| A rare malformation with characteristics of 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 abscess, acute suppurative thyroiditis, stridor, respiratory distress, odynophagia and dysphagia. Anomaly occurs as a tract from the piriform sinus to the thyroid gland. A third branchial cleft fistula passes superficial to both the superior and recurrent laryngeal nerves, which is the main difference in comparison to the fourth branchial cleft fistula. |