Unilateral absence of pulmonary artery associated with contralateral lung cancer

Unilateral absence of a pulmonary artery (UAPA) is a rare congenital cardiac malformation that is often associated with other cardiovascular deformities. Surgical repair of this rare condition is usually performed only on the abnormal lung. The occurrence of lung cancer in association with UAPA is even rarer and clinical experience is very limited. This report aims to describe a case of unilateral absence of right pulmonary artery that was complicated by primary carcinoma of the contralateral lung. A left lower lobectomy was performed despite the absence of the right pulmonary artery and repeated decreases in the arterial oxygen saturation (SaO₂) were encountered intraoperatively. The current case provides insights into the operative tolerability and the foreseeable ominous prognosis after excision of the normal lung in patients with UAPA and highlights the importance of the clinical awareness of this potentially lethal congenital anomaly in light of its extreme rarity, which may facilitate better diagnosis and treatment of such patients.