A swelling at the front of the neck; forms from a duct that fails to disappear during embryonic development.
A cyst in the neck caused by persistence of portions of, or by lack of closure of, the primitive thyroglossal duct. (Dorland, 27th ed)
A thyroglossal cyst is a fibrous cyst that forms from a persistent thyroglossal duct. It usually presents as a painful midline neck lump when it becomes infected. There may be dyspepsia or dysphagia and/or difficulty breathing, especially if the lump becomes large.