Two cases of 'asthma' revealing a diverticulum of Kommerell

Among embryonic aortic vascular malformations, persistence of a right aortic arch and aberrant left subclavian artery associated with a diverticulum of Kommerell is rare, and is estimated to occur in 0.1% of the general population. We report two cases of diverticulum of Kommerell in which tracheal compression due to the vascular ring induced respiratory symptoms such as asthmatic dyspnoea. This reminds us that at least a chest X-ray should be performed in newly diagnosed asthmatic patients, focusing on the trachea and upper mediastinum. In case of vascular abnormality, angiography and magnetic resonance are the best investigations to define the abnormal anatomy and guide surgery.