In adults with an idiopathic interstitial pneumonia (IIP), an updated classification system was published in 2013. Although definitions for the seven histological patterns remain essentially unchanged, there has been substantial progress in our understanding. In relation to usual interstitial pneumonia (UIP), updated management recommendations were published in 2011, with the most significant change recommending varying degrees of confidence in diagnosis. A pattern of UIP is also being increasingly recognised in patients with chronic hypersensitivity pneumonitis. Idiopathic non-specific interstitial pneumonia is now better defined as a specific clinico-pathological entity, with the majority cases proving to have secondary associations/causes after multidisciplinary review. Respiratory bronchiolitis–interstitial lung disease is now commonly diagnosed without surgical biopsy, and acute exacerbation of IIPs is now well defined. A group of rare entities, including pleuroparenchymal fibroelastosis and rare histological patterns, is also introduced. There have also been advances in the undertaking of biopsies with most institutions sampling at least two sites, ideally using preoperative targeting. These histological patterns are also recognised in children, although classification is more complex and includes entities specific to a younger age group (e.g., neuroendocrine hyperplasia of infancy, pulmonary interstitial glycogenosis). Surfactant protein gene mutations are also being increasingly identified. In adults with an idiopathic interstitial pneumonia (IIP), an updated classification system was published in 2013. Although definitions for the seven histological patterns remain essentially unchanged, there has been substantial progress in our understanding. In relation to usual interstitial pneumonia (UIP), updated management recommendations were published in 2011, with the most significant change recommending varying degrees of confidence in diagnosis. A pattern of UIP is also being increasingly recognised in patients with chronic hypersensitivity pneumonitis. Idiopathic non-specific interstitial pneumonia is now better defined as a specific clinico-pathological entity, with the majority cases proving to have secondary associations/causes after multidisciplinary review. Respiratory bronchiolitis–interstitial lung disease is now commonly diagnosed without surgical biopsy, and acute exacerbation of IIPs is now well defined. A group of rare entities, including pleuroparenchymal fibroelastosis and rare histological patterns, is also introduced. There have also been advances in the undertaking of biopsies with most institutions sampling at least two sites, ideally using preoperative targeting. These histological patterns are also recognised in children, although classification is more complex and includes entities specific to a younger age group (e.g., neuroendocrine hyperplasia of infancy, pulmonary interstitial glycogenosis). Surfactant protein gene mutations are also being increasingly identified.
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Mar 1, 2016
M Urgamal 
Open Access
