On CT of the neck, a cystic mass located at the angle of the mandible, anterior to the sternocleidomastoid and posterior to the submandibular gland, with a 'notch sign' (tail pointing between internal and external carotid arteries) in a young adult is MOST consistent with:

• A Thyroglossal duct cyst
• B Second branchial cleft cyst ✓
• C Lymphatic malformation
• D Dermoid cyst

Explanation

Second branchial cleft cysts are the most common branchial anomalies. They appear as smooth, well-defined thin-walled cystic masses along the anterior border of the upper third of the sternocleidomastoid. The pathognomonic 'beak' or 'notch sign' on CT refers to a tail of tissue pointing medially between the internal and external carotid arteries toward the lateral pharyngeal wall. Thyroglossal cysts are midline and associated with the hyoid. Lymphatic malformations are multiloculated trans-spatial. Dermoids are fatty-containing midline structures.

Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.