Summary
Cryptogenic organizing pneumonia (COP) or bronchiolitis obliterans with organizing pneumonia (BOOP) is an inflammatory lung disease with distinctive clinical, radiological and pathological features. Men and women are affected equally and are usually aged between 50 and 60 years. The onset of symptoms is usually subacute with fever, nonproductive cough, malaise, anorexia and weight loss. Dyspnea is usually mild but is occasionally severe in some acute and life-threatening cases. No predisposing factors have been identified. In most cases, symptoms develop over a few weeks and the diagnosis of COP is made after 6 to 10 weeks. In COP, the organizing pneumonia is the most conspicuous pathological feature, examination of lung biopsy specimens shows intra-alveolar buds of granulated tissue consisting of fibroblasts, myofibroblasts, and loose connective tissue. The radiographic and computed tomography scan findings suggest the diagnosis when multiple patchy alveolar opacities with a peripheral and bilateral distribution are present. Video-assisted thoracoscopic lung biopsy is currently the preferred technique for diagnosing organizing pneumonia, because large lung specimens are necessary to make the diagnosis with confidence using other techniques. Transbronchial lung biopsy may show organizing pneumonia but does not allow the exclusion of associated disorders. Corticosteroids are the current standard treatment for COP. Response to this treatment is generally very good. *Authors: Prof. J-F. Cordier, Dr U. Costabel and Dr R. du Bois (October 2004)*.
