Thyroglossal duct remnant penetrating the hyoid bone--a case report.

Examination of the thyroglossal duct (TGD) in a senile patient with a thyroglossal duct cyst (TGDC), as well as in children, is very valuable in understanding the pathology of TGDC. The precise anatomy of TGDC was studied in a specimen obtained from a 59-year-old man using three-dimensional reconstruction. The authors found the TGD penetrated the hyoid bone. This pathological evidence has not previously appeared in the literature. Penetration of the hyoid bone by the TGD is the result of a forward growth of the hyoid bone after development of a TGD, which had appeared ventral to the hyoid bone. In this gradual forward growth, the hyoid bone had first started to press against, before eventually engulfing, the TGD.