Renal metastases from well differentiated follicular thyroid carcinoma: a case report with light and electron microscopic findings.

The second case of metastatic follicular carcinoma of the thyroid presenting during life as bilateral renal masses is described. Metastases appeared 18 years after resection of the primary and on clinical evaluation were confined to the kidneys. Although most malignant tumors which present clinically in the kidney are primary there, a review of the literature indicates that the possibility of metastatic tumor must be kept in mind, particularly when the renal tumor is bilateral.