The clinical relevance of certain observations on the histology of the thyroglossal tract.

A study of all patients operated on with a clinical diagnosis of midline neck cyst at the Children's Hospital of Eastern Ontario confirms our impression that certain important facts regarding the microanatomy of thyroglossal duct cyst and its associated tract are the subject of a number of misconceptions entrenched both in surgeon's minds and in some standard reference texts. Our own observations and a review of the literature dating back to Sistrunk's own original contribution in 1920 lead us to emphasize the following: (1) thyroglossal duct cysts seldom have an intact lining; (2) the thyroglossal duct is frequently multiple and arborizes; (3) its course is always anterior to the hyoid bone; (4) it is seldom discernible to the naked eye and it is futile to attempt to dissect it out at operation. By the same token, a full Sistrunk procedure must be done even if the tract is not seen; and (5) deep cervical dermoid cysts may mimic thyroglossal duct cyst when firmly fixed to the hyoid bone, but the presence of sebaceous material in the cyst will identify it as a dermoid because thyroglossal duct cysts do not undergo keratinizing squamous metaplasia.