Soft Tissue Sarcoma

What is soft tissue sarcoma?

Soft tissue sarcoma is a rare cancer that forms in the soft tissues of the body.

Soft tissues connect, surround and support your body parts and organs. They include blood vessels, fat, muscles, nerves and tendons.

Soft tissue sarcoma can occur anywhere in the body but is most commonly found in the arms, legs and abdomen.

Types of soft tissue sarcoma

There are more than 50 types of soft tissue sarcoma. Some affect children more than adults. The different types of soft tissue sarcomas include:

• Abdominal sarcoma, which can grow inside the gastrointestinal tract, abdominal wall or area behind organs in the abdomen (retroperitoneum).

• Angiosarcoma, or cancer that forms in the linings of the blood vessels and lymph vessels.

• Dermatofibrosarcoma protuberans, a type of skin cancer which originates from the connective tissues in the skin.

• Desmoid tumour, which develops in the connective tissues and are most commonly found in the abdomen, shoulders, upper arms and thighs.

• Desmoplastic small round cell tumours, that often begin in the abdomen.

• Epithelioid sarcoma, which starts in the soft tissue under the skin of a finger, hand, forearm, lower leg or foot, etc.

• Ewing sarcoma, which can affect bones and soft tissues around the bones. Ewing sarcoma is commonly found in the hip bones, ribs or long bones in the body (e.g. shin and thigh bones).

• Ganglioneuroblastomas, which are tumours that develop in the nerve tissue. They occur mainly in children below 5 years old.

• Gastrointestinal stromal tumours (GISTs), which affect the connective tissues supporting organs of the digestive system, especially in the stomach and small intestines.

• Hemangiopericytoma, a type of cancer that develops in the blood vessels.

• Kaposi's sarcoma which forms in the lining of the blood and lymph vessels. The tumours typically appear as painless purplish spots on the legs, feet or face. They can also be found in the genital area, mouth or lymph nodes.

• Liposarcoma, which forms in fat tissues.

• Malignant peripheral nerve sheath tumours, which are cancers that start in the lining of the nerves from the spinal cord to the body.

• Myxofibrosarcoma, a type of cancer that forms in the connective tissues. It is more common in the arms and legs.

• Rhabdomyosarcoma, a cancer that forms in skeletal muscle tissues around the head, neck, arms and legs, or hollow organs such as bladder, testes, vagina and uterus. Rhabdomyosarcoma affects children more than adults.

• Solitary fibrous tumour, which develops in the lining around the outside of the lungs, or in the head and neck, breast, kidney, prostate, spinal cord, and other parts of the body.

• Synovial sarcoma, a cancer that tends to develop near large joints, particularly the knee. It can also be found in arms, legs and throat.

• Undifferentiated pleomorphic sarcoma, a cancer that usually develops in the soft tissues of arms or legs, or less frequently, in the area behind the abdominal organs.

• Uterine sarcoma, which forms in the uterus.

What are the symptoms of soft tissue sarcoma?

Soft tissue sarcoma may not cause any symptoms in the early stages.

As the tumour grows, you may start to notice:

• Swelling, or a lump under your skin.
• Pain in your abdomen if the swelling is in the tummy. You may also keep feeling full or experience constipation.
• Coughing or feeling breathless if the swelling occurs near your lungs.

If you have a lump, especially one that grows bigger over time or becomes painful, have it checked by your doctor.

What causes soft tissue sarcoma?

Causes of soft tissue sarcoma are usually unknown.

One exception is Kaposi's sarcoma, which is caused by a human herpes virus 8 (HHV-8) infection. Persons with a weakened immune system (e.g. those with HIV infections) who have been infected with the HHV-8 are more prone to developing Kaposi's sarcoma.

What are the risk factors for soft tissue sarcoma?

These risk factors are associated with a higher chance of developing soft tissue sarcoma:

• Age. Although soft tissue sarcoma can happen at any age and affect even very young children, it is more common among middle-aged adults or the elderly. The risk increases with age.

• Genes. Some genetic factors are linked to a higher risk of developing soft tissue sarcoma.

• Radiation exposure. Some patients who have undergone radiation therapy for a primary cancer may develop soft tissue sarcoma subsequently. This usually happens many years after the radiation exposure.

• Toxin exposure. Prolonged exposure to certain chemicals such as vinyl chloride, dioxins, arsenic and phenoxyacetic herbicides has been associated with a higher risk of developing soft tissue sarcoma.