Cryptogenic organizing pneumoniaRadlex concept

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) [MeSH] Pathology.—Organizing pneumonia manifests as a histologic pattern characterized by loose plugs of connective tissue in the airspaces and distal airways. Interstitial inflammation and fibrosis are minimal or absent. Cryptogenic organizing pneumonia, or COP, is a distinctive clinical disorder among the idiopathic interstitial pneumonias (5), but the histologic pattern of organizing pneumonia is encountered in many different situations, including pulmonary infection, hypersensitivity pneumonitis, and collagen vascular diseases. Radiographs and CT scans.—Airspace consolidation is the cardinal feature of organizing pneumonia on chest radiographs and CT scans. In COP, the distribution is typically subpleural and basal (Fig 45) and sometimes bronchocentric (96). Other manifestations of organizing pneumonia include ground-glass opacity, tree-in-bud pattern, and nodular opacities (37). [Fleischner Society]