In patients with a hyperlucent lung, radiological differentiation between a pneumothorax and a giant bulla is not always definitive. This may result in a chest tube insertion into a pulmonary bulla with devastating results or a delay in initiating appropriate treatment for pneumothorax. Usually, distinctions between the pleural line of a pneumothorax and the bulla wall can be made by computed tomography (CT). In addition, the double wall sign of pneumothorax (parallel bulla wall and chest wall outlined by air outside the bulla) is useful in recognising the coexistence of bullae and pneumothoraces.1 Here we report a case of vanishing lung syndrome, which was diagnosed by CT in a man who presented with sudden onset of …