Comparison of the lung cystic lesions between Birt–Hogg–Dubé syndrome (BHD) and blebs/bullae
| BHD (primary cyst) | BHD (modified cyst) | Idiopathic blebs and bullae | |
|---|---|---|---|
| Location | Lower lobes/perimediastinum | Lower lobes/perimediastinum | Upper lobes/apex |
| Number | A few to multiple | A few to multiple | One or a few |
| Basic structure | Alveolar cysts/partially fused to pleura | Elongated pleura/alveolus or a few alveoli within a cyst | Intrapleural and/or parenchymal air spaces/destructed alveoli |
| Lining cells | Often attenuated/flattened respiratory epithelium | Often type II pneumocyte -like cuboidal cells | No or incomplete epithelial lining/destructed alveoli |
| Stroma | No fibrosis | Common fibrosis | Common fibrosis |
| Mesothelial invagination | No | Often | Often |
| Inflammation | None to mild | Mild to moderate | Moderate |
| Pneumothorax | Not yet | Often | Often |