Para-aortic extralobar pulmonary sequestration initially presenting as a posterior mediastinal lesion: a case report

Extralobar pulmonary sequestration is a rare congenital malformation characterized by nonfunctional lung tissue lacking communication with the tracheobronchial tree and receiving systemic arterial supply. Because of its unusual location and nonspecific imaging appearance, it may occasionally mimic a mediastinal tumor. A 66-year-old asymptomatic woman was referred after a left lower thoracic mass was incidentally detected during routine screening. Further imaging identified an aberrant systemic feeding artery arising from the descending thoracic aorta and venous drainage into the hemiazygos venous system, while three-dimensional reconstruction clarified the vascular anatomy for operative planning. After informed discussion of observation and surgical resection, the patient elected to undergo uniportal video-assisted thoracoscopic surgery. The lesion was completely separated from the normal lung and was resected after individual division of the feeding artery and draining vein. Histopathological examination confirmed extralobar pulmonary sequestration. The postoperative course was uneventful, and the patient remained asymptomatic at 6-month follow-up. Para-aortic extralobar pulmonary sequestration may present as a posterior mediastinal lesion on non-contrast CT. Contrast-enhanced CT can identify the anomalous systemic feeding artery and venous drainage, while three-dimensional vascular reconstruction provides clearer visualization of the vascular anatomy and assists thoracoscopic surgical planning.