Pulmonary Sequestration with a Descending Aorta-Sized Aberrant Artery

A 47-year-old man was referred for further evaluation after an abnormal shadow was detected on a chest X-ray during a routine health check-up.Computed tomography (CT) revealed a 35-mm protruding structure arising from the descending aorta, which was initially suspected for an aortic aneurysm.However, contrastenhanced CT demonstrated that the lesion was an aberrant systemic artery measuring 21 mm in diameter and 35 mm in length, originating from a 23-mm descending aorta.Three smaller peripheral branches were identified supplying the left S10 segment, with no connection to the pulmonary vein-findings consistent with intralobar pulmonary sequestration.No significant inflammatory changes were observed in the surrounding lung parenchyma.Although no guidelines exist for managing pulmonary sequestration in adults, large-caliber aberrant systemic arteries have been reported to undergo aneurysmal degeneration or dissection due to systemic arterial pressure. 1Given the abrupt change in the vessel diameter, surgical or endovascular intervention was considered; however, the patient declined both options as he remained asymptomatic.Non-contrast CT was performed every 6 months for the first 3 years and annually thereafter, using a standardized protocol with diameterbased measurements.At the 10-year follow-up, contrast-enhanced CT was additionally performed to evaluate for possible thrombosis.No change in vessel morphology was observed (Figures 1a andb).