Certified GKH Gardening Expert
Did you experience this phenomenon? After some research, the general answer is that it is possible. Mostly what you'll find growing inside a potato is another potato. Normally, if a growing potato encounters a rock or foreign object, it will grow around it and accommodate it without enveloping it entirely. However, again, it's not impossible, but not likely. More often, the potato will become deformed or grow multiple protuberances around a foreign object.
Here's a more general article on growing potatoes. https://www.gardeningknowhow.com/edible/vegetables/potato/how-to-grow-potatoes-when-to-plant-potatoes.htm