It is probable that your daughter has what is known as a 'Thyroglossal cyst' (A thyroglossal duct cyst) which is a remnant of the thyroglossal tract (duct) which is an embryologic structure concerned with the development of the thyroid gland.
A thyroglossal cyst usually presents between ages 2 - 10 years.
The majority, are found at the level of the thyrohyoid membrane, just below the hyoid bone.They are generally seeen in the midline or just off the midline, and move up and down upon swallowing and on protrusion of the tongue.
Incidence is equal in both girls and boys.These ysts are usually asymptomatic The main risk of a thyroglossal duct cyst is infection.Infected custs may drain their contents to the outside and present as an opening in the skin (sinus or a fistula).
Management is generally by surgical excision (by what is called as the sistrunk procedure). This involves excision not only of the cyst but also of the path of the thyroglossal tract.Removal of the central part of the hyoid bone is indicated to ensure complete removal of the tract.
In selected cases, before planning surgery, radioisotope scans may be needed to make sure that a 'normal' thyroid is in fact, present.
MB BS, MS, FRCS(Edinburgh)