[Clinical pathologic classification of idiopathic interstitial pneumonia: review and perspectives]

The international classification of idiopathic interstitial pneumonia published in 2002 includes seven clinical-pathologic entities distinguished by their clinical features, aspect on high-resolution computed tomography, and histopathologic findings on lung biopsy. These seven entities are idiopathic pulmonary fibrosis (with features typical of interstitial pneumonia), nonspecific interstitial pneumonia, cryptogenic organising pneumonia, respiratory bronchiolitis with interstitial lung disease, desquamative interstitial pneumonia, lymphocytic interstitial pneumonia, and acute idiopathic interstitial pneumonia (with features of diffuse alveolar damage). This classification provides clearer diagnostic criteria for each entity, has fostered clinical research and therapeutic trials, and forms the basis for international guidelines on patient care. The classification is currently being revised in order to better integrate the recently identified syndrome of combined pulmonary fibrosis and emphysema, acute exacerbations of fibrosis, and new pathophysiologic and genetic findings.