What is a ganglion cyst of the foot from?

It is a fluid : Filled sac, the contents are often gelatinous, it could arise from a joint, or tendon. Not sure, if we know exactly why they occur but they do. They are benign and treated when they become painful or are enlarging.

See below: Can occur from trauma or injury.

Same as wrist: A ganglion forms as a result of the synovial capsule between the bones of the joint. The inner synovial flud is extruded and then contained in a fibrous reaction which forms the cyst.

Same as the risks: There are not many problems associated with the wrists short of bony abnormalities. One common problem that can occur at the level of the wrists or coming from any joint is called a ganglion cyst. Ganglion cysts are not usually associated with much pain or discomfort until they become large. They extends from the joint space. It's, like blowing up a tiny balloon from between your knuckles. These often bust when a person bumps them. They will reoccur unless they are surgically tied off. I suggest you see an orthopedic surgeon to further assess and evaluate.

Ganglion cyst: If big and interfere with wearing shoes. Have it removed.

Surgery: If it causes a problem such as pain or issues with your shoes fitting comfortably then seek a good surgeon to remove it.