Extensor Digitorum Brevis Ganglion Cyst

Mr Chin is an ardent 45 yrs old runner who plays badminton occasionally. Since 2 years ago he noticed a swelling on his right midfoot when he runs marathons or plays badminton more frequently. The swelling goes of after several weeks. I examined the swelling and found it to be non-tender, like a fluid-filled sac (cystic) and seem to arise from the fascia covering the Extensor Digitorum Brevis muscle (Inferior Extensor Retinaculum). This chap also has Hallux Valgus.

I told him that he could do an Ultrasound to confirm the diagnoses and a possible X-ray to rule out any bony anomaly which could cause the swelling. He was quite content as the swelling was usually painfree and decided to leave it alone for the time being.