A branchial cleft cyst is an oval, moerately movable cystic mass that develops under the skin in the neck between the sternocleidomastoid muscle and the pharynx. It is a remnant of embryonic development and results from a failure of obliteration of the second branchial cleft. Most branchial cleft cysts are asymptomatic, but they may become infected. Treatment, when necessary, consists of surgical excision of the cyst. Recurrence is rare.