METASTATIC PAPILLARY THYROID-CARCINOMA PRESENTING AS A PRIMARY RENAL NEOPLASM

Clinically detectable thyroid cancer metastatic to the kidney is rare, with only six cases reported in the medical literature. Four of these have been follicular carcinoma, one papillary carcinoma, and one desc ribed as a thyroid adenoma. All of these had known thyroid neoplasms p rior to development of their renal metastases. We report herein a seve nth case of thyroid carcinoma metastatic to the kidney, unique in that the diagnosis of the kidney metastasis preceded the knowledge of the primary thyroid neoplasm. Furthermore, the follicular variant of papil lary cancer, present in this case, has not been previously described i n renal metastases from thyroid cancer. Treatment of the kidney metast ases led to the subsequent discovery and treatment of the primary thyr oid cancer. The patient underwent nephrectomy followed by total thyroi dectomy, and is alive and disease-free 3 years postoperatively. Thyroi d cancer metastatic to the kidney is rare clinically, but can be amena ble to treatment with good long term results.