Follicular Bronchiolitis / Bronchitis
Differential Diagnosis
- Lymphocytic interstitial pneumonitis
- Extranodal marginal zone lymphoma
- Nodular lymphoid hyperplasia
- Chronic hypersensitivity pneumonitis
| Lymphocytic Interstitial Pneumonitis | Follicular Bronchiolitis |
|---|---|
| Predominantly T cell infiltrate | Prominent B cell follicles |
| Predominantly interalveolar | Predominantly peribronchiolar |
| Follicular Bronchiolitis | Extranodal Marginal Zone B Cell Lymphoma |
|---|---|
| Predominantly germinal centers | Monomorphous infiltrate |
| Involvement of pleura and cartilage rare | Pleura and cartilage may be involved |
| Dutcher bodies not seen | Dutcher bodies may be seen |
| Polyclonal | Monoclonal |
| Follicular Bronchiolitis | Nodular Lymphoid Hyperplasia |
|---|---|
| Scattered follicles around bronchioles | Numerous germinal centers form mass lesion or lesions |
| Follicular Bronchiolitis | Hypersensitivity Pneumonitis |
|---|---|
| Fibroplasia is not typically seen | Interstitial fibroblastic foci and intra-airway BOOP-like plugs usually present |
| No granulomas or giant cells | Granulomas and giant cells generally present but may be infrequent in late stage |
| No fibrosis | May develop peri-bronchiolar fibrosis with honeycomb change in later stage |
