Bilateral Hyperlucent Lungs in an Adult: A Radiologic Approach

Background Swyer-James-MacLeod Syndrome (SJMS) is a rare, post-infectious obliterative bronchiolitis, typically presenting as a unilateral hyperlucent lung. Bilateral involvement is rare, with only pediatric cases reported to date. This case highlights an unusual bilateral presentation in an adult, which poses a significant diagnostic challenge. Case presentation: A 30-year-old non-smoking male with a history of recurrent childhood respiratory infections and chronic respiratory symptoms presented with persistent dyspnea. Initial chest radiography was unremarkable, but high-resolution computed tomography (HRCT) revealed bilateral hyperlucent lungs, decreased vascular markings, focal bronchiectasis, and cystic changes. Pulmonary function tests showed an obstructive pattern with a reduced FEV1/FVC ratio (36.79%), increased residual volume (172.6%), and gas trapping. Further workup excluded common differentials like alpha-1-antitrypsin deficiency, cystic fibrosis, and chronic thromboembolic disease. The constellation of findings led to a presumptive diagnosis of bilateral SJMS. Conclusions This case underscores the radiologic approach to bilateral hyperlucent lung in an adult and a presumptive case of SJMS, a finding previously unreported in the literature. It emphasizes the critical role of HRCT in diagnosis. Recognizing this rare presentation is essential to avoid misdiagnosis and guide appropriate conservative management, preventing unnecessary interventions.