A congenital diverticulum of the brachial cleft located directly below the angle of the mandible is called?

• A. Brachial cleft cyst
• B. Branchial fistula
• C. Thyroglossal duct cyst
• D. Lateral cervical cyst

Answer: (A)

This describes a congenital neck cyst arising from remnants of the branchial apparatus. A cystic lesion in the lateral neck, just below the angle of the mandible along the anterior border of the sternocleidomastoid, is the classic location for a branchial cleft cyst. It represents a residual structure from the second branchial cleft that forms a fluid-filled sac. If a tract to the skin were present, the lesion would be a branchial fistula rather than a simple cyst. Thyroglossal duct cysts, by contrast, occur midline near the hyoid bone and typically move with swallowing or tongue protrusion. Lateral cervical cyst is a term sometimes used for similar lateral neck cysts, but the most precise designation for this description is branchial cleft cyst. On ultrasound, you’d expect a simple, anechoic or hypoechoic cyst with thin walls, though infection can make it more complex.