Investigation prior to thyroglossal duct cyst excision

Investigation of the anterior midline neck lump has been debated over the years with little agreement on best practice. Thyroglossal duct cysts (TDCs) are the most common aetiology. A TDC may contain ectopic thyroid tissue, which may affect the decision to excise.

A computerised survey was sent to a representative sample of UK-based ENT surgeons to determine current practice in investigation of presumed TDCs and the incidence of ectopic thyroid tissue.

Overall, 95% of those surveyed use ultrasonography, with 32% also arranging thyroid function tests. Fifteen per cent had encountered absent normal thyroid tissue in the presence of a midline neck swelling. In 64% of cases this represented the only functioning thyroid tissue. Thyroid function tests were normal in all but two cases.

The results show a significant change in practice over the last decade. All surgeons would arrange some form of investigation of a presumed TDC, with the vast majority using ultrasonography. Radioisotope scanning should only be used if the ultrasonography or thyroid function tests are abnormal. The incidence of ectopic thyroid tissue in this survey was higher than previously calculated, with a 0.17% prevalence of midline neck lumps representing the only functioning thyroid tissue.