A discrete area of lung tissue that lacks any connection to the airway system and has abnormal blood supply arising from the aorta or its branches is called?

• A. Lung tissue connected to airway and normal blood supply
• B. Lobar pneumonia
• C. Pulmonary sequestration
• D. Lung cysts

Answer: (C)

This item tests recognizing a congenital lung anomaly defined by tissue that is isolated from the normal airway and receives blood from the systemic circulation rather than the pulmonary arteries. Pulmonary sequestration refers to a discrete area of lung tissue that lacks a connection to the bronchial tree and is fed by arteries arising from the aorta or its branches. This combination—no airway communication and systemic arterial supply—is the hallmark feature that sets sequestration apart from normal lung tissue, infections, or cystic structures. There are two forms (intralobar and extralobar) differing in pleural covering, but the essential concept remains the same: sequestered lung tissue, abnormal systemic blood supply, no airway connection. The other options describe tissue that either connects to the airway and has normal pulmonary blood supply, represents an infectious process, or consists of cystic structures, none of which match the defining features of pulmonary sequestration.