They are often small (less than half an inch), but can grow steadily to reach sizes of two inches or more. Occurring as single or multiple lesions, plantar fibromas  typically present along the medial border of the plantar fascia. They are benign, and composed of dense, fibrous tissue found in the ligaments. Rapid-growing and multi-planar fibromas are considered plantar fibromatosis.

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.” These masses can be treated non-surgically; however, if they grow larger, or are a persistent source of discomfort, they should be removed surgically.

History

Patients with plantar fibromas will usually report that they “just noticed the mass one day.” As the mass gets larger, they may report increasing discomfort with prolonged standing. The first thing to look for, however,  is a foreign body reaction from previous penetrating trauma; it is the most common cause of benign tumour of the sole, (especially among diabetic patients).

Secondly, although uncommon, a malignant synovial sarcoma may cause a fast growing and painful lump on the sole of the foot.

Physical Examination

Plantar fibromas lumps are usually located on the inside of the arch of the foot, and usually feel smooth and rubbery. Though not generally tender to touch, they may become irritated with prolonged weightbearing.

Imaging Studies

X-rays are often negative, although if taken in such a way as to highlight the soft-tissues, an outline of a mass may be seen. Ultrasounds will show soft tissue, so are a good diagnostic. An MRI, however, is the most comprehensive scan to determine what is actually occurring.

 

Treatment

Non-Operative Treatment

Plantar fibromas are normally treated non-operatively, until they cause discomfort to the patient on a regular basis. Non-operative treatment includes:

• anti-inflammatory medications
• exercises
• shoe modifications
• use of soft-accommodating or well molded custom-made orthotics.

 

 

 

Injectable Medications

Much of the conservative treatment lacks direct supporting evidence-based medicine and studies to support its efficacy. Injections can shrink the fibroma, whereas excision surgery has a high recurrence rate, with increased potential for wound healing issues.

Injection is steroidal. However, patients may have a recurrence requiring one or more additional injections. Secondary effects are depigmentation, or temporary subcutaneous fat atrophy at the injection site.

Exercises

The condition can cause pain, especially when standing and walking. So individuals who participate in high intensity, repetitive activities such as running and jumping, and those with plantar fasciitis, are at the highest risk. Trauma or injury to the foot can also cause plantar fibromatosis.

Exercises for plantar fibroma should first be done under the supervision of a physical therapist, to ensure that they are being done correctly. Stretching, to loosen the muscles and soft tissue in the calf and arch of the foot, can help. In some cases, patients may need to wear a splint or brace while exercising, to help manage symptoms.

Operative Treatment

Operative treatment is typically avoided, due to both the high recurrence rate, and the difficulty with obtaining clear margins. It involves excising (cutting out) the mass. This tends to be done through an incision in line with the length of the foot. The mass is then sent to be examined by the pathologist to confirm the diagnosis.

 

 

Potential Complications of Surgery

Surgery to remove a plantar fibroma can be associated with the usual array of potential complications, including:

• Recurrence –  These lesions typically involve the overlying skin and dermis, as well as the plantar fascia, and obtaining clean margins is difficult. As a result, they have a high recurrence rate and in many cases, recur rapidly. Surgical margins should approach 2 cm. The recurrence rate is significantly higher for plantar fibromatosis and in revision cases.
•  Wound healing problems –  Wound complications are surprisingly common in this type of surgery, as the lesions typically involve the overlying epidermis and dermis. Patients should be aware that skin grafting may be necessary. The larger the mass, the greater the likelihood of a wound problem. A painful scar is always a possibility with surgery on the sole of the foot.
• Infection – Usually occurs in 2-5% of cases, although it may be higher if a wound problem develops.
• Nerve injury – 2-5% of patients may have injury or irritation to the nerve on the inside of the sole of the foot (medial branch of the plantar nerve).
• Blood clot (DVT) – These are quite uncommon unless there is a specific risk factor for blood clotting.
• Pulmonary Embolism – Potentially very serious, but very uncommon unless there is a specific risk factor for blood clotting

Your feet mirror your general health . . . cherish them!