[A case of congenital absence of the right pulmonary artery]

A 14-year-old girl was admitted to ur hospital with pneumonia of the left lung, and some residual abnormalities were noted on chest X-ray film after recovering, which showed a small right hemithorax, displacement of the heart and mediastinal structures toward the right, and a small right hilum. There was no radioisotope accumulation in the right lung on pulmonary perfusion scintigraphy, and pulmonary angiography showed proximal interruption of the right pulmonary artery. Contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) confirmed the absence of the right main pulmonary artery and enabled congenital absence to be distinguished from acquired obstruction of the artery. The peripheral pulmonary arteries in the affected lung were identified on CT, and radioisotope angiography showed a blood supply to it from the systemic circulation. However, aortography and bronchial arteriography failed to show an aberrant systemic pulmonary artery. 133Xenon ventilation-perfusion scintigraphy showed that the ventilation of the affected lung was about 50% of that of the left lung, but there appeared to be no gas exchange by the affected lung. Her prognosis was expected to be good, because she had neither cardiovascular abnormalities nor had developed pulmonary hypertension.