Dieulafoy's lesion (or Dieulofoy lesion) is a medical condition characterized by a large tortuous arteriole most commonly in the stomach wall (submucosal) that erodes and bleeds. It can present in any part of the gastrointestinal tract. It can cause gastric hemorrhage but is relatively uncommon. It is thought to cause less than 5% of all gastrointestinal bleeds in adults. It was named after French surgeon Paul Georges Dieulafoy, who described this condition in his paper "Exulceratio simplex: Leçons 1-3" in 1898. It is also called "caliber-persistent artery" or "aneurysm" of gastric vessels. However, unlike most other aneurysms, these are thought to be developmental malformations rather than degenerative changes.