Soft Tissue Sarcoma

Soft tissue sarcomas are rare cancerous tumors that develop in the tissues that support and surround your bones and organs. (Think muscles, tendons and fat cells.) Soft tissue sarcomas usually develop in your arms, legs, chest and the back of your belly, or retroperitoneum.


person with soft tissue sarcoma cancer
Soft tissue sarcoma in lower leg muscle.

What is soft tissue sarcoma?

Soft tissue sarcomas are rare cancerous tumors in the tissues that support and surround your bones and organs. (Think muscles, tendons, fat and skin). You may develop soft tissue sarcomas anywhere but they usually appear in your arms, legs, chest and in the space behind your belly (retroperitoneum).


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Are soft tissue sarcomas common?

No, they aren’t. The American Cancer Society estimates about 13,400 adults and children will learn that they have soft tissue sarcoma in 2023. Soft tissues sarcomas represent 1% of all cancers in adults. They represent 7% of all cancers in children up to age 15 and 3% of all cancers in children age 14 and younger.

Types of soft tissue sarcomas

There are 70 different types of soft tissue sarcoma. Some soft tissue sarcomas are more common in adults than in children and adolescents (older children between ages 15 and 19).

According to the American Cancer Society, the most common soft tissue sarcomas in adults are:

  • Undifferentiated pleomorphic sarcoma. This cancer develops in soft tissue in your legs, arms or chest, quickly spreading to other areas of your body.
  • Liposarcoma. You may have this soft tissue sarcoma type in your belly but it may also appear in your thighs and other areas of your body.
  • Leiomyosarcoma. This soft tissue sarcoma starts in your smooth muscles. You have smooth muscles in your belly, bladder, uterus, intestines and your blood vessels.

The most common soft tissue sarcomas in teenagers and young adults are:

  • Rhabdomyosarcoma. This is a very rare soft tissue sarcoma. Healthcare providers can treat this condition, but rhabdomyosarcoma may come back (recur). About 70% of people with rhabdomyosarcoma are alive five years after diagnosis.
  • Ewing sarcoma in soft tissue. This sarcoma type usually develops in tissues next to your bones. Each year, healthcare providers diagnose about 200 cases of Ewing sarcoma in soft tissue. This condition mostly affects people ages 10 to 20. Based on age, the overall 5-year survival rate for this type of cancer is 76% for children younger than 15 and 59% for teenagers between ages 15 and 19.

How serious is soft tissue sarcoma?

Soft tissue sarcoma can be a serious medical issue. Like many forms of cancer, healthcare providers have more success treating soft tissue sarcomas if they diagnose the tumor before it spreads. Without treatment, soft tissue sarcomas may spread (metastasize) and affect other areas of your body.

Symptoms and Causes

What are soft tissue sarcoma symptoms?

Many soft tissue sarcoma symptoms are similar to other, less serious conditions. You should contact a healthcare provider if you have:

  • A new lump or a fast-growing lump anywhere on your body.
  • A lump that starts to hurt.
  • Belly pain that’s getting worse.
  • Blood in your poop or poop that appears black.
  • Nausea and vomiting.
  • Losing weight without trying.

What do soft tissue sarcomas look like?

A soft tissue sarcoma in your leg or arm may look like a lump under your skin. It may look like the kind of lump or bump you’d get from smacking your leg or arm against a hard object like a table leg.

The difference between that kind of lump or bump is that soft tissue sarcomas may not hurt or bruise like a bump from an injury. Soft tissue sarcomas also don’t go away like bumps from injuries. Instead, they may get larger. Sometimes they start to hurt.

You may also have soft tissue sarcomas in your organs, like the back of your belly or the smooth muscles in your intestines. You won’t see those kinds of soft tissue sarcomas.


What causes soft tissue sarcoma?

Researchers are still unraveling what causes soft tissue sarcomas. They’ve found some potential risk factors such as certain inherited disorders and activities. A risk factor is anything that increases the risk you’ll get sick. (Having a risk factor doesn’t mean you’ll get sick. It means you could get sick.)

Inherited (genetic) disorders

Inherited disorders happen when people inherit genetic mutations (changes in their genes) that affect how their bodies work. Your provider may recommend genetic testing if your family members have certain inherited disorders. Inherited disorders that increase soft tissue sarcoma risk include:

Other soft tissue sarcoma risk factors

Other risk factors include:

  • Having radiation therapy.
  • Having lymphedema in your arms or legs that’s lasted for a long time.
  • Exposure to chemicals including thorium dioxide, arsenic or vinyl chloride.
  • Having human immunodeficiency virus (HIV)/AIDS increases your risk of Kaposi sarcoma.

Diagnosis and Tests

How is it diagnosed?

Healthcare providers will ask you about your symptoms, specifically unusual lumps or bumps on your body. They’ll do a physical examination. They may do several tests, including:

  • X-ray. X-rays take pictures of your soft tissues.
  • Computed tomography (CT). CT uses computers to combine many X-ray images into cross-sectional views of the inside of your body. Providers often use this test to look for soft tissue sarcomas in your chest and the back of your belly.
  • Magnetic resonance imaging (MRI). MRI uses a large magnet, radio waves and a computer to create clear images of your internal organs. Your provider may order this test if X-rays show abnormal growths and your provider wants clearer pictures.
  • PET scan. This test uses a special glucose tracer that’s concentrated in cancer cells. The tracer detects higher-than-normal glucose in your body. High glucose levels may be a sign of a fast-growing cancerous tumor.
  • Ultrasound. This test relies on sound waves and their echoes to develop pictures of parts of the body.
  • Biopsy. Your provider obtains tissue that a medical pathologist will examine under a microscope. The pathologist may do several tests to identify the sarcoma type, stage and grade. Knowing tumor grade is how providers determine if a tumor is likely to grow slowly, grow fast or spread (metastasize).

Do healthcare providers stage soft tissue sarcomas?

Yes, they do. Providers use cancer staging systems to develop treatment plans and prognoses (what you can expect if you have a soft tissue sarcoma). Providers consider the following factors in staging soft tissue sarcomas:

  • Tumor size.
  • Original location.
  • If the tumor has spread to other areas of your body.
  • Tumor grade. The grade includes how much cancer cells look like normal cells (differentiation), how fast cancer cells are dividing (mitotic count) and how much of the tumor has cells that are dying (tumor necrosis).
What are the stages of soft tissue sarcomas?

Soft tissue sarcomas have four stages (Stage I to Stage IV) that combine information about tumor size, location and activity, and tumor grade. There are four grades for soft tissue sarcoma (GX to G3). In general, the lower the tumor’s grade, the better the prognosis. Stage groups are:

  • Stage I: The tumor is small and low-grade (GX or G1).
  • Stage II: The tumor is small and of higher grade (G2 or G3).
  • Stage III: The tumor is larger and of higher grade (G2 or G3).
  • Stage IV: The cancer has spread to other parts of your body. The original tumor can be any size, any grade, and may or may not have spread to the regional lymph nodes (any G).


Management and Treatment

What are treatments for soft tissue sarcomas?

Treatments vary depending on factors such as tumor type, where it’s located and the tumor stage. In general, providers use surgery to treat small soft tissue sarcomas that haven’t spread. They may combine surgery with medical treatments, including:


Can this be prevented?

There’s no known way to prevent soft tissue sarcoma. If you know you have soft tissue sarcoma risk factors, ask a healthcare provider what symptoms may be signs you have the condition. That way, you and your provider can take steps to treat the condition before tumors spread.

Outlook / Prognosis

Is soft tissue sarcoma curable?

That depends. The most common treatment is surgery to remove tumors. If a surgeon can remove a tumor before it grows and spreads, they may say they’ve cured the condition. But soft tissue sarcomas can come back (recur) after surgery and other treatment.

What are the survival rates for this condition?

Survival rates are estimates based on the experiences of large groups of people. What’s true for the people in those groups may not be true for you. If you have questions about your survival rate, ask your healthcare provider to explain what you may expect.

Overall, experts estimate about 65% of adults with soft tissue sarcoma are alive five years after diagnosis.

Survival rates for soft tissue sarcoma in children and adolescents vary depending on the soft tissue sarcoma type. About 70% of people with rhabdomyosarcoma are alive five years after diagnosis. Ewing sarcoma of soft tissue survival rates vary.

Overall, 76% of children younger than age 15 are alive five years after diagnosis. An estimated 59% of adolescents (ages 15 to 19) are alive five years after diagnosis.

Living With

How do I take care of myself?

If you have — or your child has — soft tissue sarcoma, the following suggestions may be helpful:

  • Chemotherapy treatments affect people’s appetites. If you or your child has trouble eating, talk to a nutritionist. They’ll have recommendations for ways you or your child can get the nutrition needed to stay strong during treatment and recovery.
  • Cancer treatment can be exhausting. Try to rest when you need to, not just when you have time.
  • Cancer is stressful. You might find activities such as meditation, relaxation exercises or deep breathing help to ease your stress.
  • Cancer can be lonely, particularly for kids who are going through something their friends may not understand. Your child may benefit by working with a child life specialist. Child life specialists are providers who help children cope with medical experiences.
  • Soft tissue sarcomas can come back after treatment. That’s a common concern for cancer survivors. If you or your child is worried cancer will come back, ask your providers about cancer survivorship support.

When should I see my healthcare provider?

In general, you’ll have follow-up appointments after treatment so your provider can monitor your overall health and your specific condition.

When should I go to the emergency room?

Ask your healthcare provider what symptoms may indicate you need immediate medical attention, including what to do if you’re having trouble managing treatment side effects.

A note from Cleveland Clinic

Having a rare cancer like soft tissue sarcoma may make you feel as if you’re traveling an unfamiliar road without a map to guide you home. You know you need information so you can take steps to get well, but you may be frustrated if you can’t find accurate information about rare cancers. You may have questions for which there aren’t immediate and clear answers.

It may help to know you’re not alone on the unfamiliar road that is rare cancer. Your healthcare team understands what you’re going through. They’ll do everything they can to help you find answers, like explaining your diagnosis in terms you understand, outlining treatment options so you feel confident about treatment decisions or helping you map out your life after you finish treatment.

Medically Reviewed

Last reviewed on 01/27/2023.

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