Swyer-James-Macleod Syndrome: The Differential Diagnosis of Unilateral Hyperlucency.

A 24-year-old male never-smoker who had no remarkable medical history presented to the emergency department with exacerbation of exertional dyspnea. Pulmonary auscultation demonstrated decreased breath sounds in the left lung. Chest X-ray showed hyperlucency in the left lung with air trapping during expiration (Picture 1A; inspiration, B; expiration). Chest computed tomography revealed a decrease in the density of the left lung, except for in the lingular segment (Picture 2), and hypoplasia of the left main pulmonary artery without any thrombus (Picture 3). A pulmonary function test revealed 4.11 L (82.5%) of forced volume capacity (predicted%) and 3.00 L (67.5%) of forced expiratory volume in 1 second (predicted%) without response to bronchodilators. He was diagnosed with Swyer-James-Macleod syndrome (SJMS). SJMS is a disorder characterized by constructive bronchiolitis-induced unilateral hyperlucency (1); however, SJMS can be easily overlooked. Therefore, it is important to consider the possibility of SJMS in order to accurately diagnose and treat patients with unilateral hyperlucency.

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The authors state that they have no Conflict of Interest (COI).