Table 1

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
LocationLower lobes/perimediastinumLower lobes/perimediastinumUpper lobes/apex
NumberA few to multipleA few to multipleOne or a few
Basic structureAlveolar cysts/partially fused to pleuraElongated pleura/alveolus or a few alveoli within a cystIntrapleural and/or parenchymal air spaces/destructed alveoli
Lining cellsOften attenuated/flattened respiratory epitheliumOften type II pneumocyte -like cuboidal cellsNo or incomplete epithelial lining/destructed alveoli
StromaNo fibrosisCommon fibrosisCommon fibrosis
Mesothelial invaginationNoOftenOften
InflammationNone to mildMild to moderateModerate
PneumothoraxNot yetOftenOften