Long-Term Follow-Up of Pleuroparenchymal Fibroelastosis Associated With Crohn's Disease.

Pleuroparenchymal fibroelastosis (PPFE) is a rare fibrosing interstitial lung disease that has been increasingly reported as a secondary condition following various underlying disorders including organ transplantation. However, reports on PPFE associated with inflammatory bowel disease (IBD), such as ulcerative colitis and Crohn's disease, remain extremely limited. We report the case of a 70-year-old man with Crohn's disease who developed slowly progressive upper-lobe-predominant lung lesions. Based on the clinical course, including the development of platythorax and pneumomediastinum, as well as the characteristic pulmonary function impairment and radiological findings, the patient was clinically diagnosed with PPFE. PPFE secondary to Crohn's disease is exceedingly rare, and this case is valuable in that longitudinal radiological progression could be followed in detail. This case highlights the importance of recognising PPFE as a pulmonary complication of Crohn's disease and underscores the value of careful longitudinal assessment using serial imaging and pulmonary function tests.