Soft tissue sarcoma types

There are different types of soft tissue sarcoma. We describe the most common types in this section. Your doctor or specialist nurse can tell you more about which type you have.

A sarcoma is not named after the part of the body where it started. Instead, it is named after the type of cell it looks like.

Some sarcoma starts from very early, undeveloped cells called stem cells. As they grow, they start to look like a particular tissue.

There are 2 types of muscle tissue in the body, called smooth and skeletal muscle.

Smooth muscle sarcoma

Leiomyosarcoma (LMS) is one of the more common types of sarcoma. It develops in smooth muscle. Smooth muscle makes up the walls of internal organs, such as the womb (uterus), stomach, bowel and blood vessels. The muscle makes these organs contract (shorten) without our control.

This sarcoma can develop anywhere in the body. It is most common in the tummy, retroperitoneum and pelvic area. Sometimes it starts in the deep, soft tissues of the arms or legs.Leiomyosarcoma usually develops in people over 50.

Skeletal muscle sarcoma

Rhabdomyosarcoma (RMS) develops in skeletal muscles. These are the active muscles in our arms and legs, and other parts of the body.

Skeletal muscle sarcoma is most common in the head and neck. But it can also develop in organs such as the bladder, vagina or arms or legs. Rhabdomyosarcoma is most common in children.

Fibrous tissues join the inner structures of the body. For example, they join muscles to bones. This tissue is made up of cells called fibrocytes. A sarcoma of the fibrous tissue is called a fibroblastic sarcoma. There are different types:

Synovial sarcoma

This tumour can develop anywhere in the body. It most commonly affects the arms and legs. It is usually diagnosed in people aged 15 to 35 but can develop at any age, including childhood.

Gastrointestinal stromal tumour (GIST)

This is the most common type of soft tissue sarcoma to develop in the digestive system. The digestive system is often called the gastrointestinal (GI) tract. It is made up of the gullet, stomach and bowel. GISTs start in nerve cells that make the muscles of the digestive system tighten and relax. They behave differently from other types of sarcoma and are treated differently.

Kaposi’s sarcoma (KS)

Kaposi’s sarcoma develops differently from other sarcomas. It starts from cells in the skin. Coloured patches or lumps can develop in the skin or mouth. Lymph nodes or internal organs such as the lungs, liver or spleen are rarely affected. It is linked with human herpes virus (HHV8).

There are different types of KS. Certain types can affect people with a weakened immune system. This includes people with HIV and people who have had an organ transplant. Other types of KS can happen in parts of the world where human herpes virus (HHV8) is more common.

Kaposi’s sarcoma is treated differently from other types of soft tissue sarcoma.

Soft tissue Ewing sarcoma

Ewing sarcoma is a rare cancer that usually develops in the bones. Sometimes Ewing sarcoma starts in the soft tissues of the body. This is called soft tissue Ewing sarcoma. Ewing sarcoma is most common in teenagers.

Soft tissue Ewing sarcoma behaves differently to other types of soft tissue sarcoma. It is treated in the same way as a Ewing sarcoma that starts in the bone.

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