[Thyroid metastases from renal tumours: 3 cases (author's transl)].

Metastatic tumours from clear cell renal cancer were found in 3 out of 4 000 thyroidectomy specimens. These tumours appeared on scintigrams as low density nodules, one to three in number, and were accompanied in one case by signs of hyperthyroidism. They were treated by partial excision 4, 5 and 7 years after nephrectomy. One patient relapsed, was re-operated upon 2 years later and is still alive after one year. The other two patients showed no sign of relapse after 2 and 4 years respectively. When the renal history is unknown it is difficult histologically to differentiate these tumours from clear cell epitheliomas of the thyroid gland.