What is soft tissue sarcoma?
Soft tissue sarcoma is a type of cancer that forms in the soft tissues of the body. Soft tissue is the name for all the supporting tissues in the body, apart from the bones, including fat, muscle, nerves, tendons, deep skin tissue, lymph vessels, blood vessels and tissue around joints. These tissues are called connective tissue, as they support and connect all the organs and structures of the body.
A soft tissue sarcoma is a rare type of cancer that generally forms as a painless lump (tumour) in any one of these soft tissues. It can develop anywhere in the body, but most commonly in the thigh, shoulder, arm, pelvis and abdomen. Malignant (cancerous) tumours have the potential to spread to other parts of the body through the blood stream or lymph vessels and form another tumour at a new site. This new tumour is known as secondary cancer or metastasis.
Your guide to best cancer care
A lot can happen in a hurry when you’re diagnosed with cancer. The guide to best cancer care for sarcoma (bone and soft tissue tumours) can help you make sense of what should happen. It will help you with what questions to ask your health professionals to make sure you receive the best care at every step.
Read the guide
Types of soft tissue sarcoma
There are more than 70 types of soft tissue sarcoma. They are named after the abnormal cells that make up the sarcoma.
The most common type in adults is undifferentiated pleomorphic sarcoma (UPS), which is made up of many abnormal spindle-shaped cells. It is aggressive so it often returns or spreads after treatment. Other types of soft tissue sarcoma include:
- Liposarcoma from fat cells
- Leiomyosarcoma and rhabdomyosarcoma from muscle tissues
- Angiosarcoma from blood and lymph vessels
- Malignant peripheral nerve sheath tumour (MPNST or PNST) from the lining of nerve cells
- Gastro-intestinal stromal sarcoma (GIST) from nerve cells in the gut (treated differently from other types of soft tissue sarcoma)
- Stromal sarcoma from supporting tissues
- Kaposi sarcoma from skin cells.
Children and young adults
- Rhabdomyosarcoma from muscle cells
- Ewing sarcoma (may also start in the bone)
- Synovial sarcoma from cells around joints and tendons.
How common is soft tissue sarcoma?
Soft tissue sarcoma is rare. Around 1600 Australians are diagnosed with a soft tissue sarcoma each year (about 6 cases per 100,000 people). It is slightly more likely to be diagnosed in men than women. While soft tissue sarcoma can develop at any age, it is more likely to be found in people over 55 years old.
Learn more about rare cancer
The causes of most sarcomas are unknown. However, there are several risk factors, including:
There is a very small risk for people who have had radiation therapy to treat other types of cancer. The risk is higher for people who had high doses of radiation therapy at a very young age. Most people who have had radiation therapy in the past will not develop soft tissue sarcoma.
Some rare, inherited conditions can put people more at risk of soft tissue sarcoma. These conditions include von Recklinghausen disease (also known as neurofibromatosis), Li–Fraumeni syndrome and retinoblastoma.
Most people know if one of these very rare conditions runs in their family, and if so, that they may pass it to their children. If you do not know of this condition in your family, then it is very unlikely that it is present.
A small number of people develop sarcoma due to genetic changes that happen during their lifetime, rather than inheriting a faulty gene.
Some sarcomas may be linked to being exposed to chemicals including vinyl chloride (used to make plastic) and some high-dose herbicides (weedkillers).
Long-term lymphoedema in the body, for example in the legs or arms (swelling from a build-up of lymph fluid) has been linked with angiosarcoma.
Soft tissue sarcoma usually doesn’t cause symptoms in its early stages. As it grows over a period of months, you may develop a painless lump, which may cause pain as it grows and presses on nerves and muscles.
Other symptoms will depend on where in the body the sarcoma is. Sometimes a soft tissue sarcoma may be mistaken for a benign fatty lump (lipoma) or bruise (haematoma). This can delay tests that would help make the right diagnosis.
Most people who develop a painless lump do not have a sarcoma. However, you should see your doctor if you notice the lump is getting bigger, is the size of a golf ball or larger, or is painful or tender.
If your doctor thinks that you may have a soft tissue sarcoma, they will take your medical history, perform a physical examination (including feeling any lumps) and carry out certain tests. These tests are needed to rule out other conditions.
If the results suggest that you may have sarcoma, your doctor will refer you to a specialist who will carry out more tests, including:
- Blood tests – including a full blood count to measure your white blood cells, red blood cells and platelets.
- X-rays – a painless scan of your chest to check your lungs for signs of cancer.
- CT or MRI scans – special painless machines are used to scan and create pictures of the inside of your body.
- PET scan – you will be injected with a small amount of radioactive glucose (sugar) solution to help cancer cells show up brighter on the scan.
- Biopsy – removal of some tissue from the affected area for examination under a microscope.
Finding a sarcoma specialist
The Australia and New Zealand Sarcoma Association (ANZSA) can be contacted for a directory of specialists in sarcoma care and treatment. Rare Cancers Australia also have a useful directory of health professionals and cancer services across Australia.
Understanding Soft Tissue Sarcoma
Download our Understanding Soft Tissue Sarcoma fact sheet to learn more.Download now
Expert content reviewers:
Dr Susie Bae, Medical Oncologist, Peter MacCallum Cancer Centre, VIC; Tony Bice, Consumer; Dr Denise Caruso, CEO Australian and New Zealand Sarcoma Association, VIC; Emma Gardner, Nurse Coordinator, Bone and Soft Tissue Unit, Peter MacCallum Cancer Centre, VIC; Jonathan Granek, Consumer; Thelma Lobb, Consumer.
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The information on this webpage was adapted from Understanding Soft Tissue Sarcoma - A guide for people affected by cancer (2021 edition). This webpage was last updated in June 2021.