You may be wondering, "What is this bump I have on the top of my foot?" It probably looks like it's filled with jelly and is making it difficult to wear shoes. What you may have is called a cyst.
Cysts are fluid-filled masses under the skin. Common cysts of the feet include synovial cysts, ganglia, and cutaneous mucoid cysts.
Most foot cysts are located under the skin, although occasionally they appear in tendon or bone. Synovial or ganglionic cysts are connected to a nearby joint or tendon, which makes them harder to treat. Mucoid cysts are not connected to a joint. Most cysts lead to mild pain as a result of the pressure created by wearing shoes. When any of these cysts enclose or press on a nerve, they can cause a sharp pain. X-rays, ultrasound, MRI, or CT scans are common methods for diagnosing cysts in the feet.
The best way to prevent cysts from forming is to wear well-fitted, comfortable shoes and avoid repeated foot injuries. Persistent ganglion cysts can be treated by numbing the area and extracting the fluid inside. A steroid or hardening agent may then be injected into the cyst to try to prevent it from filling again.
What Is A Ganglion Cyst?
A ganglion cyst is a sac filled with a jellylike fluid that originates from a tendon sheath or joint capsule. The word "ganglion" means "knot" and is used to describe the knot-like mass or lump that forms below the surface of the skin.
Ganglion cysts are among the most common benign soft-tissue masses. Although they most often occur on the wrist, they also frequently develop on the foot- usually on the top, but elsewhere as well. Ganglion cysts vary in size, may get smaller and larger, and may even disappear completely, only to return later.
Although the exact cause of ganglion cysts is unknown, they may arise from trauma, whether a single event or repetitive micro-trauma.
A ganglion cyst is associated with one or more of the following symptoms:
- A noticeable lump- often this is the only symptom experienced.
- Tingling or burning, if the cyst is touching a nerve.
- Dull pain or ache- which may indicate the cyst is pressing against a tendon or joint.
- Difficulty wearing shoes due to irritation between the lump and the shoe.
To diagnose a ganglion cyst, the foot and ankle surgeon will perform a thorough examination of the foot. The lump will be visually apparent and, when pressed in a certain way, it should move freely underneath the skin. Sometimes the surgeon will shine a light through the cyst or remove a small amount of fluid from the cyst for evaluation. Your doctor may take an x-ray, and in some cases additional imaging studies may be ordered.
There are various options for treating a ganglion cyst on the foot:
- Monitoring, but no treatment. If the cyst causes no pain and does not interfere with walking, the surgeon may decide it is best to carefully watch the cyst over a period of time.
- Shoe modifications. Wearing shoes that do not rub the cyst or cause irritation may be advised. In addition, placing a pad inside the shoe may help reduce pressure against the cyst.
- Aspiration and injection. This technique involves draining the fluid and then injecting a steroid medication into the mass. More than one session may be needed. Although this approach is successful in some cases, in many other the cyst returns.
When Is Surgery Needed?
When other treatment options fail or are not appropriate, the cyst may need to be surgically removed. While the recurrence rate associated with surgery is much lower than that experienced with aspiration and injection therapy, there are nevertheless cases in which the ganglion cyst returns.
If you have a cyst that you believe needs to be seen by a podiatrist, call one of our six locations: Rocky Hill CT, Bristol CT, Newington CT, Glastonbury CT, Middletown CT, and Kensington CT, and make an appointment with one of our four highly trained podiatrists: Dr. Jeffrey S. Kahn, Dr. Richard E. Ehle, Dr. Craig M. Kaufman, and Dr. Ayman M. Latif.