Desquamative Interstitial Pneumonia
Differential Diagnosis
| Langerhans Cell Histiocytosis |
Desquamative Interstitial Pneumonia |
| Intra-alveolar macrophages only focally present |
Diffuse intra-alveolar macrophages |
| Temporal heterogeneity |
Temporally uniform |
| Focal or multifocal disease |
Diffuse disease |
| Numerous eosinophils |
Occasional eosinophils |
| Cystic change frequent |
No cystic change |
| Produces stellate scars |
Lacks scarring |
| Histiocytes with folded nuclei |
Histiocytes with round nuclei |
| Langerhans cells positive for CD1a and langerin |
Macrophages CD1a and langerin negative |
| Giant Cell Interstitial Pneumonia |
Desquamative Interstitial Pneumonia |
| Centrilobular distribution |
Diffuse intra-alveolar macrophages |
| Numerous multinodular giant cells |
Giant cells not present |
| Heavy metal may be identified |
No heavy metals |
| Usual Interstitial Pneumonia |
Desquamative Interstitial Pneumonia |
| Intra-alveolar macrophages only focally present |
Diffuse intra-alveolar macrophages |
| Temporal heterogeneity |
Temporally uniform |
| Architecture destroyed, honeycomb change prominent |
Architecture preserved, honeycomb change uncommon |
| Fibroblastic foci common |
Fibroblastic foci absent |
| Interstitial fibrosis marked |
Interstitial fibrosis mild to moderate |
| Interstitial fibrosis variably distributed |
Interstitial fibrosis tends to be more uniform |
Following steroid treatment, eosinophils may be harder to identify
| Post-obstructive Pneumonia |
Desquamative Interstitial Pneumonia |
| Foamy macrophages |
Finely granular macrophages |
| No pigment in macrophages (unless a smoker) |
Pigment in macrophages |
| No interstitial pneumonitis |
Interstitial pneumonitis present (but mild) |
| Localized |
Generalized |
- Infection must always be ruled out
- Especially important in immunosuppressed patients
- Atypical mycobacteria may simulate this pattern
- Asbestosis and drug reactions should be ruled out clinically and by searching for asbestos bodies
- Amiodarone may produce non-pigmented coarsley foamy macrophages
- Usually associated with organizing pneumonia or acute interstitial pneumonia
