Papillary Thyroid Cancers of the Thyroid Isthmus: The Pattern of Nodal Metastasis and the Significance of Extrathyroidal Extension.

The rates of central and lateral node metastasis of isthmic PTCs are comparable with that of lobar PTCs despite a higher rate of ETE in the isthmic counterpart. Although the extent of surgery for isthmic PTCs remains to be investigated, careful dissection of perithyroidal and prelaryngeal nodes may be necessary for isthmic PTCs.