[Renal metastasis of a metastasizing thyroid adenoma]

It is reported on a renal metastasis of an adenoma of the thyroid gland. The nephrectomy was performed under the suspicion of a hypernephroid carcinoma. It is referred to the difficulties of diagnostics. Is the case in question a metastasis of an otherwise benign adenoma or is primarily a highly differentiated follicular carcinoma existing? The problems on the classification of theis forms of tumours are discussed.