Ganglions  are a common cyst that can develop on the top or bottom of the foot.  They are not harmful or cancerous, although they may cause you some discomfort.

Ganglions are usually located on the ankle or top of the foot, but also occasionally form elsewhere on the foot. Ganglions are small fluid-filled swellings of the joint or tendon. They usually grow slowly, but can cause severe irritation when the size becomes too large.

Ganglions are usually caused by repeated irritation that weakens joint or tendon linings. If you wear boots or other restrictive footwear, you may be more susceptible to this condition. Individuals with bone spurs may also find that the pressure of these bony growths can cause ganglions as well.

If you are concerned that you may have a ganglion, it is very important to seek the opinion of a professional, as the appearance of a ganglion is similar to that of a tumor. The symptoms of this condition range from tingling and numbness, to severe pain. These sensations are caused when ganglions put excessive pressure on nerves within the foot. Treatment methods range from fluid removal, icing, or surgery, but the most common treatment is as easy as soft pads being placed around the ganglion, to reduce pressure and pain