Isolated unilateral absence of the right pulmonary artery with hemoptysis in adulthood: a case report.

Background: Unilateral absence of the pulmonary artery (UAPA) is a rare congenital anomaly resulting from the failure of the sixth aortic arch to fuse with the pulmonary trunk during embryonic development. In the absence of any congenital cardiac anomalies, it is referred to as isolated UAPA. It is more often right-sided and may be asymptomatic until adult age. The literature regarding isolated UAPA in adults is limited. This paper aims to enhance understanding of UAPA in this age group and improve its management objectives. Case Description: We present a rare case involving a 37-year-old man with hemoptysis and slight stuffiness. Computed tomography angiography (CTA) revealed the absence of the right pulmonary artery, along with marked dilation of the bronchial, intercostal, inferior phrenic, internal mammary, and lateral thoracic arteries. These arteries were considered as collateral circulation to the right lung. As this was his initial instance of hemoptysis, he chose conservative treatment and was discharged after the symptoms improved. During the follow-up period, the patient has had no further episodes of hemoptysis or other related symptoms. Conclusions: Clinicians should consider isolated UAPA in adult patients with unexplained hemoptysis. CTA can confirm the diagnosis and discern the anatomic details, collateral arteries will also be depicted.