Corns are a common problem affecting the foot. They are a natural reaction to pressure as the skin thickens up to safeguard itself from that pressure. At some stage the process fails and becomes so thick that it's painful. There is a continual myth that corns have roots which they keep growing back from once you try to take them out. This is just like the analogy of plants that re-grow from their roots if you cut the top of the plants off. That analogy continues to be applied to corns as they keep growing back, but they do not possess roots to grow back from.
Corns develop from pressure and a skilled podiatric doctor could easily remove a corn. The problem is that after the corn is taken off if the pressure that caused it is still there then, of course, it is going to grow back. It comes back because the cause is still there rather than because the podiatrist left a root there for it to grow back from. That pressure might be from poor fitting footwear or from something like a hammer toe or bunion that leads to increased pressure on an area. When the corn is under the foot, then the cause is greater pressure on the spot where the corn is, probably due to the way you walk.
The myth remains because they do come back, so its essential to get rid of the cause when the corn is removed. There isn't any root to be extracted. This means that the pressure on the foot where the corn was should be lowered or removed. This will involve issues like using better fitting footwear or the use of padding to get pressure off the location where the corn is. Occasionally surgery is going to be required to the bone under the corn to get rid of the pressure. If that cause isn't eliminated or decreased then the corn will come back, so it's easy to see where the myth concerning corn roots originates from.