The specimen consists of the epiglottis and glottis and shows anteriorly, a cyst some 3 cm. in
diameter containing brownish, gelatinous material the cyst lies immediately below the level of the
hyoid bone. The isthmus of the thyroid gland is formed by a downgrowth of a tube of epithelium
from the base of the tongue; the upper portion of this tube above the hyoid bone is lined by
squamous epithelium; if this persists and obstruction occurs, it may give rise to a "lingual dermoid".
The lower part of the duct, below the hyoid bone, is lined by columnar ciliated epithelium and
thyroglossal cysts arise from this, although more usually the duct undergoes involution.