Korean Guidelines for Diagnosis and Management of Interstitial Lung Diseases: Part 4. Cryptogenic Organizing Pneumonia.

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. Pathologic manifestations include granulation tissues in the alveoli, alveolar ducts, and bronchioles. COP responds fairly well to glucocorticoid monotherapy with rapid clinical improvement, but recurrence is common. However, it is not recommended to combine immunosuppressant agents, even if the COP patient does not respond to glucocorticoid monotherapy with expert opinion.