A 50-year-old man presented with a 3-year history of dyspnea on exertion and recurrent pulmonary infections. He had a history of exanthematous fever in childhood. Physical exam revealed rhonchi in both lung fields. Chest X-ray showed a hyperlucent right lung with pulmonary oligemia and a small hilum. HRCT revealed air trapping and bronchiectatic changes. CT pulmonary angiography showed decreased size of the right pulmonary vessels with no evidence of thromboembolism. Spirometry showed obstructive airway disease with reversibility. Bronchoscopy showed a normal tracheobronchial pattern. Based on these findings, the patient was diagnosed with adult Swyer James Mac