Midline cervical cysts in children. Thyroglossal anomalies.

Deep, midline cervical cysts clinically diagnosed as thyroglossal duct cysts (TDCs), have been pathologically classified as dermoid cysts because of the presence of skin appendages and a squamous epithelial lining. In 75 midline cervical masses preoperatively diagnosed as TDC, we could classify only 54 as TDC, using the preexisting criteria of squamous or ciliated columnar epithelial lining associated with a tract or thyroid follicles. Eleven cysts were reclassified as dermoid, and six were called "mixed" because of features of both dermoid cysts (skin appendages) and TDC (epithelial tract or thyroid follicles). The morphological similarity of all these lesions suggests a common origin, perhaps from totipotential tissue entrapped during the descent of the embryonic thyroglossal duct from the base of the tongue. We conclude that these lesions should be grouped together under the eponym of "thyroglossal anomalies," and that treatment for all should consist of the Sistrunk procedure.