Cryptogenic Organizing Pneumonia - Bronchiolitis Obliterans Organizing Pneumonia
Differential Diagnosis
| Usual Interstitial Pneumonia |
Cryptogenic Organizing Pneumonia |
| Temporal heterogeneity |
Temporally uniform |
| Honeycomb change prominent |
Honeycomb change rare |
| Interstitial fibrosing process |
Intralumenal fibrosing process |
| Fibroblastic foci adjacent to mature collagen, covered by epithelium |
Granulation tissue foci without significant collagen, not subepithelial |
| Random distribution |
Bronchiolocentric distribution |
| Predominantly collagenous fibrosis |
Predominantly fibroblastic fibrosis |
Organizing pneumonia may be seen focally in UIP or in the setting of acute exacerbation of UIP
BOOP pattern may be seen in acute eosinophilic pneumonia
- Specific causes of organizing pneumonia pattern must always be ruled out
- These include infection, toxins, drugs, radiation, inflammatory bowel disease
- Organizing pneumonia pattern may be superimposed on a chronic process such as UIP
in the setting of an acute exacerbation
- Presence of more than rare intra-airway granulation tissue plugs should suggest COP/BOOP
- Clinical and radiographic history is important
