A cavity this is certainly a remnant from embryologic development and it is nevertheless present at birth in one side of the throat, only at the big angulated muscle mass on either side (the sternocleidomastoid muscle). The cyst might not be recognized until puberty, with regards to enlarges its oval shape. Occasionally a branchial cleft cyst develops a sinus or drainage pathway to your area of the skin, from where mucus can be expressed. Total surgical excision may be the treatment of option. Also called branchial cyst.