Metastatic renal cell carcinoma to the thyroid gland.

OBJECTIVE To examine the presentation, diagnosis, and appropriate management of renal clear cell carcinoma metastasis to the thyroid gland. METHODS We describe a clinical case of solitary thyroid metastasis from renal clear cell carcinoma and present a comprehensive review of the related English-language literature. Common patterns of presentation and generalized overall management recommendations are evaluated and summarized. RESULTS Eight years after nephrectomy for renal carcinoma at age 61 years, a man presented with a thyroid mass. Cytology and histopathologic surgical findings were consistent with a solitary metastasis most compatible with metastatic clear cell carcinoma from his previous renal carcinoma. After left thyroid lobectomy and isthmusectomy, the patient remains disease-free 5 years later. Although uncommon, nearly 150 cases of clinically recognized metastatic renal cell carcinoma to the thyroid have been reported in the English-language literature. Metastatic disease from the kidney to the thyroid gland can occur more than 20 years after nephrectomy with the average time interval being 7.5 years. Obtaining a full clinical history in any patient who presents with a thyroid nodule is essential to allow consideration of possible metastatic disease from previous primary tumor. Metastatic disease to the thyroid gland can be correctly diagnosed preoperatively. If metastatic renal cancer is limited to the thyroid gland only, prompt, appropriate surgical intervention can be curative. CONCLUSION Metastatic renal carcinoma to the thyroid should be considered in any patient presenting with a thyroid mass and a medical history of renal cell carcinoma.