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A lump at the ankle can be due to a cyst, a hematoma, localized collection of fluid, a varicose vein causing venous pooling, arthritis or due to infection. First consult an orthopedic specialist and get an X-ray and or CT scan of the ankle. This will give a clear picture regarding the swelling.
Please let me know if there is any thing else and do keep me posted. Take care!
thanks so much for the advice. could it be possible that since it is at the site of the surgical scar that it could be a result of the surgery scar tissue?