Acquired unilateral pulmonary vein atresia in a 3-year-old boy.

While unilateral pulmonary venous atresia (UPVA) most commonly presents as an extremely rare late embryological defect resulting in complete occlusion or absence of the PV pathway, it may also be an acquired pathology. We present a 3-year-old boy who presented with mild respiratory distress. Neonatal echocardiographic investigations revealed normal mediastinal anatomy and pulmonary vasculature with a bicuspid aortic valve. However, follow-up Doppler investigation revealed a pulmonary artery size difference with minimal forward flow and reverse flow during diastole. Absence of the left pulmonary veins and the presence of collaterals draining to the innominate vein confirmed the diagnosis of acquired UPVA. Our case represents the first case of acquired UPVA in conjunction with a normally functioning bicuspid aortic valve. The Doppler flow patterns discussed might be of significant interest to pediatricians, cardiologists and imaging specialists. These findings suggest that acquired UPVA should be considered in the differential diagnosis of such patients when radiographic and echocardiographic findings may rule out other more common diagnoses. While the management of such a condition remains unclear and conservative management was agreed upon for our patient, the vulnerability of such cases warrants timely diagnosis and routine monitoring.