Bronchiolocentric interstitial pneumonia is a more accurate interstitial lung disease classification than hypersensitivity pneumonitis: pro

Classification of interstitial pneumonias (also termed “interstitial lung disease” [ILD]) hinges on identifying distinct morphologic patterns on chest computed tomography (CT) or lung biopsy to suggest an underlying biology. The identified pattern is integrated with additional data to form a multidisciplinary diagnosis that guides management.1,2 The previous approach to the classification of ILD was updated by a recent European Respiratory Society/American Thoracic Society (ATS) Taskforce,3 which broadens the idiopathic-only framework to a comprehensive schema that incorporates both idiopathic and secondary disorders, introduces important new subcategories, and aligns terminology with biology and across disciplines. Together, these changes are intended to facilitate knowledge generation and improve patient outcomes. The 2013 classification discussed bronchiolocentric interstitial pneumonia (BIP) as a histopathologic pattern that may be idiopathic, but with uncertainty in whether such cases were variants of existing idiopathic interstitial pneumonias or occurred only with other causes (eg, hypersensitivity pneumonitis [HP], autoimmune disease).1,4 Expanding the updated classification beyond idiopathic entities mandated inclusion of the multiple causes of airway-centered ILD, but with debate among the taskforce committee on the optimal approach.