Recurrent acute thyroid swellings because of pyriform sinus fistula

Recurrent neck infection with branchial arch fistula in children

“…The fistula then pierces the thyrohyoid membrane cranial to the superior laryngeal nerve and passes over the hypoglossal nerve. It courses behind the internal carotid artery and runs superficial to the superior laryngeal nerve, then passes through the thyroid lobe, mostly on the left side sometimes to terminate along the anterior border of the sternocleidomastoid muscle at the junction as a fistulous opening [1,5]. Fourth branchial fistulae follow a 'two-loop course', originating from the caudal end of the pyriform fossa, posterior to the fold made by the internal laryngeal nerve, and coursing inferiorly along the tracheoesophageal groove, posterior to the thyroid gland, into the mediastinum, to loop around the aorta (if on the left side) or the subclavian artery (if on the right).…”

“…Fourth branchial fistulae follow a 'two-loop course', originating from the caudal end of the pyriform fossa, posterior to the fold made by the internal laryngeal nerve, and coursing inferiorly along the tracheoesophageal groove, posterior to the thyroid gland, into the mediastinum, to loop around the aorta (if on the left side) or the subclavian artery (if on the right). The fistula then ascends cephalad to pass over the hypoglossal nerve before piercing the platysma to end on the cervical neck [1,5,6]. The theory of fifth pouch (ultimobranchial body) derivation is a relatively newly proposed one, the basis of left predominance of the fistula which may be due to the asymmetric development of the fourth branchial arch, whereby it becomes part of the aortic arch on the left side while it forms the right subclavian artery on the right.…”

Complete congenital third branchial fistula with left-sided, recurrent, suppurative thyroiditis

“…6 Third and fourth branchial arch cysts and fistulae are very rare. 4,5 The fistula then pierces the thyrohyoid membrane cranial to the superior laryngeal nerve and passes over the hypoglossal nerve. Failure of complete obliteration of the sinus results in branchial cyst formation.…”

“…1,4 They are formed during the fifth week of gestation when the second arch enlarges and grows over the second, third and fourth clefts, forming an ectodermal depression named the cervical sinus. 1, 4,5 First branchial arch anomalies are rare, occurring in only 8 per cent of cases. During embryological development, the third and fourth branchial pouches are connected to the pharynx by the pharyngobranchial duct, which degenerates by the seventh week.…”

Thyroid abscess in a 5 year old child caused by Enterococcus species: a rare case report

“…Majority of cases of AST and Thyroid abscess are seen in children with predisposing factors like pyriform sinus fistulas and thyroglossal duct anomalies. 4 The condition is associated with the persistence of a canal originating from the 3 rd or 4 th branchial pouches that may lead to recurrent thyroid abscess. 5 Pre-existing thyroid disease is also a known predisposing factor in adults, including longstanding thyroid goiter and thyroid malignancies.…”