A thyroid metastasis revealing an occult renal clear-cell carcinoma

A case of renal clear-cell carcinoma presenting as a nodular thyroid metastasis is reported. The possibility of a metastatic lesion from the kidney should be taken into account in each case of clear-cell thyroid lesion. Fine needle aspiration cytology may be unable to discriminate between the renal or thyroid origin of such lesions unless PAS staining is performed.