I have previously blogged about top of the foot bumps, Part 1 and Part 2. Prior posts addressed bony prominences (exostosis) causing bumps, but there can also be fluid filled cysts which arise from tendons or joints called ganglions, causing a bump.
Differentiation between the two can be determined by physical examination, x-rays, ultrasound and/or MRI. Typically, ganglions move beneath the skin whereas an exostosis does not. Fortunately, both conditions are benign, but if you have a bump on the top of your foot, you will still want to have it evaluated by a podiatrist.
Treatment for a ganglion include extracting the cyst fluid contents with a syringe, followed by steroid infiltration or surgical excision.
The following video shows an in-office surgical excision of a ganglion by my colleague, Dr. Anthony Nguyen.