Isolated Thyroid Metastasis From Renal Cell Carcinoma

Abstract

Metastatic thyroid carcinoma is clinically silent and found only at autopsy in most instances. The overall incidence, not surprisingly, varies from 1.25% in unselected patient autopsy series to 24% in autopsies of patients with widespread malignant neoplasms. 1-3 Although the thyroid gland is a hypervascular organ, and most metastasis to thyroid gland occurs hematogenously, metastasis to the thyroid gland is rare. In both clinical and autopsy series, renal cell, breast, and lung carcinomas are the most frequent sources of metastasis to the thyroid gland. 3,4 Renal cell carcinoma is the most common, constituting 56% of all secondary malignancies.3 Furthermore, after nephrectomy, renal cell carcinoma tends to metastasize as a solitary lesion without local tumor recurrence or distant metastasis to other organs, unlike other cancers. 5-7 We report a case of isolated thyroid metastasis from renal cell carcinoma 3 years after nephrectomy without local tumor recurrence or metastasis to other organs.