Pulmonary sequestration.

Pulmonary sequestration is an uncommon congenital abnormality in which nonfunctioning lung tissue is supplied by an anomalous systemic artery. Both the extralobar and intralobar forms probably develop from an accessory lung bud from the primitive foregut. Both forms are situated on the left side in about two-thirds of patients. The anomalous arterial supply usually originates from the descending thoracic aorta, and there may be a large left-to-left or left-to-right shunt through the sequestration. The sequestration may have a fistulous communication with the upper gastrointestinal tract. Congenital anomalies, particularly diaphragmatic hernia, are frequently associated with the extralobar form. Intralobar sequestration occasionally is an incidental finding on roentgenograms of the chest in an asymptomatic patient; however, the disorder is usually symptomatic and the most common presentation is recurrent pulmonary infection. Presentation may be characterized by gastrointestinal symptoms, congestive heart failure, hemoptysis or hemothorax. Extralobar sequestration is usually an incidental finding on routine roentgenograms of the chest or during the management of some other congenital anomaly. Infrequently, extralobar sequestration presents with symptoms similar to those seen with the intralobar form. Roentgenograms of the chest, upper gastrointestinal series and arteriography are the most helpful diagnostic aids. The usual treatment is resection of the sequestration by removal of only the sequestration in patients with the extralobar form and by lobectomy or segmental resection in patients with the intralobar form. The reported results of operation have generally been excellent.