[Unusual anatomo-clinical features of thyroid metastasis].

The authors report a case of metastatic tumor from clear cell carcinoma in the thyroid gland occurred in a patient who had his primary tumor previously treated with right nephrectomy. The time interval before the appearance of the metastasis was 6 years. The diagnosis was made preoperatively because of the peculiar biological behavior of the primary tumor. In fact, the metastasis and the primary presented with neoplastic invasion of the middle thyroid vein and the renal vein respectively. The ultrasound examination revealed the vein thrombus arising from the thyroid and reaching the internal jugular vein through the middle thyroid vein. Subsequent fine needle aspiration biopsy confirmed the diagnosis of metastasis from clear cell renal carcinoma. The low grade of malignancy of the primary from the clinical point of view and the absence of other metastatic locations influenced the therapeutic approach.