A group of interstitial lung diseases with no known etiology. There are several entities with varying patterns of inflammation and fibrosis. They are classified by their distinct clinical-radiological-pathological features and prognosis. They include IDIOPATHIC PULMONARY FIBROSIS; CRYPTOGENIC ORGANIZING PNEUMONIA; and others.

Synonyms: Pneumonia, Idiopathic Interstitial, Idiopathic Interstitial Pneumonia, Interstitial Pneumonia, Idiopathic, Idiopathic Interstitial Pneumonias, Pneumonias, Idiopathic Interstitial, Interstitial Pneumonias, Idiopathic