[Metastasis of kidney carcinoma to thyroid gland seventeen years after resection of primary tumor].

Renal cell carcinoma is an unpredictable tumor that can recur many years after the original diagnosis. Metastasis of this tumor to the thyroid is an uncommon occurrence that can cause clinical and pathologic problems in diagnosis. The authors report case that present clinically as a palpable thyroid nodule 17 years after the primary renal cell carcinoma had been resected. This lesion appeared a solitary "cold" nodule on iodine 131 scan and was misdiagnosed as primary thyroid neoplasm. The diagnosis was facilitated by the use of immunohistochemical study.