Educational Content: This article is for informational purposes only and does not constitute medical advice. Always consult a healthcare provider for diagnosis and treatment.
Definition of Branchial cleft cyst
Medically reviewed by Min Clinic Staff | Updated: January 2026
Branchial cleft cyst: A cavity that is a remnant from embryologic development and is still present at birth in one side of the neck, just in front of the large angulated muscle on either side (the sternocleidomastoid muscle). The cyst may not be recognized until adolescence, when it enlarges its oval shape. Sometimes a branchial cleft cyst develops a sinus or drainage pathway to the surface of the skin, from which mucus can be expressed. Total surgical excision is the treatment of choice. Also known as branchial cyst.