Interruption of the right middle and lower lobe pulmonary arteries combined with arterial aneurysm formation at the origin of the right subclavian artery branch: a case report.

This paper reports a rare adult case of a 64-year-old female with interrupted pulmonary artery in the right middle and lower lobes, complicated by a branch aneurysm at the origin of the right subclavian artery. The patient was admitted for "depressed mood." And she experienced intermittent chest tightness and mild shortness of breath after physical activity. Elevated D-dimer levels were detected, and CT pulmonary angiography confirmed congenital interruption of the right middle and lower lobe pulmonary arteries, accompanied by extensive collateral circulation formation and pulmonary hypertension. This condition originates from abnormal development of the sixth aortic arch during embryogenesis and may clinically mimic chronic pulmonary embolism. Imaging evaluation is central to diagnosis, and treatment requires individualization: asymptomatic patients should undergo conservative follow-up, while those developing hemoptysis or progressive pulmonary hypertension may require interventional embolization or surgical intervention. This case underscores the need for vigilance regarding such rare vascular anomalies, where early recognition and long-term follow-up are crucial for improving patient prognosis.