • a

  • a test to check for blood in the stool

Read more about tests

Treatment for Kaposi’s sarcoma

Your treatment depends on:

  • the type of KS

  • the size and location of the lesions

  • how severe it is

  • your general health

Treatment options for all types of KS might include one or more of the following, depending on whether the lesions are or widespread:

  • freezing the area with liquid nitrogen (cryotherapy)

  • laser treatment

  • removing the lesions with a small operation

  • radiotherapy to the lesions

  • creams applied to the lesions (topical therapy)

  • chemotherapy into your bloodstream

  • an called interferon alfa

Additional treatments for transplant related KS include stopping an immunosuppressant drug or changing the dose. Or using an immunosuppressant drug called sirolimus that prevents rejection of a kidney after a kidney transplant

An additional treatment for AIDS related KS includes antiretroviral therapy. This works by stopping HIV from reproducing. It can reduce your levels of HIV and keeps your immune system healthy. 

Read about treatment for soft tissue sarcoma

Treatment for advanced KS

You usually have chemotherapy if you have widespread KS lesions. Treatment at this stage is palliative. This means it is used to treat symptoms rather than offer a cure. You usually have 2 or more of these drugs:

  • doxorubicin liposomal

  • daunorubicin liposomal

  • paclitaxel

  • vinorelbine

  • etoposide

  • gemcitabine

Read about the different chemotherapy drugs

You might also have treatment as part of a clinical trial. Speak to your doctor if you’d like to know more about trials for Kaposi’s sarcoma.

Find out more about clinical trials

Coping

Coping with a diagnosis of a rare cancer can be especially difficult. Knowing more about your sarcoma and its treatment can make it easier. It can help you to make decisions and cope with what happens.

Sarcoma UK has support and information for people affected by soft tissue and bone sarcoma.

Visit the Sarcoma UK website

The Rare Cancer Alliance offer support and information to people with rare cancers.

Visit the Rare Cancer Alliance website

Talking to other people who have the same thing can also help.

Our discussion forum Cancer Chat is a place for anyone affected by cancer. You can share experiences, stories and information with other people who know what you are going through.

Visit Cancer Chat

Last reviewed: 15 Aug 2024

Next review due: 15 Aug 2027

Types of soft tissue sarcoma

The type of soft tissue sarcoma you have tells you the type of cell that the cancer started in. Knowing this helps your doctor decide which treatment you need.

Treatment for soft tissue sarcoma

The main treatment for soft tissue sarcoma is surgery. You may also have radiotherapy treatment to reduce the symptoms and help you feel better. A team of doctors and other professionals discuss the best treatment and care for you.

Living with soft tissue sarcoma

Lots of advice and support are available to help you cope with soft tissue sarcoma and its treatment.

Preparing for treatment and life afterwards (prehabilitation)

There are things you can do to help you feel more in control of your health when preparing for treatment. This is called prehabilitation or prehab.

Soft tissue sarcoma main page

Soft tissue sarcomas are cancers that develop in the supporting tissues of the body. These include tissues such as the muscle, nerves, fat and blood vessels.

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