Congenital Neck Lesions

Abstract

The thyroid gland begins to develop during the third week of pregnancy as a median outgrowth from the floor of the primitive pharynx at the level of the foramen cecum. It descends along the midline of the neck and reaches its final position by the seventh week of gestation. During this migration the thyroid is connected to the tongue by the thyroglossal duct, which normally involutes by the eighth week of fetal life. At the same time, the hyoid bone is developing from the second and third branchial arches. This simultaneous development permits the thyroglossal duct to become connected intimately with the hyoid at the anterior, posterior, or central portion. The inferior part of the thyroglossal duct becomes the pyramidal lobe of the adult thyroid gland [1]. Thyroglossal duct cyst Embryology and clinical presentation Failure of any part of the duct to involute results in cyst formation from the secreting epithelial lining of the duct. Most of the thyroglossal duct cyst (TDC) (approximately 80%) is found at the level of the hyoid bone or just below it, and few cysts are located above it. TDC accounts for approximately 70% of congenital neck masses. Approximately half of patients present before 20 years of age [2,3]. It usually manifests as a painless midline or near midline mass. Anterior cervical infection or draining sinus also might be the presenting symptom. In Telander and Deane’s report, 35% of patients had a previous history of infection [3].