Branchial cleft cyst

A branchial cleft cyst, also called a branchial cyst, is a cyst that appears as a swelling in the upper part of the neck, in front of the sternocleidomastoid muscle. It may or may not have an opening to the skin surface, and such an opening is called a fistula. The cause is usually a developmental abnormality from the early prenatal period, typically a failure of the second, third and fourth branchial clefts to close off, which involves the second branchial arches and the epicardial ridge in the lower neck. Branchial cleft cysts account for almost 20 percent of neck masses in children. Less often the cysts develop from the first, third or fourth clefts, and the position of the cyst and of any associated fistula differs accordingly.