HI, This appears to be a ganglion cyst. Ganglion cysts are benign, harmless growths, but they will continue to enlarge at a slow rate and when they are big enough may cause pain during movement or by compressing nerves of the joint. You should take treatment for this. The commonest treatment is by draining the cyst with an injection and injecting hyaluronic acid into the cyst, this is a simple procedure which can be done at a clinic. Your doctor may also advise excision. You should look up these sites: http://www.emedicinehealth.com/ganglion_cyst/article_em.htm http://www.footphysicians.com/footankleinfo/ganglion-cyst.htm
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