Cryptogenic organizing pneumonia

Cryptogenic organizing pneumonia
Other namesBronchiolitis obliterans with organizing pneumonia, idiopathic interstitial pneumonia
Micrograph showing a Masson body (off center left/bottom of the image – pale circular and paucicellular), as may be seen in cryptogenic organizing pneumonia. The Masson body plugs the airway. The artery associated with the obliterated airway is also seen (far left of the image). H&E stain.
SpecialtyPulmonology 
Symptomscough, labored breathing, fever, fatigue, unexpected weight loss

Cryptogenic organizing pneumonia (COP), formerly known as bronchiolitis obliterans organizing pneumonia (BOOP), is an inflammation of the bronchioles (bronchiolitis) and surrounding tissue in the lungs. It is a form of idiopathic interstitial pneumonia.

It is often a complication of an existing chronic inflammatory disease such as rheumatoid arthritis, dermatomyositis, or it can be a side effect of certain medications such as amiodarone. COP was first described by Gary Epler in 1985.

The clinical features and radiological imaging resemble infectious pneumonia. However, diagnosis is suspected after there is no response to multiple antibiotics, and blood and sputum cultures are negative for organisms.