Four cases with intra-thyroid metastases which simulate a primary tumor of the gland are reported. These metastatic lesions are probably more frequent than generally accepted. Their clinical discovery is quite frequent in patients with a renal neoplasm and is in those cases often the presenting feature of the primary tumor. Ablation of the thyroid gland is often necessary to make a correct diagnosis and to prevent local compression symptoms. This intervention is indicated whenever deemed necessary unilateral thyroid lobectomy is preferable to total ablation since it achieves its goal with a lower mortality. Postoperative radio- and chemotherapy might be added as indicated.