Click the arrow to see the next slide with the correct interpretation.
21-Year-Old Female with Neck Mass
This case features a 21-year-old female presenting with a neck mass, ultimately diagnosed with a second branchial cleft cyst.
Imaging overview:
Axial and sagittal contrast-enhanced CT demonstrates a well-circumscribed, thin-walled cystic mass at the anteromedial border of the sternocleidomastoid muscle, posterior to the submandibular gland. The notch sign, also known as the beak sign, is present, reflecting focal extension of the cyst wall between the internal and external carotid arteries, a pathognomonic feature of second branchial cleft cyst.
Clinical insight:
Second branchial cleft cysts are the most common branchial anomaly, typically presenting as a painless lateral neck mass in a child or young adult. Their characteristic location at the anteromedial border of the sternocleidomastoid muscle, posterior to the submandibular gland, is an important imaging landmark. The notch or beak sign, representing insinuation of the cyst between the internal and external carotid arteries, is considered pathognomonic and should be specifically evaluated on cross-sectional imaging. On MRI, T1 signal is variable depending on the protein content of the cyst fluid, while T2 signal is typically high. Infected or ruptured cysts may show wall thickening and surrounding inflammation, potentially complicating diagnosis.
Case courtesy of Kelvin Tieu and Nicole Levy, MD, Temple University Hospital.