Myxofibrosarcoma

Myxofibrosarcoma (pronounced “mik-so-fi-bro-sar-ko-muh”) is a rare soft tissue sarcoma (cancer) that usually starts in your leg. It looks like a small lump. Like other sarcomas, it starts in connective tissues. Connective tissue includes bones, cartilage and fat. Myxofibrosarcoma (MFS) typically grows in connective tissues beneath your skin. Less often, it grows in deeper tissues surrounding your muscles.

MFS is an aggressive cancer. It can spread to other parts of your body and often comes back (recurs) after surgery to remove it. Still, your experience of myxofibrosarcoma depends on lots of factors that your healthcare provider will discuss with you.

Symptoms of myxofibrosarcoma

You may not have any symptoms at first. Eventually, you may notice:

• A slow-growing (often painless) lump beneath your skin (usually your legs or arms)
• Swelling where the lump is

Myxofibrosarcoma causes

Medical experts don’t know what causes myxofibrosarcoma. Like all types of cancer, it develops when a change (mutation) happens in your cells’ DNA. The mutation tells your cells to multiply when they shouldn’t. Eventually, the cells form a tumor. Over time, the cells can break off from the tumor and travel to other parts of your body. This is called metastatic cancer.

More research is needed to understand what causes the mutation in the first place.

Risk factors

MFS is most common in adults ages 60 to 80. You’re slightly more likely to receive a diagnosis if you’re male.

Doctors haven’t found risk factors specific to myxofibrosarcoma. But the things that increase your chance of getting a sarcoma may also increase your risk of MFS. Factors include:

• Genetic conditions that increase your sarcoma risk in general (examples include Li Fraumeni syndrome and neurofibromatosis Type 1)
• Exposure to certain chemicals, like arsenic and herbicides
• A history of radiation therapy

How doctors diagnose this condition

To diagnose MFS, a healthcare provider will do a physical exam and ask about your symptoms. They may ask if the lump has grown since you first noticed it.

Still, it may resemble lots of other growths. You’ll likely need more tests for an accurate diagnosis, like:

• Imaging scans: A CT scan or an MRI allows your provider to see the tumor inside your body.
• Needle or open biopsy: Your provider will remove a small sample of the growth and test it in a lab. They can tell if it’s MFS based on the type of cells.

Myxofibrosarcoma staging

Cancer staging helps providers know how advanced MFS is. It helps them plan treatments. To stage MFS, they consider factors like a tumor’s size and how much it’s grown into your tissues. They’ll also see if it’s spread. MFS usually spreads to your lungs first.

The tumor “grade” is also important. High-grade tumors have more abnormal cells than low-grade ones. They’re more likely to grow and spread fast. Providers grade MFS as low, intermediate or high.

How is myxofibrosarcoma treated?

Myxofibrosarcoma can be challenging to treat because it doesn’t form a well-defined tumor. Instead, it often grows into nearby healthy tissue, which can make it harder to remove completely with surgery.

To account for this, providers remove MFS and a small amount (“margin”) of surrounding healthy tissue. They check to ensure no cancer cells are hiding out in healthy tissue. Other treatments you may need include:

• Radiation therapy: Radiation before surgery can shrink the tumor so it’s easier to remove. You may need it after surgery to kill any remaining cancer cells. This lowers the chance of MFS coming back.
• Chemotherapy: Chemo isn’t a common treatment for MFS. But your provider may recommend chemotherapy in addition to radiation therapy. You may need it if the cancer comes back after surgery.

Medical experts are developing new treatments for MFS, like immunotherapy and targeted therapy. Your provider may suggest you take part in a clinical trial to access these treatments.

Will I need amputation to treat myxofibrosarcoma?

Not necessarily. Removing an arm or leg (amputation) used to be a common treatment for myxofibrosarcoma. This was to ensure no cancer cells remained after surgery. Today, healthcare providers usually do limb salvage surgery to avoid amputation. The goal is to get rid of the cancer without limiting your mobility.

When should I see my healthcare provider?

You’ll see your provider during follow-up appointments to make sure you’re healing OK. Visits may involve routine blood tests and imaging to see if the cancer has come back.

As part of your recovery, you may need to meet with a physical therapist. They can help you adjust to any changes in your limbs after surgery.

What can I expect if I have this condition?

For most people, an MFS diagnosis means surgery and (often) radiation therapy. It also means that your healthcare provider will monitor you closely to see if the cancer has returned. Research shows that between 16% and 61% of people have MFS return within five years of treatment. Tumors that recur often come back at a higher grade.

The range is broad, though. This is partly because MFS is so rare that more research is needed to know how often it comes back. Also, lots of factors can affect your outlook (prognosis). This includes the tumor’s:

• Size (tumors less than 5 centimeters — a little under 2 inches — have a better outlook)
• Depth (tumors that grow into deep tissue are more likely to spread)
• Stage
• Grade

What is the survival rate for myxofibrosarcoma?

The five-year overall survival rate for myxofibrosarcoma is 67%. This means that 6 to 7 out of 10 people diagnosed with MFS are alive five years later.

It’s important to remember that survival rates don’t tell the whole story about a diagnosis. After all, these numbers don’t take into account the specifics, like how big a tumor is and whether the cancer has spread. These are things your provider can discuss with you.

Is there anything I can do to feel better?

Cancer (both the disease and the treatment) can take a major toll on your well-being. Although you’re living with a serious disease, it’s still important to attend to the basics each day. Eating nutritious foods and getting enough rest matter more than ever. These little things are actually huge when it comes to feeling better.

Take advantage of every resource available to you. This includes cancer survivorship programs. Work with your healthcare provider to develop a plan that makes sense for you.