There are several different causes of lumps and bumps on the top of the toes and foot. Working from the toes back these are:
1. Muco-Cutaneous Cyst
A small nodular single mass that can form on the top of a toe is called a Muco-Cutaneous Cyst. These occur most frequently at the joint just behind the toenail. These are caused by a weakening of the joint capsule, which allows a swelling to occur. They are firm and rubbery to the touch. Sometimes as the skin thins due to the stretching pressure of the mass it will appear translucent. When the mass is broken or punctured, a thick clear fluid will leak out. If the mass does break open, the area should be kept clean and free of infection. Once the skin heals the mass will reappear.
2. Treatment of Muco-Cutaneous Cysts
Treatment consists of surgical excision. This can be performed in the doctor's office under a local anesthesia or in an out patient surgery center. The procedure is relatively simple but can pose a problem for the surgeon, as closure of the skin following removal of the mass can be difficult. Often the surgeon will have to create a skin flap to rotate over the hole where the mass was removed. This requires a bit more of an incision than most patients expect. The foot is bandaged in a dry sterile dressing and the sutures remain in place for 7 to 10 days. The area must be kept dry during this period of time and a limitation of activity is advised. Complications associated with the surgery are infection, delays in healing associated with difficulty in surgically closing the wound or excessive activity which can lead to swelling and recurrence of the mass. Draining the mass as a form of treatment is not advised unless the patient is made aware of the likely recurrence. Picking the area open at home or attempting to drain it at home is discouraged. An infection in the area can cause joint damage or bone infection.
3. Hammertoe Deformity
Another prominence on the top of the toes is caused by hammertoe deformity. As the hammertoe forms, the toe cocks up and the joint in the middle of the toe becomes prominent. As the toe rubs on the top of the shoe a callus will form. Treatment consists of padding to reduce pressure or surgical straightening of the toe (See surgical correction of hammertoe).
4. Hallux Limitus
A lump can be found just behind the toe at the joint where the toe attaches to the foot. This is due to a prominence of the head of the metatarsal bone. It indicates that there is an alignment problem with the bones in the ball of the foot. The area may or may not cause a problem. If the lump is behind the big toe joint, it is a sign of a progressive arthritis of the joint. The condition is called Hallux limitus or degenerative arthritis. Treatment consists of orthotics to improve the function of the joint and/or surgical correction. (See surgical correction of hallux limitus).
5. Metatarsal-Cuniform Exostosis, Ganglion
Further up on top of the foot a bony prominence can form. This occurs near the middle of the foot and is due to the formation of bone spurs in the area. Jamming of two bones can over time, cause the spurring. The condition is named after the bones involved and is termed metatarsal –cuniform exostosis. On occasion, as the spurring forms, a weakening of the joint capsule occurs and a ganglion will form. A ganglion is a soft, rubbery mass, which slowly enlarges. Often the ganglion will form without a spur forming first. Treatment consists of padding the area to reduce the pressure from shoes or surgical removal of the bone spur and ganglion if present (See surgical correction of Metatarsal-cuniform exostosis).
Yet another area that can demonstrate a lump or bump on the top of the foot is an area just below the ankle on the outside of the foot. Normally there is a small fleshy area. This is the only muscle on the top of the foot called the Extensor digatorum brevis muscle. Some people have a larger muscle than others and the area may appear enlarged. The area may also enlarge if a lipoma or ganglion forms in this area. A MRI is a useful test to determine if a lipoma or ganglion is present. No treatment is recommended if there is no pain associated with the area.