Findings:
Correlating to the CT study a well-defined, ovoid, thick-walled, cystic lesion in the right side of the neck deep to the right sternomastoid muscle, measuring ~3.5 X 3.1 X 4.1 cm in its orthogonal dimensions. It elicits low signal intensity on the T1 sequence and mildly heterogeneous high T2/STIR signal intensity with fluid-fluid level. Moderate peripheral enhancement is noted on the postcontrast study. Additionally, a homogeneously enhancing soft tissue mass measuring 1.6 x 1.5 cm is noted overlaying the lesion superiorly, in keeping with a lymph node.
Anteriorly the lesion abuts the right submandibular gland. The carotid arteries course medially to the lesion. The cyst has a mild impression on the related structures.
Several mildly prominent bilateral submandibular lymph nodes are seen.
The soft tissue of the neck is otherwise unremarkable.
The imaged brain parenchyma is normal. The paranasal sinuses are clear.
No bony abnormality is seen.
Conclusion:
Well-defined cervical cystic mass with mild peripheral enhancement, likely in keeping with a cystic lymphangioma, DDX second branchial cleft cyst.