Ganglion cysts are common, fluid filled masses found under the skin. Filled with a jelly-like substance, a ganglion cyst can become larger or smaller from day to day. While many are painless, some can be the source of foot and ankle pain depending on whether the cyst is pushing on nerve or other sensitive tissue. The cyst can occur at numerous areas on the foot, although the most common locations are found on the top of the foot and the front of the ankle.

These balloon-like masses are derived from the tissue that covers a joint or tendon. When minor injury or chronic foot stress occurs, the joint or tendon tissue can buldge outward towards the overlying skin. This tissue has the purpose of creating lubricating fluid to allow tendons and joints to slide freely, and as the buldge occurs a thick fluid will fill up inside of it. The result is a fluid filled sac called a cyst. The cyst can range in size from very small to very large, and are seen through the skin as a compressible lump. They can be aggravated by shoes, and can be painful with weight bearing on the foot.

Treatment involves drainage with a needle, usually with the addition of a cortisone-like steroid injected afterwards to help shrink the cyst tissue and prevent reoccurrence. Unfortunately, many ganglion cysts have a high rate of return, and often require one or more excisional surgeries to permanently remove them. Surgery involves careful removal of the cyst and its surrounding tissue to ensure it is completely removed. Recovery is usually brief, and has few complications as long as the cyst has not wrapped itself around other tissue.