Pulmonary sequestration is characterized by which finding?

Pulmonary sequestration is characterized by which finding?

• A. A collection of air within the pleural space
• B. A mass of functional lung tissue that communicates with the bronchial tree
• C. A mass of nonfunctional lung tissue that does not communicate with the bronchial tree and has separate blood supply from the aorta
• D. A normal lung segment with systemic blood supply

Answer: (C)

Pulmonary sequestration is defined by nonfunctional lung tissue that does not connect to the bronchial tree and receives its blood supply from the systemic circulation, usually the aorta. This combination—no airway communication and an aberrant systemic feeding vessel from the aorta—is what makes sequestration distinctive. Because the tissue isn’t ventilated through the normal bronchial passages, it doesn’t participate in gas exchange. Imaging often reveals a feeding artery arising from the aorta feeding the lesion, which helps confirm the diagnosis and differentiates it from regular lung tissue. Other descriptions don’t fit as well: a collection of air in the pleural space would be a pneumothorax, not sequestration; a mass of functional lung tissue that communicates with the bronchial tree would behave like normal or hyperfunctioning lung tissue; and a normal lung segment with systemic blood supply would be an unusual, non-physiologic finding since normal lung tissue is supplied by the pulmonary arteries, not systemic arteries.

Pulmonary sequestration is defined by nonfunctional lung tissue that does not connect to the bronchial tree and receives its blood supply from the systemic circulation, usually the aorta. This combination—no airway communication and an aberrant systemic feeding vessel from the aorta—is what makes sequestration distinctive. Because the tissue isn’t ventilated through the normal bronchial passages, it doesn’t participate in gas exchange. Imaging often reveals a feeding artery arising from the aorta feeding the lesion, which helps confirm the diagnosis and differentiates it from regular lung tissue.

Other descriptions don’t fit as well: a collection of air in the pleural space would be a pneumothorax, not sequestration; a mass of functional lung tissue that communicates with the bronchial tree would behave like normal or hyperfunctioning lung tissue; and a normal lung segment with systemic blood supply would be an unusual, non-physiologic finding since normal lung tissue is supplied by the pulmonary arteries, not systemic arteries.