Abstract
Four cases of renal adenocarcinoma with metastases to the thyroid gland are reported. In two cases the metastases developed almost simultaneously with the primary tumor, and in the other two cases there was an interval of 12 and 16 years, respectively from nephrectomy to the appearence of metastases. Some of the peculiar features of renal adenocarcinoma are briefly discussed, as well as the incidence of metastases in general to the thyroid gland, their diagnosis and principles of treatment. These four cases bring to 48 the total number of published cases of renal adenocarcinoma with metastases to the thyroid gland that we have found in the literature.