A persistent cervical sinus may present as which lesion?

A persistent cervical sinus may present as which lesion?

• A. A cervical cyst along the border of the sternocleidomastoid muscle
• B. A midline thyroglossal duct cyst
• C. A branchial fistula
• D. A cystic lesion in the floor of mouth

Answer: (A)

The main idea is that the cervical sinus forms as the second pharyngeal arch grows over the third and fourth arches and should disappear. If it fails to obliterate, it leaves a residual pocket that most commonly results in a lateral neck cyst lining up along the anterior border of the sternocleidomastoid muscle—this is the classic second branchial cleft cyst associated with a persistent cervical sinus. That lateral neck location is a hallmark, helping distinguish it from midline thyroglossal duct cysts (which sit near the hyoid in the midline), branchial fistulas (which are tracts that can connect to the skin or other structures, not simply a closed cyst), and floor-of-mouth cysts (which occur in the mouth floor rather than along the SCM).

The main idea is that the cervical sinus forms as the second pharyngeal arch grows over the third and fourth arches and should disappear. If it fails to obliterate, it leaves a residual pocket that most commonly results in a lateral neck cyst lining up along the anterior border of the sternocleidomastoid muscle—this is the classic second branchial cleft cyst associated with a persistent cervical sinus. That lateral neck location is a hallmark, helping distinguish it from midline thyroglossal duct cysts (which sit near the hyoid in the midline), branchial fistulas (which are tracts that can connect to the skin or other structures, not simply a closed cyst), and floor-of-mouth cysts (which occur in the mouth floor rather than along the SCM).