Metastatic papillary thyroid carcinoma to the maxilla: case report and literature review.

Metastatic tumors to the oral cavity are uncommon and a thyroid origin is considered exceedingly rare. A case of metastatic papillary thyroid carcinoma (PTC) presenting as a painful swelling in the right posterior maxilla of a 63-year-old male is reported here. The patient had been diagnosed with PTC 2 years ago and treated with thyroidectomy and radioactive iodine treatment. Radiographically, the metastatic lesion presented as a poorly-defined radiolucent lesion around an impacted maxillary third molar in the right maxilla. Histopathologic examination revealed features of PTC which was immunohistochemically positive for pancytokeratin, keratin 19 and thyroglobulin. Imaging studies revealed the presence of residual maxillary and neck disease as well as additional metastatic lesions in the sternum, ribs, and left tibia. A thorough review of the English language literature revealed only 36 previously published cases of thyroid cancer metastases to the oral cavity, the demographic and clinicopathologic features of which are summarized.