Extralobar pulmonary sequestration in the left superior mediastinum with an atypical pulmonary artery supply

Extralobar pulmonary sequestration is a rare congenital anomaly with a nonfunctional lung mass with no connection to the bronchial tree and a systemic arterial supply. Most cases are located in the lower thorax and involvement of the left upper thorax is exceedingly rare. We present a case of an incidental left superior mediastinal mass in an asymptomatic patient undergoing a screening chest radiography. Further chest CT revealed a large mass in the left superior mediastinum, with arterial supply from the left pulmonary artery. Surgical excision was performed, and histopathology demonstrated ectopic pulmonary tissue with its own pleura without bronchial connection. The case highlights the diagnostic challenges and surgical considerations in rare anatomical variations of pulmonary sequestration at the left superior mediastinum.