Enomoto Y, et al. - An exploration was carried out of the pleural mesothelial cell-related markers in order to differentiate between pleuroparenchymal fibroelastosis (PPFE), usual interstitial pneumonia (UIP) and pulmonary apical cap (PAC). Data validated the use of immunofluorescence. On the other hand, immunohistochemical and morphological analysis did not yield any apparent difference between PPFE and PAC. Therefore, it was inferred that the presence of podoplanin-positive myofibroblasts could serve as a pathologic hallmark of PPFE, which hinted towards a pathogenic process distinct from UIP but common to PAC.