Abstract Introduction Swyer-James-MacLeod syndrome (SJMS) is a rare, acquired pulmonary disorder characterized by unilateral hyperlucency of the lung, typically resulting from post-infectious bronchiolitis obliterans in childhood. The syndrome often presents with recurrent respiratory infections, chronic cough, and exertional dyspnea, but may be diagnosed incidentally in adulthood. Radiologic findings include reduced lung volume, diminished vascular markings, and air trapping, with or without bronchiectasis. Recognition of SJMS is critical to avoid misdiagnosis and inappropriate management, as the condition may mimic asthma, pulmonary embolism, or pneumothorax. Case Presentation A 32-year-old male (transitioned female to male) with a history of extreme prematurity (born at 26.5 weeks, 2 lb 7 oz) and likely patent ductus arteriosus ligation in the neonatal period was referred for evaluation of abnormal chest CT. He reported recurrent pneumonia since childhood, including a recent hospitalization for pneumonia with parapneumonic effusion, hypoxemia, and persistent ground-glass opacities and interlobular septal thickening on CT. Additional history included frequent bronchitis episodes. Physical examination revealed mild exertional dyspnea without clubbing or cyanosis. Pulmonary function testing showed mild obstructive changes. Chest radiograph demonstrated unilateral hyperlucency and reduced lung volume. High-resolution CT confirmed unilateral areas of decreased attenuation, air trapping, interlobular septal thickening, and patchy ground-glass opacities. Bronchiectasis was present in the affected lung, with no evidence of central bronchial obstruction or cystic lesions. Discussion Swyer-James-MacLeod syndrome (SJMS) is a rare, acquired disorder resulting from post-infectious bronchiolitis obliterans, typically manifesting as unilateral hyperlucency, reduced lung volume, and diminished vasculature on imaging. Adult patients may present with recurrent respiratory infections, chronic cough, exertional dyspnea, or be diagnosed incidentally. Bronchiectasis and emphysematous changes are common, and the disease can be confused with asthma or pulmonary embolism, leading to delayed or inappropriate management. Long-term outcomes in SJMS are generally favorable, with most adults experiencing stable lung function and minimal progression. Inhaled corticosteroids, long-acting beta agonists, vaccination, and airway clearance techniques are effective in reducing symptoms and preventing infections for many patients. However, a subset may develop progressive pulmonary dysfunction, severe emphysema, or bullous disease, sometimes necessitating surgical intervention such as lobectomy or pneumonectomy. Surgical resection is reserved for those with refractory symptoms, recurrent infections, or significant functional compromise, and can result in improved symptoms and lung function. This case underscores the importance of recognizing SJMS in adults, differentiating it from other causes of unilateral lung disease, and applying evidence-based monitoring and management strategies to optimize long-term outcomes. This abstract is funded by: None
Klingel et al. (Fri,) studied this question.