Plantar Fibroma (plantar fibromatosis) is a benign soft tissue mass generally occurring within the midarch region on the bottom of the foot. The soft tissue mass represents a thickening of the connective tissue within the plantar fascia ligament as it courses from the heel bone to the base of the toes.

The soft tissue mass is generally characterized by non-painful nodularity to the ligament in the midportion of the arch. It is usually seen on one foot but can present on both. It is similar to a process that occurs in the hand called Dupuytren’s Contracture and has been associated with other conditions including alcoholism, medicine intake, and liver disease to name a few. The main cause however, is probably related to micro tearing of the plantar fascia ligament and resultant abnormal scar formation within the body of the ligament.

Most patients present to their primary or specialty physician with the concern that they have identified a possible “tumor” on their foot. The location of the fibroma, its slow growth, and normal overlying soft tissue are clinical clues that the mass is a fibroma.  Treatment includes pressure relieving pads or customized orthotics to reduce pressure in the region of the soft tissue mass if pain is noted with walking.  The occasional use of cortisone injections into the fibroma can help reduce the size of the mass. Surgical biopsy is generally not recommended and can potentially make the mass size worse.  Surgical excision is recommended if pain is not relieved with padding or orthotic devices. Surgical excision must encompass the entire fibroma along with generous margins of the plantar fascia surrounding the fibroma. The generous margin of healthy plantar fascia will lessen the chance of fibroma recurrence which is the main complication associated with surgical excision.

Patient reassurance is sometimes the most difficult task when educating patients about the natural course of plantar fibroma. Patient re-evaluation after the initial clinical diagnosis is usually recommended if the plantar fibroma spreads to other areas of the ligament or if an increase in mass size or pain develops.