Nonspecific Interstitial Pneumonia
Differential Diagnosis
NSIP is a diagnosis of exclusion
- Usual Interstitial Pneumonia
- See table below
- Acute Interstitial Pneumonia
- Both are temporally uniform and have interstitial inflammation
- Hyaline membranes and intra-alveolar organization should not be seen in NSIP
- Desquamative Interstitial Pneumonia
- Both are temporally uniform
- Predominant desquamative pattern should not be seen in NSIP
- Cryptogenic Organizing Pneumonia
- BOOP-like changes may be seen focally but do not predominate in NSIP
- COP has less interstitial inflammation
- Lymphocytic Interstitial Pneumonia
- Interstitial lymphoid infiltrate is more pronounced in LIP but cutoff is not well defined
- Respiratory Bronchiolitis Associated Interstitial Lung Disease
- Bronchiolocentric distribution in RBAILD
- Generally uniform involvement in NSIP
- Hypersensitivity Pneumonitis
- Granulomas and peribronchiolar distribution should not be seen in NSIP
Infection must be ruled out in every case
| Usual Interstitial Pneumonia | Nonspecific Interstitial Pneumonia |
|---|---|
| Temporal and spatial heterogeneity | Temporal and spatial uniformity |
| Honeycomb change prominent | Honeycomb change rare |
| Scant interstitial inflammation | Prominent interstitial inflammation |
| Prominent fibroblastic foci | Fibroblastic foci few, focal |
