Clear cell renal cell carcinoma metastasizing to the thyroid gland: a case report

Metastatic tumors of the thyroid gland are rare in clinical practice. Clear cell renal cell carcinoma (ccRCC) is the most common primary site among metastatic thyroid carcinomas, accounting for 12% to 34% of all secondary thyroid tumors. Most secondary thyroid cancers have a poorer prognosis than primary papillary thyroid carcinoma. Therefore, the diagnosis and treatment of secondary thyroid tumors deserve attention. The diagnosis and treatment of secondary thyroid carcinoma pose significant challenges. We herein report a case of clear cell renal cell carcinoma metastasizing to the thyroid gland.