Idiopathic pleuroparenchymal fibroelastosis in a patient with pectus excavatum: an overlooked association

Pleuroparenchymal fibroelastosis (PPFE) is a rare, progressive interstitial lung disease characterised by prominent upper lobe fibrosis and elastotic changes. Its aetiology remains unclear, with most cases classified as idiopathic. While pectus excavatum has been noted in some PPFE cases, its potential role in disease pathogenesis has not been explored. We report a 76-year-old Sri Lankan man diagnosed with idiopathic PPFE who also had pectus excavatum. He had no features of connective tissue disease, no history of prior infections or environmental exposure that could explain his condition. A literature review identified seven global cases of PPFE with pectus excavatum, none of which discussed a possible association. Six of these cases, including ours, were idiopathic. We propose that pectus excavatum can lead to chronic restrictive mechanics and upper lobe atelectasis and may play a role in PPFE pathogenesis rather than being an incidental finding. This case is the third reported case of PPFE in Sri Lanka and one of few worldwide, highlighting its potential association with pectus excavatum. Given that PPFE remains underdiagnosed, particularly in tuberculosis endemic regions, recognising such atypical risk factors may aid in earlier detection and management. Further studies are needed to determine whether pectus excavatum contributes to PPFE development or coexists as a structural abnormality.