A 4 years child presents with a history of chronic left lower lobe pneumonitis. On contrast bronchography, the area involved with the pneumonitis does not fill whereas the area around it does fill. The most likely diagnosis –

Sequestrated lung has no connection to airway, so this part does not fill on bronchography. Pulmonary sequestration In this congenital anomaly, there is a discrete mass of lung tissue without any normal connection to the airway system. It may be Intrapulmonary (intralobar) —> More common Extrapulmonary (extralobar) Sequestrated tissue receives its arterial supply from the systemic arteries (most commonly aorta). It returns blood to the right side of heart through IVC (extrapulmonary sequestration) or pulmonary veins (intrapuhnonary sequestration). The sequestration functions as a space-occupying lesion within chest, it does not function in gas exchange, and does not contribute to a left to right shunt or dead space. Gastric or pancreatic tissue may also be found in sequestrated segment. Associated anomalies —> cystic adenomatoid malformation, congenital diaphragmatic hernia, esophageal cysts.