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Soft Tissue Sarcomas

This information should not be used for self-diagnosis or in place of a qualified physician's care.

Revised Nov 2020

The basics

Soft tissue connects, supports and surrounds the organs and structures within the body.

Soft tissue consists of muscles, joints, fat, blood vessels, tendons, synovial tissues (tissues around joints) and nerves.

Soft tissue sarcomas form in the soft tissues anywhere in the body but are most commonly found in the arms and legs.

What causes it and who gets it?

Listed below are some of the known risk factors for this cancer. Not all of the risk factors below may cause this cancer, but they may be contributing factors.

  • In most cases, there is no identifiable cause of the soft tissue sarcoma.
  • Sarcomas can sometimes occur because of genetic abnormalities in tumour suppressor genes, such as the p-52 (p-glycoprotein) gene or retinoblastoma gene. Tumour suppressor genes keep cells from dividing too quickly. Abnormalities in these genes could cause cells to grow out of control and may lead to cancer.
  • Previous chemotherapy can increase a patient's risk of developing soft tissue sarcoma.
  • Patients who have received past treatment with radiation therapy have a higher risk of developing sarcoma in that area.
  • It is suspected that large amounts of occupational exposure to herbicides such as phenoxyacetic acids, wood preservatives such as chlorophenols, or plastic manufacturing chemicals such as vinyl chloride may increase the risk of developing soft tissue sarcomas.
  • Exposure to vinyl chloride, a chemical used in plastic manufacturing, can increase the risk of developing soft tissue sarcoma.
  • Statistics - most recent available statistics:
    • BC - Number of Cancer Cases: there were 151 new cases of soft tissue cancers diagnosed in 2012.
    • Canada - There were 1165 new cases of soft tissue cancers diagnosed in Canada in 2010.

Can I help to prevent it?

Limit occupational exposure to chemicals (such as phenoxyacetic acids, chlorophenols and vinyl chloride). 

Screening for this cancer

No effective screening program exists for the cancer yet.

Signs and Symptoms

  • Symptoms are dependent on the location of the tumour.
  • The first symptom that is usually noticed is a painless lump growing in the muscle or under the skin.
  • If the tumour is pressing against nearby organs, nerves or muscles there may be more symptoms such as:
    • Weight loss
    • Fever
Diagnosis & staging


These are tests that may used to diagnose this type of cancer.

  • Physical examination.
  • A chest x-ray is used to determine if the cancer has spread to the lungs.
  • A computerized tomography scan (CT Scan) produces a three dimensional image of the tumour and screens for spread to the lungs if the chest X-ray was normal.
  • A magnetic resonance imaging scan (MRI) produces detailed images of the tumour.
  • A biopsy requires the removal of a small amount of tissue for examination under a microscope to determine if the tumour is cancerous. Biopsy should be approached with caution, and  a surgical oncologist must be consulted.
  • A routine bone scan is done for patients with rhabdomyosarcoma or soft tissue variants of Ewing's/ peripheral neuroectodermal tumour (PNET). 

For more information on tests used to diagnose cancer, see our Recommended Websites, Diagnostic Tests section.

Types and Stages

Types of Soft Tissue Sarcomas

The tumours are divided into groups named for the tissue type that the sarcoma cells most closely mimic.


  • Fibrosarcomas often occur around scars, muscles, nerves, tendons and around the lining of the bone.
  • The cancer can spread through the bloodstream to the lungs.
  • It is most frequent in older adults.


  • These tumours develop in the fat tissue of the thigh, groin, buttocks area, or abdomen.
  • These tumours may be large but their large size does not necessarily mean that they are fast-growing.
  • They are different from and do not arise from lipomas (non-cancerous fatty tumours).
  • Liposarcomas are most common in older adults.
  • A very aggressive round cell variant may be treated with adjuvant chemotherapy along with surgery and radiation.


  • Rhabdomyosarcoma is the most common soft tissue sarcoma of childhood. It generally affects children between the ages of two and six.
  • Rhabdomyosarcomas can spread quickly through the bloodstream to distant parts of the body.
  • Rhabdomyosarcomas are divided into subtypes:
    • Embryonal – occurs in the head, neck and eye
    • Embryonal botryoid – occurs in the genito-urinary tract
    • Alveolar – occurs in the muscles of arms and legs
    • Adult pleomorphic or anaplastic - occurs in older kids and adult patients, usually in the muscles of arms and legs.
  • Treatment includes surgery, radiation and chemotherapy.


  • Leiomyosarcomas are tumours of the smooth muscle that commonly arise in the uterus or in blood vessels.

Angiosarcomas and Lymphangiosarcomas

  • Angiosarcomas arise in vascular tissue and Lymphangiosarcomas arise in the lymphatic system.
  • These cancer cells easily spread into the bloodstream.
  • Lymphangiosarcoma may be seen in patients with chronic lymphedema.

Synovial Cell Sarcomas

  • Synovial Cell Sarcoma usually occurs in tissue next to the joints, especially in the knee, ankle and hand.
  • These tumours, as with other soft tissue sarcomas, can occur anywhere in the body, even in the heart.
  • Occasionally they may spread to the skin, notably the scalp.
  • Spread to the lymph nodes is uncommon.

Malignant Peripheral Nerve Sheath tumour (MPNST) (previously called Neurofibrosarcoma)

  • MPNST develops in the cells that surround a nerve.
  • It may arise in patients with neurofibromatosis (a genetic disorder of the nervous system that effects the development of nerve cell tissues).
  • As the tumour grows it may cause pain or dysfunction.

Malignant Fibrous Histiocytoma (MFH)

  • Malignant Fibrous Histiocytoma is a term that describes a high grade soft tissue tumour that does not look like any specific subtype of sarcoma.
  • It can be found anywhere in the body.
  • In superficial sites such as the skin, it may behave like a non-cancerous tumour despite fast growing cells, but must be adequately removed with a cancer-type surgery.
  • When MFH occurs deep within body cavities or muscles it may be very fast growing.

Gastrointestinal Stromal Tumour (GIST)

  • GIST is one of the most common types of sarcoma with approximately 50 cases per year in BC.
  • Patients may have symptoms such as a lump in their abdomen or very low red blood cells counts (anemia). 
  • Sometimes GISTs may be discovered when a patient is having a scan or operation for a different reason.
  • Gastrointestinal Stromal Tumours were previously called leiomyosarcoma of the gastrointestinal tract, but they are now believed to be related to the cells which control normal bowel contractions.
  • GIST may arise anywhere within the abdomen, but most commonly from the stomach and small bowel.
  • The cells behave like normal cells and grow at a slow rate. However, it may be very hard to prevent recurrence even if the tumour has been surgically removed.
  • Spreads to liver first rather than to the lungs.
  • Drug treatment may be used for patients with high risk tumours and for patients who have had spread of the cancer to other sites.

Kaposi Sarcoma   

  • Kaposi Sarcoma (KS) is an uncommon cancer that occurs in a classic slow-growing form and also in an AIDS-related form. 
  • Classic KS usually occurs in older people, usually over 70 years old, of Russian-Jewish, Italian and African origin.
  • KS that is AIDS-related occurs in people who are infected with the human immunodeficiency virus (HIV) or who have developed acquired immunodeficiency syndrome (AIDS). The skin lesions of people with KS contain human herpesvirus-8 (HHV-8), also known as Kaposi sarcoma herpesvirus (KSHV). Not everyone infected with HHV-8 gets KS. 
  • People with HHV-8 who are most at risk include those with weakened immune systems as a result of disease, drugs, or an organ transplant. 
  • Men are affected over twice as often as women. 
    NOTE:  Available statistics do not have information about the inclusion of transgender and gender diverse participants. It is unknown how these statistics apply to transgender and gender diverse people.  Patients are advised to speak with their primary care provider or specialists about their individual considerations and recommendations


Staging describes the extent of a cancer. The TNM classification system is used as the standard around the world. In general a lower number in each category means a better prognosis. The stage of the cancer is used to plan the treatment.

  • G (Grade) describes how the tumour cells look under the microscope
  • T describes the site and size of the main tumour (primary)
  • N describes involvement of lymph nodes
  • M relates to whether the cancer has spread (presence or absence of distant metastases)


Cancer therapies can be highly individualized – your treatment may differ from what is described below.

  • The complete surgical removal of the tumour is the most important treatment.
  • For tumours of arms, legs or superficial trunk, radiation therapy may be used before or after surgery to decrease the chance of tumour recurrence, particularly for quick-growing tumours.
  • Surgery to the lung may be offered to patients where the cancer has spread to the lung.

Follow-up after Treatment

  • Guidelines for follow-up after treatment are covered on our website. Follow the link, click on Chapter 6. Management, then see the link to Follow Up after part 06.
  • You will be returned to the care of your family physician or specialist for regular follow-up. If you do not have a family physician, please discuss this with your BC Cancer oncologist or nurse.
  • Follow-up testing is based on your type of cancer and your individual circumstances.
  • Life after Cancer focuses on the issues that cancer survivors can face.
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