Fourth branchial cleft anomaly

A rare otorhinolaryngeal malformation characterized by a soft, fluctuant mass, abscess or draining tract along the anterior border of the lower half of sternocleidomastoid muscle, occasionally leading to development of retropharyngeal absces, acute suppurative thyroiditis, stridor, respiratory distress, odynophagia, and dysphagia. Anomaly occurs as a tract from the piriform sinus to the thyroid gland. A fourth branchial cleft fistula passes deep to the superior laryngeal nerve but superficial to the recurrent laryngeal nerve, which is the main difference in comparison to the third branchial cleft fistula.