Bronchogenic cysts are usually solitary unilocular cystic structures filled with either fluid or mucus and are usually attached to the trachea or major bronchi. Although they do not communicate with the foregut, they are thought to originate from an aberrant supernumerary bud of the developing foregut. The most common location is in the mediastinum above the tracheal bifurcation, but bronchogenic cysts may occur at the hilum of the lung or any paramidline site from suprasternal to infradiaphragmatic, and rarely have been reported in extrathoracic locations. Although usually associated with the extrapulmonary tracheobronchial tree, bronchogenic cysts may also be located within the lung parenchyma. In these cases, no connection to adjacent airways can be demonstrated, unless there is disruption of the wall due to secondary infection and necrosis. Because of localized compressive effects, the surrounding parenchyma may show obstructive changes including airspace enlargement but otherwise normal architecture. Bronchogenic cysts have been reported in association with congenital lobar overinflation, bronchial atresia, and extralobar sequestration.