A 19-year-old female presented with a 6-month history of progressive shortness of breath. She reported a new onset of palpitations preceding her shortness of breath, which progressed progressively into dull chest pain and trepopnea, and she experienced dyspnoea while lying on her right side. With wheezing and rhinorrhoea, the symptoms became more prominent. She had no previous history of haemoptysis, fatigue, night chills, weight loss or facial oedema. At the time of the physical examination, the heart rate was 79 beats per minute, the respiratory rate was 24 times per minute, the blood pressure was 110/72 mm Hg and the body temperature was 37.8°C. The remaining upper left lung sounds were diminished. The chest radiograph (figure 1A) revealed opacification of the left haemithorax, a displacement to the left of the heart and mediastinal structures and a hyperexpanded right lung across the midline. CT (figure 1B) and a 3D segmentation model (figure 1C–D and online supplemental video) of the thorax revealed …