Representative findings of high-resolution computed tomography (HRCT) and surgical lung biopsy specimens of a patient with idiopathic pleuroparenchymal fibroelastosis (IPPFE). HRCT shows pleural thickening and subpleural consolidation opacities in the upper lobes (A). A lung section stained with hematoxylin and eosin shows subpleural fibrosis with an abrupt transition to normal lung parenchyma and fibroblastic foci, similar to that seen in usual interstitial pneumonia (B, ×12.5). Pleural fibrosis was also seen. A lung specimen with Elastica van Gieson staining demonstrates deposition of dense elastic fibers (elastosis) in a subpleural fibrotic lung lesion (C, ×12.5).