Metastatic renal cell carcinoma of the thyroid gland: Report of a case

Abstract

A solitary metastasis of renal cell carcinoma to the thyroid gland is very rare. However, we recently experienced such a case. A-56-year-old female presented complaining of an anterior neck mass. An ultrasonogram and CT scan revealed tumors of the bilateral lobe of the thyroid gland and a concentration of ²⁰¹TI was observed in the tumors. Fine needle aspiration cytology was performed, and a benign lesion was suspected. The right lobe and isthmus of the thyroid were resected. A frozen study revealed a clear cell carcinoma and suggested it to be metastasis of renal cell carcinoma. Since no other metastasis was revealed by further examinations, a complete thyroidectomy was then performed. Metastasis from renal cell carcinoma was thereafter confirmed by both immunohistology and electron microscopy.