BRANCHIAL CLEFT ANOMALIES
The 4th week of gestation is characterized by the appearance of four (later six) branchial arches separated from each other by grooves or clefts.
Internally, pharyngeal pouches correspond to the external clefts. The 2nd, 3rd and 4th of these clefts fold inward, forming a sinus which may persist as
a branchial cleft cyst. Occasionally, the 2nd cleft may fuse with the 2nd pouch to form a persistent fistula. Such a fistula originates within the
tonsillar crypt, extends into the soft tissue of the neck, passes between the internal and external carotid arteries at their bifurcation from the common
carotid artery, and exits on the side of the neck just anterior to the mid-point of the sternal head of the sternocleidomastoid muscle. The cutaneous
opening may be so inconspicuous that it remains unnoticed for years. A common parental complaint in this situation is that the collar of the child’s
shirt is always wet, but no source for the dampness can be identified. Close inspection will reveal a tiny opening in the skin, and if watched carefully,
a drop of saliva or mucus will eventually appear, confirming the diagnosis.
Both branchial cleft cysts and fistulae should be resected when found because of their potential for becoming infected. These are generally performed as
out-patient procedures with little associated morbidity.
A cartilaginous rest is associated with each branchial cleft. Small remnants of branchial cleft cartilage may persist and will be seen over the distal 1/3
of the sternal head of the sternocleidomastoid muscle. These are unsightly but are at no risk of becoming infected. They are generally resected.