Abstract
Cryptogenic organizing pneumonia (COP) is a type of idiopathic interstitial pneumonia with an acute or subacute clinical course. Bilateral lung consolidations located in the subpleural area and bronchovascular bundle are the most common findings on chest high-resolution computed tomography. The pathologic manifestations include granulation tissue in the alveoli, alveolar ducts, and bronchioles. COP responds fairly well to glucocorticoid monotherapy with rapid clinical improvement, but recurrence is common. However, treatment with combined immunosuppressant agents is not recommended, even if the COP patient does not respond to glucocorticoid monotherapy with expert opinion.