A branchial cleft cyst is an oval, moderately movable cystic mass that develops under the skin in the neck between the sternocleidomastoid muscle and the pharynx.
Branchial cleft cysts are remnants of embryonic development
and result from a failure of obliteration of the second branchial cleft
, which in fish
develop into gills
Most branchial cleft cysts are asymptomatic, but they may become infected
Conservative (i.e. no treatment), or surgical excision
. Recurrence is rare.