Classification and recent advances in idiopathic interstitial pneumonia.

Abstract

Idiopathic interstitial pneumonia (IIP) is a heterogeneous group of diseases comprising acute interstitial pneumonia, bronchiolitis obliterans organizing pneumonia (BOOP), nonspecific interstitial pneumonia, desquamative interstitial pneumonia, and idiopathic pulmonary fibrosis and usual interstitial pneumonia (IPF/UIP). We review the clinicopathological spectrum of IIP and introduce recent advances in classification, treatment, and prognosis. BOOP can be clinically categorized as an interstitial pneumonia, though prominent granulation tufts are seen in the airspaces. Though differences between the nonspecific interstitial pneumonia and other lips can be histopathologically clarified, the focus of clinical research on NSIP is differentiation from BOOP, or from IPF and UIP. IIP can be categorized into two groups: groups with acute or subacute lung injuries or fibrosis, such as in acute interstitial pneumonia, BOOP and nonspecific interstitial pneumonia, and groups with chronic injuries or fibrosis, such as IPF/UIP. This classification accords well with the maturity of fibrosis, CT findings, bronchoalveolar lavage fluid cell findings, and prognosis. The most critical problem is the treatment of IPF/UIP, because of its high mortality.