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cryptogenic organizing pneumonia

Wednesday 4 May 2005

COD, idiopathic BOOP, idiopathic organizing pneumonia, cryptogenic bronchiolitis obliterans with organizing pneumonia

Definition: Organizing pneumonia is a non-specific pathological reaction pattern to a diverse variety of agents of injury.

The organizing pneumonia pattern may be seen in organizing diffuse alveolar damage, organizing infections, organization distal to airway obstruction, aspiration, drug reactions, fumes, and toxic exposures, collagen vascular disease, hypersensitivity pneumonitis, eosinophilic lung disease, inflammatory bowel disease, as a secondary reaction in chronic bronchiolitis, and as a reaction around other processes (abscess, neoplasm, and others).

In the absence of a known cause or association the diagnostic term cryptogenic organizing pneumonia (COP), is used.

Although COP is currently classified as one of the idiopathic interstitial pneumonias, it is primarily characterized by alveolar and terminal airways filling with fibroblasts and immature connective tissue combined with interstitial inflammation and expansion of alveolar walls producing nodular areas of lung consolidation often centered on bronchovascular bundles.

A previous term for this condition was "bronchiolitis obliterans organizing pneumonia" (BOOP). This terminology emphasized the terminal airway obstruction component which varies in prominence from case to case and may be rare or absent in some cases.

Foci of obstructive pneumonia are often seen distal to obstructed terminal airways.


- cryptogenic organizing pneumonia (COP) at the Yale Rosen Collection