Congenital and miscellaneous abnormalities
Bronchobiliary fistula (BBF) is a rare condition characterized by communication between the tracheobronchial and biliary ductal systems. When BBF occurs, it typically is associated with trauma, cancer, or liver infection, although congenital BBF has been described. Cast, or plastic, bronchitis is a potentially fatal disorder seen relatively rarely in children. It derives its name from mucoid material which forms within the tracheobronchial tree in the form of a branching tubular cast of the airway. It characteristically has a rubbery consistency. These may be expectorated piecemeal or removed at bronchoscopy as extensive casts of the airway. Congenital diaphragmatic hernia (CDH) describes an inborn defect in the diaphragm that allows protrusion of abdominal fat and/or viscera through the opening into the thoracic cavity. The cause of this defect is not fully understood and likely is multifactorial. Patients with diaphragmatic hernias suffer from severe, often lethal, pulmonary hypoplasia. In addition to the startlingly high mortality despite medical advances, short- and long-term morbidity is significant. Primary hepatopulmonary fusion is an extremely rare condition in patients with a right-sided CDH, in which there is a fusion between the right lung and the herniated liver parenchyma through a defect in the diaphragm. There may be varying degrees of pulmonary hypoplasia associated with this condition. In horseshoe lung, the posteroinferior bases of the right and left lungs are fused by a narrow band of normal lung tissue referred to as an isthmus without an intervening pleural fissure. The isthmic portion of the horseshoe lung originates from the hypoplastic sides of lung; it is located posterior to the heart, but anterior to the aorta and to the esophagus. The blood supply for the isthmus usually originates from the right pulmonary artery and is aerated by a bronchial extension from the right bronchus.