Cysts that originate from remnants of the cervical sinus and from the clefts are, based on embryological development, called second branchial cleft cysts, (5) whereas those that arise from the pouches are called branchial pouch cysts.
2,6,8,10-12,26,28-31) Columnar respiratory epithelial tissue is seen in some cases, which might derive from branchial pouch epithelium.
20) Secondary infections of branchial pouch cysts have also been described in humans, (6,8,15) and there is 1 report of Actinomyces species as the organism cultured.
4) To definitively diagnose a third branchial pouch sinus, direct laryngoscopy is required to identify the opening of the sinus into the pharynx.
Surgical management of a case of third branchial pouch fistula.
The third branchial pouch develops into the inferior parathyroid glands and the thymus.
The superior parathyroid gland and the ultimobranchial body develop from the fourth branchial pouch, also in the vicinity of the piriform sinus.
Like other branchial pouch remnants, third pouch anomalies most frequently present as soft, nontender, well-circumscribed masses on the anterior margin of the sternocleidomastoid muscle.
The thymus is derived from the third branchial pouch
, and during embryogenesis it descends from the pharyngeal wall along the carotid sheath into the anterosuperior mediastinum.
We present 3 cases of fourth branchial pouch anomalies, describing their diagnosis, clinical course, and management, and review the literature on these anomalies.
Figure 4 represents the path that a fistula of the fourth branchial pouch and cleft would be expected to take.