Renal metastasis of thyroid follicular carcinoma is a rare event, with only few cases described.[11] Moreover, metastatic thyroid tumors usually preserve a thyroid-specific immunoreaction profile for TG and TTF-1, whereas a secondary renal tumor has to be shown immunonegative for thyroid markers before being considered as a true primary. Here, TTF1 is linked to thyroid gland follicular carcinoma.