Pleuroparenchymal Fibroelastosis: Update on CT and Histologic Findings

Pleuroparenchymal fibroelastosis (PPFE) is an interstitial lung disease (ILD) characterized at CT by upper lobe-predominant pleural thickening and subpleural fibrosis and histologically by visceral pleural fibrosis and subpleural fibroelastosis. Although initially classified as a rare idiopathic interstitial pneumonia, many cases are related to known risk factors, particularly hematopoietic stem cell and lung transplant, or observed in association with other ILDs. This review summarizes the diagnostic criteria for PPFE and illustrates the CT and histologic manifestations, aiming to familiarize the radiologist with the range of findings suggestive of the diagnosis.