Plantar Fibroma

What is a plantar fibroma?

A plantar fibroma is a rare, noncancerous (benign) growth on your plantar fascia, the rubber band-like ligament that stretches from your heel to your toes. Plantar fibromas are small — usually less than an inch — and grow on the arch of your foot. You might not even notice one at first, but eventually, a plantar fibroma can cause foot pain, especially when you’re wearing shoes.

Fibromas in your foot are always benign, which means they’re never a symptom (or cause) of cancer.

If you develop rapidly growing, invasive plantar fibromas, your healthcare provider might diagnose you with plantar fibromatosis. Either way, make sure to see your provider if you have new or painful growths on your foot. They can suggest treatment options to get you feeling better again.

Symptoms of plantar fibroma

The most common symptom of a plantar fibroma is pain on the bottom of your foot, usually in the arch. You’ll likely notice this pain for the first time when wearing shoes that put pressure on the plantar fibroma under your skin.

Depending on how big it is, a plantar fibroma can cause pressure on your foot. It might feel like there’s a stone in your shoe, but when you try to shake it out, there’s nothing there.

You might be able to see the plantar fibroma. It might look like there’s a tiny marble — less than an inch across — embedded in your skin. The skin on your foot’s arch will curve out around it, or slightly bulge in a way that’s unusual for the shape of your foot. This will be more visible and feelable if you pull your toes and ankle upward (toward your shin).

Plantar fibroma causes

There’s no clear reason people develop plantar fibromas. They appear without a known cause and can affect anyone. The only indication you might develop one is if you have certain health conditions (listed below), or a possible genetic predisposition.

Risk factors of plantar fibroma

Plantar fibromas can appear in anyone, and they have no confirmed cause, but you might be more likely to develop one if you are:

• Assigned male at birth. People assigned male at birth are twice as likely to develop plantar fibromatosis than people assigned female at birth.
• Middle-aged. People between the ages of 30 and 50 seem more likely to develop plantar fibromas than younger or older people.
• Of northern European descent. People of northern European descent are more prone to plantar fibromas than other ethnicities.
• Share a genetic predisposition. The tendency to develop plantar fibromas may be genetically inherited, meaning you might be more likely to if someone in your biological family gets them.

You may also be at increased risk of developing a plantar fibroma if you have other health conditions, including:

• Alcohol use disorder
• Diabetes
• Dupuytren’s disease
• Epilepsy
• Frozen shoulder
• Knuckle pads
• Peyronie’s disease

How doctors diagnose plantar fibromas

Your healthcare provider will ask you about your medical history and perform a physical exam to diagnose a plantar fibroma. Your provider will examine your foot, feel the growth and compare it to your other foot (if possible).

Your provider will check the mass on your plantar fascia to confirm it’s a fibroma and not something else. If they suspect other issues, you’ll need imaging tests.

If you need additional tests, your provider will explain what they’re checking for. The most common tests you’ll need include:

• Magnetic resonance imaging (MRI). An MRI will confirm the mass is a fibroma and not any other type of benign growth, like a cyst.
• Foot X-ray or bone scan. These tests will show any changes in the bones in your foot around the growth. Your provider will check for more serious conditions, like a cancerous sarcoma.
• Ultrasound. A musculoskeletal ultrasound is like an X-ray for soft tissue. Your provider can use it to take pictures of the area around the growth.

How is a plantar fibroma treated?

Plantar fibroma treatment almost always focuses on relieving your symptoms. The most common treatments include:

• Over-the-counter NSAIDs like aspirin or ibuprofen to reduce pain and inflammation
• Orthotics (inserts for your shoes)
• Offloading pads (like a donut- or horseshoe-shaped pad) placed in your shoe to take the pressure away
• Stretching
• Verapamil (a cream you put on the bottom of your foot) to reduce inflammation and shrink the fibroma
• Cortisone injections
• Physical therapy

Plantar fibroma surgery

It’s very rare to need surgery to remove (excise) a fibroma in your foot, but it’s an option if your symptoms don’t clear up or aren’t manageable with nonsurgical treatments. If you need surgery, your surgeon will explain how much of your foot’s tissues they’ll remove. There are a few techniques they can use for plantar fibroma surgery:

• Local excision. Your provider only removes the plantar fibroma itself.
• Wide excision. Your provider removes the plantar fibroma and an area between 2 and 3 millimeters — less than one-tenth of an inch — around it.
• Plantar fasciectomy. Your provider removes the entire plantar fascia ligament. This is extremely rare, in addition to how rarely people need plantar fibroma surgery in the first place.
• Percutaneous fasciectomy. Similar to a full plantar fasciectomy, your provider will use an ultrasound to guide them and remove only a portion of your plantar fascia near your heel.

When should I see my healthcare provider?

You should make an appointment with your provider if:

• You notice any new growths or changes in the shape of your foot
• You’re experiencing new pain
• You can’t walk on your foot

Never assume any mass on your foot is harmless, especially if you’ve never noticed it before. See your healthcare provider to check it out.

What questions should I ask my healthcare provider?

Questions you may want to ask your provider include:

• How should I manage my pain or other symptoms?
• Do I need orthotics or different shoes?
• Will I need surgery?
• When will the fibroma on my foot go away?

What is the outlook for a plantar fibroma?

Plantar fibromas can be annoying and uncomfortable, but they’re not life-threatening and won’t spread. Once you’ve confirmed that you have a plantar fibroma and not any other kind of growth in your foot, you should focus on treating your symptoms.

If you’re not experiencing pain or other symptoms, you should be able to do all the activities and exercises you normally do, including running and playing sports. But, if you notice new pain or pressure after running or working out, make sure to talk to your provider.