FIG 3. Axial view contrast-enhanced CT scans of three patients with cystic hygromas show helpful differentiating features.

A, Typical cystic hygroma shows lobulated involvement of the sublingual space (black arrow), mild heterogeneity (white arrow), and extension into the retropharyngeal space (asterisk).

B, Smooth, well-circumscribed cystic hygroma and septation (white arrow) and posterior extension into the posterior cervical space (asterisk) are present.

C, Subtle septation (arrow) is present in this well-circumscribed, homogenous cystic hygroma. Reprinted from Harnsberger (17) with permission from the Electronic Medical Education Resource Group.