Myxofibrosarcoma (MFS) is a type of cancer that begins in the connective tissue. It tends to happen in the arms and legs.

MFS starts as a growth of cells that can grow into healthy body tissue. MFS might cause a lump under the skin that grows slowly. It often isn't painful. MFS happens most often in adults over 50.

MFS is one of many types of cancer that start in the connective tissues that support and surround the organs, bones and muscles. Doctors sometimes call these cancers soft tissue sarcomas.

Doctors are still learning about what makes MFS different from other types of soft tissue sarcoma. Sometimes it looks like a growth that isn't cancer. This can make it hard to get a correct diagnosis and prompt treatment to control the cancer.


Tests and procedures used to diagnose MFS include:

  • Physical exam. Your health care provider will ask about your symptoms and health. The provider will check your body for signs of cancer.
  • Imaging tests. Imaging tests can help your provider see the cancer's size. One test used for this reason is MRI. You might have other imaging tests to look for signs that the cancer has spread to other parts of the body. This might be with a CT scan.
  • Getting a sample of tissue for testing. A biopsy procedure involves taking some of the suspicious tissue for testing in a lab. Lab tests can show if you have cancer and what type. To get the tissue sample, sometimes your provider uses a needle to collect the cells. Sometimes surgery is needed to get the tissue sample.

MFS diagnosis can be hard because it looks like other types of cancer and other conditions that aren't cancer. Careful imaging and advanced lab tests can help your health care team make the correct diagnosis.


MFS treatment often involves surgery to remove the cancer. Other treatments include radiation therapy and chemotherapy.

MFS often comes back after treatment. When it comes back, it can be more aggressive. Your health care team creates a treatment plan with the goal of getting rid of all the cancer cells. This makes it more likely that the cancer won't come back.

Which treatment is best for you will depend on your cancer. Your care team considers the size and location of your cancer. A cancer that grows quickly has different treatment options than a cancer that grows slowly.


The goal of surgery is to cut out as much of the cancer as possible. If all the MFS is removed, surgery might be the only treatment needed.

Sometimes it's hard to get all the MFS because this cancer tends to spread out as it grows. It can grow deep into the tissue. Sometimes surgeons can't see all the cancer to make sure it's removed.

In the past, surgeons often had to remove a limb to get rid of all the cancer. Today that's often not needed because of newer treatments. Sometimes radiation therapy and chemotherapy are used before surgery to shrink the cancer. This makes it easier to remove.

Radiation therapy

Radiation therapy uses powerful energy beams to kill cancer cells. The energy beams can come from X-rays, protons and other sources.

Radiation might be done before surgery to help shrink the MFS. It can also be done after surgery to kill any cancer cells that might be left behind.


Chemotherapy is a drug treatment that uses chemicals to kill cancer cells. It might help control a MFS that's growing quickly. It might be an option if MFS doesn't respond to other treatments.

Content From Mayo Clinic Updated: 11/21/2023
© 1998-2024 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved. Terms of Use