Kommerell's diverticulum: an unusual cause of unilateral vocal cord palsy?

Kommerell's diverticulum is a rare congenital anomaly of the aortic arch system in which there is a left- or right-sided aortic arch with an aberrant subclavian artery on the contralateral side. Patients with this anomaly can be asymptomatic or have features of tracheal or oesophageal compression. However, there is a rising suspicion that it may be a rare cause of unilateral vocal cord palsy through its compression of the recurrent laryngeal nerve. We describe a patient who had a long history of hoarse voice and left vocal cord palsy with no other obvious cause, who was found to have a Kommerell's diverticulum on a contrast-enhanced computed tomography scan.