Myxofibrosarcoma (MFS) is a type of soft tissue sarcoma (cancer). It starts as a small lump. As the lump grows, you may have pain or swelling. Usually, healthcare providers use surgery to remove the growth. MFS is more likely to return after treatment than other types of soft tissue sarcomas. Follow-up imaging increases your chances of treating MFS early.


What is myxofibrosarcoma?

Myxofibrosarcoma (MFS) is a type of soft tissue sarcoma cancer that starts in connective tissues. Connective tissues include bones, cartilage and fat that provide structure and protection around your organs. MFS often grows in your arm or leg and may look like a small lump.

Myxofibrosarcoma may grow in connective tissues directly underneath your skin. Or it may grow in deeper connective tissues surrounding your muscles.

MFS is an aggressive tumor, meaning it spreads (metastasizes) quickly to other parts of your body. It’s more likely to grow back (recur) after treatment than some other types of cancers.


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What is high-grade myxofibrosarcoma?

Healthcare providers use a grading scale to classify tumors. Low-grade tumors contain fewer cells that divide quickly, so these tumors grow and spread slowly. High-grade tumors have more dividing cells and grow quickly.

Who might get myxofibrosarcoma?

Myxofibrosarcoma is more common in adults over 50 and slightly more common in people designated male at birth (DMAB) than people designated female at birth (DFAB).

Other factors that can increase your risk of malignant soft tissue tumors, including MFS, include:

  • Genetics: Some genetic conditions may increase your risk of soft tissue sarcomas.
  • Environmental factors: Certain chemicals, such as arsenic and herbicides, can raise your risk.
  • Radiation therapy: A history of radiation therapy may increase your risk of certain cancers, such as myxofibrosarcoma.


How common is myxofibrosarcoma?

Myxofibrosarcoma is rare. It’s one of the most common types of soft tissue sarcomas. However, soft tissue sarcomas make up only about 2% of all cancer diagnoses.

Symptoms and Causes

What causes myxofibrosarcoma?

Experts don’t know the cause of myxofibrosarcoma. Like all types of cancer, it develops when a change happens in your cells’ DNA. This change tells your cells to multiply. As your cells multiply, they form an irregular mass called a tumor.


What are the symptoms of myxofibrosarcoma?

You may not have any symptoms of myxofibrosarcoma when it first appears. As the tumor grows, you may notice a lump beneath your skin. The lump is often painless, but you may have discomfort or swelling.

Diagnosis and Tests

How is myxofibrosarcoma diagnosed?

Myxofibrosarcoma may be challenging to diagnose because it can appear similar to other types of growths. Your healthcare provider may ask you if the mass has grown since you first noticed it.

To find out if you have MFS or another type of growth, your healthcare provider may perform:

  • Imaging scans, such as a CT scan or MRI, look at whether the growth extends to your deep muscle tissues.
  • Needle or open biopsy takes a small sample of the growth to examine in a lab.
  • Chest X-ray checks if cancer has spread to your lungs. If MFS spreads (metastasizes), it’s most likely to go to your lungs.

Management and Treatment

How is myxofibrosarcoma treated?

Your healthcare provider surgically removes the tumor and a small amount of surrounding tissue. You may have radiation therapy before or after surgery to shrink the tumor or lower the risk of it coming back. Healthcare providers are less likely to use chemotherapy for myxofibrosarcoma than for other types of cancer.

Myxofibrosarcoma treatment depends on several factors, including:

  • Grade: Surgery is usually the only treatment needed for a low-grade myxofibrosarcoma. If you have a high-grade myxofibrosarcoma, you may have surgery along with other treatments such as radiation therapy.
  • Stage: Healthcare providers use staging to determine how much cancer has spread. The higher the stage, the more cancer has spread throughout your body. In general, higher-stage myxofibrosarcoma is more likely to require surgery along with other treatments.
  • Size: If the tumor is smaller than 2 inches (about 5 centimeters), it’s more likely that surgery will be your only treatment. You may need additional treatment, such as radiation therapy, for a larger tumor.
  • Depth: A tumor that extends to your deeper tissues, such as between your muscles, may require surgery and radiation therapy.

Will I need amputation to treat myxofibrosarcoma?

No. Removing your arm or leg (amputation) used to be a common treatment for myxofibrosarcoma. Today, healthcare providers do everything they can to avoid amputation.


How can I reduce my risk of myxofibrosarcoma?

There’s no guaranteed way to prevent myxofibrosarcoma. With all types of cancer, healthy lifestyle habits may lower your risk. You may wish to avoid risk factors, such as radiation or chemical exposure, as much as possible.

Outlook / Prognosis

What is the prognosis for myxofibrosarcoma?

Myxofibrosarcoma is more likely to come back after treatment than other types of soft tissue sarcomas. Up to 1 in 2 people have myxofibrosarcoma return within five years of treatment.

Low-grade myxofibrosarcoma is less likely to return than higher-grade tumors. After myxofibrosarcoma treatment, you’ll have regular follow-up imaging with your healthcare provider. If the tumor does return, regularly seeing your healthcare provider increases the chances of finding and treating myxofibrosarcoma early.

What is the survival rate for myxofibrosarcoma?

Myxofibrosarcoma has better survival rates than some other types of soft tissue sarcomas. In one study, most people with myxofibrosarcoma lived five years or longer after treatment.

Living With

What else should I ask my provider?

If you have symptoms or received a diagnosis of myxofibrosarcoma, you may want to ask your healthcare provider:

  • What are the early signs of myxofibrosarcoma?
  • What tests do I need to diagnose myxofibrosarcoma?
  • What are my treatment options?
  • Do I have low-grade or high-grade myxofibrosarcoma?
  • Is there anything I can do to lower the risk of myxofibrosarcoma returning?

A note from Cleveland Clinic

Myxofibrosarcoma is a type of soft tissue sarcoma. It often starts as a small, painless lump. As the lump grows, it may cause discomfort or swelling. Usually, healthcare providers remove the growth with surgery. Myxofibrosarcoma is more likely to come back after treatment than other types of soft tissue sarcomas. Seeing your healthcare provider regularly can increase your chances of finding and treating MFS early if it does return.

Medically Reviewed

Last reviewed on 03/17/2022.

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