A plantar fibroma is a mass of fibrotic tissue located on the bottom of the foot. They are most often found in the arch. The fibroma grows within the plantar fascia, a ligament that extends from the heel to the toes on the bottom of the foot.
Plantar fibromas are benign (noncancerous) lesions. They are more common in middle-aged males, but are not uncommon in women as well. When they first develop, there is little or no pain. They feel like a firm lump that may be painful when pressed on.
The fibroma can stay the same size or grow larger over time. It is not unusual for additional fibromas to develop too. They can be located on one or both feet. Less commonly, numerous fibromas will form, and this is referred to as Ledderhose disease. Treatment is typically the same no matter how many fibromas are present. Diagnosis is often done clinically via physical exam, but a biopsy or MRI may be used to further evaluate the cause of the lump. An MRI is helpful in ruling out other potential foot conditions such as a cyst, infection, tendinitis, tendon rupture, and tumor. Imaging studies will usually be done if the mass is increasing in size or pain.
The cause of plantar fibromas is unknown. Like many conditions, there may be a genetic component. There is a higher rate of occurrence in people of Northern European descent. Another theory is that injury to the plantar fascia promotes growth of the nodules. Others believe certain medications such as beta-blockers, vitamin C, and glucosamine encourage growth of collagen and fibrous tissue that leads to fibromas. Still others believe there may be a link between chronic medical conditions such as chronic liver disease, diabetes, alcohol abuse, and epilepsy and the development of plantar fibromas.
Plantar fibromas are often not painful when walking if they are small. Pain can occur when they are pressed on. If the fibroma is not enlarging, shoe modifications and custom orthotics may be used to relieve pain by removing pressure on the fibroma when walking.
Steroid injections may be used to help shrink the fibroma. I prefer to mix the steroid injection with another medication that helps increase the absorption of the steroid. The fibroma will often soften and be less painful afterward. Steroid injections do not get rid of the fibroma, but they can help the patient avoid surgery.
When conservative treatments fail to provide pain relief, the fibroma may be surgically removed. Fibromas are embedded within the plantar fascia, so a portion of the plantar fascia may be removed along with the fibroma. The plantar fascia helps support the arch, so an orthotic may be prescribed to prevent flattening of the arch. There is a high rate of recurrence after surgical removal so routine monitoring is recommended.
Dr. Katie Evans is a board-certified podiatrist and owner of Range Foot & Ankle in Virginia. She provides comprehensive foot and ankle care including surgical options and wound care. Learn more at www.rangefootandankle.com.