Kono M, Nakamura Y, Enomoto Y, et al. - In this retrospective multicenter study, researchers investigated the cumulative incidence, clinical features, and risk factors of pneumothorax in patients with idiopathic pleuroparenchymal fibroelastosis (PPFE). Among 89 identified patients who had been diagnosed with idiopathic PPFE, 53 (59.6%) developed pneumothorax with 120 events during the observation period (41.8 ± 35.0 months). At 1, 2, and 3 years, the cumulative incidence of pneumothorax was 24.8%, 44.9%, and 53.9%, respectively. In multivariate analysis, a higher residual volume/total lung capacity ratio was identified to be significantly linked with the development of pneumothorax after the diagnosis. Findings revealed that in these patients, pneumothorax is often asymptomatic and recurrent, resulting in poor outcomes in some cases.