Sinus, fistula and cyst of branchial cleft

This code represents congenital anomalies arising from incomplete closure of the branchial arches during embryonic development, specifically presenting as a sinus, fistula, or cyst. These malformations are typically located in the neck, often along the anterior border of the sternocleidomastoid muscle, and may communicate with the pharynx or skin.

Use this code when documentation clearly identifies a patient with a branchial cleft sinus, fistula, or cyst. This applies to both symptomatic and asymptomatic presentations, and can be used for initial diagnosis, follow-up, or pre-operative assessment. Supporting documentation includes physician notes detailing the location, type of anomaly, and diagnostic findings.

• Differentiate from thyroglossal duct cysts (Q89.2) which are midline neck masses.
• Ensure the documentation specifies "branchial cleft" to avoid confusion with other congenital cysts or sinuses of the neck.
• Code any associated infections (e.g., L05.01 for pilonidal cyst with abscess) separately, if applicable.