A 57-year-old man was referred to our department because of progressive shortness of breath and emaciation. He had experienced pneumothorax three times in the past five years. The patient radiologically showed mild upper-lobe predominant airspace consolidation and severe platythorax and was clinically diagnosed with idiopathic pleuroparenchymal fibroelastosis (PPFE). Although the wedge-shaped shadows in the bilateral lung apexes did not significantly progress, his platythorax gradually worsened during the clinical course. He ultimately died of chronic respiratory failure 1.2 years after the diagnosis. This case demonstrates a rare variant of idiopathic PPFE with progressive platythorax disproportionate to the extent of upper-lobe fibroelastosis.