BRANCHIAL CLEFT CYSTS are congenital cysts, that arise in the lateral aspect of the neck when the second branchial cleft fails to close during embryonic development. At about the fourth week of embryonic life, 4 branchial (or pharyngeal) clefts develop between 5 ridges known as the branchial (or pharyngeal) arches. These arches and clefts contribute to the formation of various structures of the head and neck.
Branchial cleft cysts are the most common of congenital neck masses. They are bilateral in about 2-3% of the cases. Usually, they do not appear at birth, but become noticeable much later in life. If they get infected, they may form a deep neck abscess or a draining fistula. The treatment of branchial cleft cysts is surgical excision.
Occasionally, the cyst may communicate with the outside through an opening in the skin or in rare conditions, it may open into the pharynx. Note the two skin openings, on either side of the midline, above the heads of the clavicles.
Branchial Cleft Cyst
The second arch grows downwards and ultimately covers the third and fourth arches. The buried clefts normally disappear around the seventh week of development. If a portion of the cleft remains entrapped and fails to disappear, its remnants form a cyst.
Axial CT scan showing a right branchial cleft cyst.
These films of the patient shown on the left, were taken after injecting a radio-opaque dye into the skin openings (pits). They demonstrate bilateral branchial cleft tracts extending from the skin of the neck to the oropharynx.
The pits where the branchial cleft tracts open into the neck are injected with methylene blue and the sinus tracts are dissected superiorly to the oropharynx.
This branchial cleft cyst was followed superiorly to the region of the oropharynx, but no communication was found. The picture below shows the anatomy of the carotid triangle after removal of the cyst.