A disease formerly considered a form of interstitial pneumonia. Its etiology is obscure but it may be associated with toxic fumes, infection, and connective tissue disease. Clinical symptoms include cough, dyspnea and influenza-like symptoms with the development of the usual interstitial pneumonia in many cases. Obstructive symptoms are limited to smokers. There are patchy polypoid masses of intra-alveolar granulation tissue in small airway lumina and alveolar ducts. "Organizing" refers to unresolved pneumonia (in which the alveolar exudate persists and eventually undergoes fibrosis) in which fibrous tissue forms in the alveoli. (From Segen, Dictionary of Modern Medicine, 1992; Stedman, 25th ed).