Asymptomatic Pulmonary Fibrosis Associated With Ipsilateral Proximal Interruption of a Pulmonary Artery (PIPA)

Pulmonary fibrosis is a chronic condition typically affecting both lungs; however, cases of unilateral pulmonary fibrosis are exceedingly rare and often result from specific unilateral inflammatory conditions like radiation pneumonitis or infection. An even rarer occurrence is the unilateral proximal interruption of a pulmonary artery (PIPA), a developmental anomaly resulting from the failed connection of the sixth aortic arch to the pulmonary trunk. This condition can manifest alone or alongside other cardiac abnormalities. There are limited reports of pulmonary fibrosis associated with PIPA. In this case, a 33-year-old male with chronic mild asthma presented with bilateral shoulder pain. Initial radiographs showed reticular opacities and volume loss in the right lung with a rightward mediastinal shift, suggesting possible fibrosis. Further investigations with chest Computed Tomography (CT) and CT angiogram confirmed right-sided pulmonary fibrosis and the absence of the right pulmonary artery, with no other significant cardiopulmonary symptoms reported. This case highlights the complexity of diagnosing and managing rare unilateral pulmonary conditions.