by Jeffrey R. Carlson, MD
A ganglion cyst is a knot or lump that forms below the skin on either a joint or around a tendon. These cysts are filled with a thick, clear, jellylike fluid and can feel either firm or soft to the touch. The exact cause for the formation of a ganglion cyst is unknown; however, one theory is they arise from a trauma or injury that damages the joint tissue, while another points to a damaged joint capsule or tendon sheath. Ganglion cysts are benign and can appear as one large lump or several smaller cysts.
Symptoms of a ganglion cyst include:
- a visible mass that increases or reduces in size
- pain may or not be present
- weakness in the location of the cyst
The cysts are usually 1-3 cm in diameter and are soft, although some can be firm. Ganglion cysts do not move, but can change in size, and can even temporarily disappear completely. If the cyst touches a nerve, a tingling or burning sensation may be prevalent, while a sensation of pain may mean that the cyst is pushing on a tendon or joint.
Although many non-medically trained people may advise hitting a ganglion cyst with a book to cause it to rupture and go away, I would not recommend this course of action as it can lead to infection or other problems. Seeing a doctor is beneficial, even though many patients do not experience pain from a ganglion cyst.
A ganglion cyst can often be diagnosed by a physician by only a physical examination. Other diagnostic procedures may include using a needle to draw out a sample of the fluid from the cyst, ultrasound, and magnetic resonance imaging (MRI).
In most cases, no treatment is needed to remove the ganglion cyst or cysts. A physician will diagnose the cyst and simply monitor it for a period of time. If the ganglion cyst causes pain or makes it difficult to wear shoes, then a physician may suggest a wearing a specific shoe or the addition of a pad to the inside of the shoe to reduce pressure on the cyst.
An alternative treatment includes aspiration (removal of the fluid within the cyst by a needle) and injections of steroid medications. This may be repeated several times and the cyst may return after treatments.
If other methods prove ineffective, or if the ganglion cyst or pain associated with it inhibits the use of the foot, surgery may be needed to remove the cyst and the stalk of the cyst (a smaller tube through which fluid passes into the cyst). The surgery is almost always performed on an outpatient basis and can be done in-office under local anesthesia, twilight sedation or in an ambulatory surgery center under a nerve block or general anesthesia.
After surgery, the patient may wear a splint to restrict movement of the foot for 7-10 days. The use of crutches may be necessary to allow the foot to heal properly. Sutures will need to be kept dry and the incision covered. The need for follow up appointments and physical therapy depends on the patient and their specific condition. Risks of surgery include infection, scarring and recurrence. Full recovery is extremely likely.
Since we don’t know why they form, prevention of a ganglion cyst is impossible. Although ganglion cysts are harmless and may go away on their own, it is recommended that they be diagnosed and treated early.