Summary
- A plantar fibroma is the most common reason for a lump to develop on the arch of the foot. These are often small but can grow steadily to reach sizes of 5cm or more.
- They may occur as a single lesion or may present as multiple lesions typically along the medial border of the plantar fascia.
- They are usually benign and are composed of dense, fibrous tissue.
- Many patients with plantar fibromas do not have any symptoms and when they do it is often only a vague discomfort from “walking on a lump”.
Diagnostic tips
- Plantar fibromas are usually located on the inside of the arch of the foot (usually feel smooth and rubbery).
- Lumps are not usually tender to touch although they may become irritated with prolonged walking.
- May or may not have pain (pain usually caused by shoes pushing against the lump in the arch).
Tests and Imaging
- X-rays are often negative, although if the x-rays are taken in such a way as to highlight the soft-tissues an outline of a mass may be seen.
- Ultrasound and MRI will show a smooth, consistent (homogenous) mass that is affiliated with the plantar fascia. This allows differentiation of other causes of masses in the foot such as lipomas, ganglions, neuromas, herniation of the plantar fascia, and tumors.
Immediate Treatment
- Short term NSAID’s.
Possible Referral
- Podiatry for footwear advice/modification and fabrication of a soft-accommodating or well moulded custom-made shoe insert
- Surgery for operative treatment which involves excising of the mass (typically avoided due to the high recurrence rate).
