Branchial cleft anomalies are caused by incomplete regression of the cervical sinus of His during the sixth and seventh weeks of embryological development. First branchial cleft anomalies often appear as cysts (68%), sinuses (16%), and fistulae (16%).1 Branchial sinuses and fistulae present early in the postnatal period. Classically, they are described as draining skin pits that are found anterior to the sternocleidomastoid muscle in the superior cervical region. Males and females are equally affected.2 As many as 33% of cases are bilateral. Branchial cysts present in a bimodal age distribution, with a peak incidence at birth to age 10 years, followed by another in the second to fourth decades of life.
Imaging Quiz Case 2. Arch Otolaryngol Head Neck Surg. 2000;126(6):796-797. doi: