Computer-tomographic appearance of branchial cleft and thyroglossal duct cysts of the neck.

The usefulness of computer tomography (CT) in the evaluation of a congenital neck mass has received little attention in the literature. We present the CT findings in two relatively common congenital neck masses - the thyroglossal duct cyst and the branchial cleft cyst. These cysts present a relatively common CT appearance of a mass with an enhancing capsule and a lucent center measuring between 20 and 35 Houndsfield Units. The branchial cleft cyst commonly occurs along the lateral border of the neck, anterior to the sternocleidomastoid muscle, while the thyroglossal duct cyst occurs along the midline of the neck. CT is excellent for determining the location, size, extent and character of these two common congenital neck masses.