Thoracic foregut duplications.

Congenital duplications may arise anywhere in the gastrointestinal tract. Midgut duplications are the most common; foregut duplications (oesophagus, stomach, and the first and second part of the duodenum) account for approximately one third of all duplications. ' Foregut duplication cysts arise either as posterior mediastinal oesophageal duplications, or as foregut duplications from within the abdominal cavity and present as an abdominal mass, or extend through the diaphragm to lie within the thorax. These cysts often give rise to respiratory symptoms, though their mode of presentation is protean which presents diagnostic difficulties.2