To describe the spectrum of pulmonary lesions that look likebubbles. To highlightthedistinguishing features of pulmonary cysts. To review thegamut of cystic lung diseases illustrating their thoracic and extrathoracic manifestations. To emphasize the differences in thedistribution of cysts within the lung.

Lungs can be affected by manyair-containing lesions that look like bubbles: bullae, cavities, bronquiectasis, cysts... The most important imaging modalityused inits evaluation is CT, being essential for the radiologist to know their typical features. Pulmonary cysts are uncommonlesions found in rare diseases such as Pulmonary Langerhans Cell Histyocitosis, Lymphangioleiomyomatosis and Birt-Hogg-Dubé Syndrome (multisystem disorders that usually lack of respiratory symptoms). As a result, recognizing pulmonary cysts can lead tothe diagnosis of unusualpathologies.

PULMONARY BUBBLE-LIKE LESIONS Lungs can be affected by different gas-attenuation lesions that look like bubbles including bronquiectasis, cavities, cysts, areas of honeycombing, areas of emphysema, bullae and pneumatoceles. They aredefined in The Fleischner´s Society “Glossary of Terms for Thoracic Imaging" (1) according to theirhistological and radiological features. We have focused on its appearance on CT. Bronquiectasis are permanent dilatations of the bronquial tree that look like bubbles in cross-section images. This appearance is called the “signet ring sign” (2), which consists in annular images created...

Pulmonary cysts are uncommon bubble-likelesions that may bedifficult to distinguish from otherssuch as cavities, bullae and emphysema. Recognizing pulmonary cysts can leadto the diagnosis of unusualpathologies.

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