Foregut duplications are cystic or tubular malformations that arise from the cephalic segment of the primitive gastrointestinal tube. The foregut is an embryonic structure from which several respiratory and digestive structures originate: trachea, lungs, pharynx, esophagus, stomach, proximal duodenum, the parenchyma of the liver and pancreas. Most of these structures arise from the original tube as simple buds that then branch repeatedly. Foregut duplications are thought to be the result of abnormal additional buds that do not undergo a branching process and remain as simple blind cysts. They can occur at any level of the foregut, from the pharynx to the duodenum, but the vast majority develops from the tracheobronchial tree and the esophagus.