Ganglions are a fluid-filled swelling of the lining of a joint or tendon that is most often formed on the ankle or top of the foot. However, Ganglions can form on any part of the foot and they usually grow very slowly.
There are often no symptoms for ganglions, but they put pressure on your nerves. Sometimes ganglions are accompanied by tingling, numbness or pain. Perpetual irritation to the ankle or top of the foot area can lead to ganglions through the weakening of the lining around a joint or tendon.
Ganglions can appear to be tumors and are sometimes mistaken as such. It is very important to consult a podiatrist if you believe that you may have a ganglion since they are very difficult to treat completely without surgery.