Kommerell's diverticulum: rare cause of unilateral vocal cord palsy

Kommerell's diverticulum is a relatively rare congenital aortic arch anomaly. A 56-year-old man presented with complaint of gradually progressive hoarseness of voice since 6 months. Clinical examination revealed no evidence of palpable neck mass or cervical lymphadenopathy. Indirect laryngoscopy showed right vocal cord in median position and was immobile during phonation with normal left vocal cord. This was followed by contrast-enhanced CT (CECT) of the neck and upper chest for further evaluation. CT scan showed features of right vocal cord palsy. CECT also showed right-sided aortic arch with aberrant origin of the left subclavian artery. Aneurysmal dilatation of the aortic arch was noted at the take off of aberrant left subclavian artery suggesting Kommerell's diverticulum. Therefore, diagnosis of right vocal cord palsy due to compression of the right recurrent laryngeal nerve (RLN) by Kommerell's diverticulum was kept. Left RLN palsy did not occur in this case because the left RLN likely courses around the normal segment of the aortic arch just proximal to the origin of the left subclavian artery. As the patient was mildly symptomatic, he was kept on conservative treatment with close follow-up. The present case report highlights importance of the inclusionn of the superior mediastinum on CT scan in case of suspected vocal cord palsy to exclude vascular causes of RLN paralysis.