Plantar Fibroma

A Patient's Guide

Plantar fibromas are benign (non-cancerous) growths that develop in the plantar fascia, a thick band of connective tissue that runs along the sole of the foot from the heel to the toes. These nodules are typically firm and embedded within the fascia, and although they are not malignant, they can cause discomfort or pain, especially when walking or standing.

Plantar fibromas are part of a condition known as plantar fibromatosis or Ledderhose disease, which shares some similarities with other fibrous tissue conditions like Dupuytren’s contracture in the hand or Peyronie’s disease in the penis. Though plantar fibromas are less common, they can significantly affect foot function and quality of life when symptomatic.

The exact cause of plantar fibromas is not fully understood, but factors such as genetic predisposition and trauma to the foot are believed to be the most likely factors that play a role in their development.

Symptoms and Signs

The hallmark of a plantar fibroma is the presence of a palpable lump in the arch of the foot, usually located in the medial (inner) aspect of the sole. This nodule is typically:

Firm and rubbery to the touch
Embedded within the plantar fascia
Slowly growing over time
Usually painless initially but may become painful with pressure

Many individuals first notice the fibroma incidentally, such as when walking barefoot or during a foot massage. Over time, especially if the fibroma enlarges or if there are multiple nodules, it may begin to cause localized discomfort or pain, particularly when walking, wearing shoes that apply pressure on the arch, or standing for prolonged periods.

Other signs and symptoms may include:

Pain on weight-bearing, especially when the lump is pressed against the inside of a shoe
Shoe-fitting difficulties due to the raised lump
Reduced flexibility or stiffness in the foot due to involvement of the plantar fascia
Occasionally, multiple fibromas may develop, especially in those with bilateral (both foot) involvement or in association with fibromatosis in other parts of the body

While plantar fibromas are generally benign and slow-growing, they can become functionally limiting depending on their size, location, and number.

Investigations

A clinical diagnosis is often sufficient in typical cases of plantar fibromas, especially when the patient presents with characteristic findings. A physical examination will typically show:

A non-mobile, firm nodule located in the central or medial plantar fascia.
No signs of skin changes, inflammation, or systemic illness are typically present.

However, further investigations are sometimes required to confirm the diagnosis, rule out other causes of foot lumps, or plan for treatment.

Ultrasound:
- Often the first-line imaging test due to its availability and non-invasive nature.
- Shows a hypoechoic (dark) mass within the plantar fascia.
MRI (Magnetic Resonance Imaging):
- Considered the gold standard for detailed evaluation.
- Helpful in assessing the size, extent, and depth of the fibroma, and in distinguishing it from other soft tissue masses such as lipomas, ganglion cysts, or sarcomas.
- A plantar fibroma typically appears as a well-defined, low-signal intensity lesion on both T1 and T2-weighted images due to dense fibrous tissue.
Biopsy - Tissue Sampling
- A core needle biopsy or excisional biopsy can be performed to obtain a definitive histological diagnosis. but it is rarely necessary unless the lesion has atypical features or there is concern for malignancy (cancer).

Conservative Treatment

Treatment aims are to relieve pain, promote healing, and restore normal function. A combination of conservative and, in some cases, surgical interventions is employed based on the severity of the condition. Conservative treatments include:

Orthotics and Shoe Modifications: Custom insoles with arch support and padding can offload pressure from the nodule. Avoid shoes with hard soles or minimal cushioning.
Stretching Exercises and Physiotherapy: Aimed at maintaining flexibility of the plantar fascia and reducing strain.
Topical and Oral Medications: Nonsteroidal anti-inflammatory drugs (NSAIDs) can provide pain relief but can interfere with the function of the kidneys, lungs and stomach lining. Topical agents like verapamil cream have been tried anecdotally, though evidence is limited. In the UK, verapamil gel (15% strength) is a compounded drug meaning it has to be individually made which can be expensive and is not typically covered under patients' insurance policies.
Steroid Injections: Corticosteroid injections may reduce inflammation and temporarily shrink the fibroma. However, repeated steroid injections can weaken the plantar fascia and risk rupture.
Enzyme Injections: Hyalurionidase (Hyalase) is now used in my practice as a first line treatment in symptomatic patients with small fibromas. Repeated injections can be used to although if there is no improvement with three injections, then further injections are not advised.
Radiotherapy: Low-dose radiation has shown some efficacy in halting progression and reducing pain, although there are concerns about long-term risks.

Surgical Treatment

Surgery is considered a last resort and has largely fallen out of favour due to the risk of recurrence and side effects. It should only be considered when there is significant impact on mobility or quality of life and:

The fibroma is large or growing.
Pain is persistent despite conservative therapy.

Surgical options include:

Local excision: Removal of the fibroma alone. This has a high recurrence rate (over 50%) because some affected fascia may remain.
Wide excision or fasciectomy: Removal of the fibroma along with a portion of the surrounding plantar fascia. This reduces recurrence risk but may result in:
- Plantar fascia weakness
- Arch collapse
- Nerve damage or scarring

Post-operative care includes immobilisation, gradual return to weight-bearing, and physiotherapy. Recurrence remains a concern even after surgery and although follow-up is recommended, there may be little further treatment that can be undertaken.

Summary

Plantar fibromas are benign nodules that arise within the plantar fascia and can range from asymptomatic to painful and functionally limiting. While the exact cause remains unclear, early recognition and treatment may prevent unnecessary discomfort and help maintain foot function.

In most cases, conservative treatment—including orthotics, stretching, and medications—can provide relief. Injections are often effective with persistent symptoms that interfere with daily life. Surgery carries risks of recurrence and potential complications, so treatment should be individualised and carefully discussed with the patient.

If you would like to discuss whether the lump in the sole of your foot could be a plantar fibroma, please get schedule an appointment with Shelain Patel who has extensive experience of dealing with this condition.