Metastatic follicular thyroid carcinoma to the paranasal sinuses: a case report and review.

Thyroid carcinoma metastatic to the paranasal sinuses is extremely rare, with only 11 cases reported in the English and European literature. We report a case of metastatic follicular thyroid carcinoma to the clivus with extension into the sphenoid and posterior ethmoid sinuses. Pathological diagnosis was obtained using an intranasal endoscopic biopsy. As with our patient, metastatic thyroid carcinoma may present with symptoms related to distant metastases rather than the primary lesion. Distant metastases in differentiated thyroid carcinoma portends a poor prognosis. Our case of metastatic thyroid carcinoma to the paranasal sinuses is summarized in the context of the 11 additional cases, and treatment options are discussed.