Diffuse parenchymal infiltrates

For the staging of sarcoidosis, a system based on chest radiographs is in clinical use stage I consists of bilateral hilar adenopathy in stage II sarcoidosis, patients have bilateral hilar adenopathy and diffuse parenchymal infiltration stage III describes parenchymal infiltration without hilar adenopathy. Some authorities use a stage IV classification to indicate irreversible fibrosis. 

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