The term “neuroma” means a “tumor of a nerve”. It is an abnormal growth of cells within a nerve, and the majority of them are benign, but a few rare tumors are cancerous. These true neuroma’s generally occur in the larger nerve trunks of the ankle and lower leg, and in other parts of the human body. They can occur in the smaller nerves of the foot, but this is very uncommon.
Over 100 years ago, a British physician named a benign tumor of the foot after himself and called it “Morton’s neuroma”. Modern medicine has shown that this tumor, which most often occurs between the bases of the 3rd and 4th toes, should be more accurately termed “perineural fibrosis” because it is a build up of scar tissue (fibrosis) around, not within, the small nerves between the metatarsal heads. This scar tissue becomes enlarged and causes compression on the nerve, which results in decreased blood and oxygen to the affected nerve segment, resulting in pain. This neoplasm or tumor can occur between any of the metatarsal heads of the foot.
Morton’s neuroma, or perineural fibrosis, is caused by local irritation of a segment of a nerve in the front part of the foot which rubs up against a thick ligament beneath the metatarsal heads. There is an initial inflammatory reaction resulting in scarring or fibrosis around the nerve segment. As this scarring enlarges, compression of the nerve segment occurs. Flat-feet, high arched feet, high heel shoes, narrow shoes, pointed shoes, and certain repetitive physical activities can result in the formation of a Morton’s neuroma. Frequently as this type of tumor enlarges, patients will experience pain and then remove their shoe and massage the foot, which will temporarily relieve the symptoms.
A proper history and physical examination by your Podiatric physician is necessary to be sure that the diagnosis is accurate. Other conditions such as arthritis, synovitis, tendinitis, metatarsalgia, or other types of tumors may mimic the symptoms of Morton’s neuroma. Certain diagnostic tests such as Ultrasound or an MRI may be necessary to clearly make the diagnosis of Morton’s neuroma. Traditional conservative medical treatments include changes or modifications of shoe gear, orthoses, injections, foot padding, and the use of anti-inflammatory medication. Many of these treatments will provide temporary relief, but since we have no way of reversing the scar tissue formation, then ultimately surgical treatment by a Podiatric surgeon may be necessary in order to alleviate the symptoms.