An enterolith is a mineral concretion or calculus formed anywhere in the gastrointestinal system. Enteroliths are uncommon and usually incidental findings but, once found, they require at a minimum watchful waiting. If there is evidence of complications, they must be removed.
Look up enterolith or nidus in Wiktionary, the free dictionary.
An enterolith may form around a nidus, a small foreign object such as a seed, pebble, or piece of twine, that serves as an irritant. In this respect, an enterolith forms by a process similar to the creation of a pearl.
An enterolith is not to be confused with a gastrolith, which helps digestion.