SERPINA1 and pneumothorax: Vanishing lung syndrome (VLS) is also referred to as idiopathic giant bullous emphysema and is a rare manifestation of chronic obstructive pulmonary disease (COPD). Middle-aged tobacco smokers, younger marijuana users, and those with alpha-1-antitrypsin deficiency may especially be affected. The clinical and radiographic findings of VLS may initially be misinterpreted as spontaneous pneumothorax. High-resolution CT is the diagnostic imaging modality of choice in these patients and can help to differentiate VLS from pneumothorax. Such imaging also helps guide appropriate management.