Pulmonary sequestration is a developmental anomaly characterized by nonfunctional pulmonary parenchyma without normal connection to the tracheobronchial tree, supplied by an anomalous systemic artery (most commonly originating from the descending thoracic or upper abdominal aorta). Two types are described: intralobar sequestration (75%, located within normal pleura, typically left lower lobe posterobasal segment, drains via pulmonary veins, often presents in adolescents and adults with recurrent infection) and extralobar sequestration (25%, has its own pleural envelope, frequently below the left lower lobe or in the diaphragm/abdomen, drains via systemic veins, typically diagnosed in infants with respiratory distress and frequently associated with congenital diaphragmatic hernia, congenital cystic adenomatoid malformation, and other anomalies).
Clinical presentation in intralobar disease includes recurrent lower lobe pneumonia, productive cough, hemoptysis, lung abscess, and chronic chest pain; the systemic feeding artery can rupture causing massive hemoptysis. Extralobar sequestration in infants presents with respiratory distress, cyanosis, and feeding difficulties. Many cases are detected incidentally on CT or MRI performed for unrelated reasons. Diagnosis requires demonstrating an anomalous systemic feeding artery with CT angiography, MR angiography, or conventional angiography.
Surgical resection (segmentectomy or lobectomy via VATS or thoracotomy) is the treatment of choice for intralobar sequestration to eliminate the source of recurrent infection and risk of hemoptysis. Extralobar sequestration is removed when symptomatic or large; small asymptomatic lesions in adults can be observed. Endovascular embolization of the feeding artery (often via percutaneous coils) is an alternative or adjunct in selected adult cases or when surgical risk is high. Preoperative angiographic mapping of the systemic artery is essential to avoid catastrophic intraoperative bleeding.