Table 1 Distinguishing imaging features of cystic lesions in the anterior neck

Thyroglossal duct cyst

Close association with posterior aspect of hyoid

Midline in suprahyoid neck, may be paramidline in infrahyoid neck

Branchial (second) cleft cyst

Located along anteromedial border of the sternocleidomastoid muscle, lateral to the carotid space, and at the posterior margin of the submandibular gland

Beak sign may be present (curved rim of the lesion extending between the internal and external carotid arteries)

Dermoid/epidermoid

Located in subcutaneous tissues, superficial to strap musculature, typically near suprasternal notch

Presence of fat or calcification

Laryngocele

May be primarily air-filled or with air-fluid levels due to airway communication

Involvement of laryngeal ventricle

Thymic cyst

Close association with the carotid sheath, sometimes splaying the carotid artery and jugular vein

Dumbbell or bilobed appearance can be seen with extension into the anterior mediastinum

Necrotic metastases

Multiple, growing masses

Irregular solid and cystic components

Calcifications suggestive of papillary thyroid carcinoma

Lymphatic malformation

Trans-spatial lesion

Fluid-fluid levels from recent hemorrhage