Tracheal agenesis.

Tracheal agenesis is a rare anomaly that produces neonatal respiratory distress and has been uniformly lethal to date. In this malformation the entire trachea is usually absent, air reaching the bronchi through a communication with the esophagus, and the lungs are normally formed. The diagnosis should be suspected in any infant in whom improved ventilation is obtained despite difficult intubation and abnormal tracheal tube placement. Coexistent cardiac, gastrointestinal, and genitourinary anomalies are common. The growth of the tracheoesophageal septum and the elongation of the dividing foregut are crucial phases in the morphogenesis of this malformation.