Pleuroparenchymal fibroelastosis from a consecutive database: a rare disease entity?

Pleuroparenchymal fibroelastosis (PPFE) is a rare condition characterised by predominantly upper lobe involvement with pleural fibrosis and subjacent parenchymal fibroelastosis [1, 2]. Idiopathic PPFE (IPPFE), which was included in the rare idiopathic interstitial pneumonias (IIPs) in the update of the international multidisciplinary classification of IIPs published in 2013 [3], was first described in the Japanese literature by Amitani et al. in 1992 [4]. PPFE has been reported to be associated with drugs, chronic hypersensitivity pneumonia, collagen vascular diseases, infections, and bone marrow transplantations [5–8]. However, the frequency of PPFE occurrence has been uncertain. We hypothesised that PPFE was not a rare disease entity and conducted this study. Informed consent was obtained from all patients, and the Institutional Review Board of the National Hospital Organization Kinki-Chuo Chest Medical Center (KCCMC) (Sakai City, Japan) approved this study. Idiopathic pleuroparenchymal fibroelastosis is an acceptable entity among IIPs and not as rare as previously reported