Corns are a frequent problem affecting the foot. They are a natural response to pressure as the skin thickens up to safeguard itself from that pressure. At some stage this process goes wrong and gets so thick that it's painful. There is a unrelenting myth that corns have roots that they can carry on growing back from once you attempt to remove them. This is like the analogy of plants which re-grow from their roots if you chop the top of the plants off. This analogy continues to be applied to corns since they carry on growing back again, however they don't have roots to grow back from.
Corns are caused by pressure and a competent podiatric doctor can readily get rid of a corn. However, after the corn is removed if the pressure that caused it is still there then, obviously, it will come back. It grows back since the cause remains and not because the podiatrist left a root there for this to grow back from. That pressure could be from poor fitting footwear or from something like a hammer toe or bunion leading to greater pressure on an area. When the corn is under the foot, then the cause is elevated pressure on the area where the corn is, probably due to the way you walk.
The myth persists because they do return, so its essential to eliminate the cause at the same time the corn is removed. There is absolutely no root to be removed. This means that the pressure on the foot the location where the corn was really needs to be decreased or removed. This can involve issues like using better fitting shoes or the use of padding to get pressure off the location where the corn is. Sometimes surgery can be required to the bone beneath the corn to eliminate the pressure. If that cause is not removed or decreased then the corn will return, so it's easy to see where the myth concerning corn roots derives from.