内頸静脈内腫瘍塞栓を伴った腎細胞癌甲状腺転移例

抄録

Although renal cell carcinoma is well known for its propensity for multiple metastases, even many years after surgical treatment, metastasis to the head and neck region, including the thyroid, is rare. Herein, we report a case of metastasis in the thyroid gland and tumor in the internal jugular vein, with no increase of the serum thyroglobulin level, and also local recurrence of the carcinoma, 12 years after nephrectomy in a patient with a history of renal cell carcinoma. All the lesions appeared on the left side. Total thyroidectomy and neck dissection were performed. Histopathological examination indicated that the metastatic tumor in the thyroid was attributable to the thrombus formation and growth of the carcinoma in the veins of the thyroid gland as well as the internal jugular vein. The venous drainage from the kidney anatomically reaches the left lobe of the thyroid through the paravertebral venous plexus and internal jugular vein. Therefore, the possibility of metastasis from renal cell carcinoma to the thyroid should be considered when a thyroid tumor in the left lobe is encountered in a patient with a history of nephrectomy for renal cell carcinoma, even when the serum thyroglobulin level is in the normal range.