An Atypical Surgical Case of Lung Cancer With Unilateral Absence of the Pulmonary Artery, With Only the Superior Branch Remaining.

A 69-year-old woman was referred to our department for an abnormal shadow on chest radiography. Contrast-enhanced computed tomography (CT) revealed a solid nodule in the right lower lobe and defects in the branches of the middle and lower lobes of the pulmonary artery (PA). Furthermore, collateral circulation had developed via the right internal thoracic, bronchial, intercostal, inferior phrenic, and subdiaphragmatic arteries. The solid nodule was diagnosed as adenocarcinoma by CT-guided biopsy. The day before surgery, embolization was performed using interventional radiology (IVR) to mitigate the risk of bleeding during thoracotomy, resulting in minimal intraoperative bleeding during the subsequent right middle and lower lobectomies with lymph node dissection (ND2a-1). UAPA is a rare congenital abnormality characterized by unilateral pulmonary artery agenesis. The presence of recurrent infections, extensive intrathoracic adhesions, and developed collateral circulation may pose challenges during surgical procedures.