Metastasis of renal cell carcinoma to the thyroid gland 19 years after nephrectomy: a case report

Although metastases to the thyroid are never uncommon at autopsy in patients who died of malignancy, metastatic thyroid carcinomas are rarely detected in clinical practice in most cases and cases of secondary thyroid cancer which require thyroid surgery clinically are few. A clinical case of thyroid metastasis from renal cell carcinoma with thyroidectomy is described herein. An 87-year-old Japanese woman was referred to us for a slow-growing palpable neck tumor with dysphagia. She had undergone a nephrectomy for renal clear cell carcinoma 19 years earlier at another hospital. Preoperative imaging examinations suspected an adenomatous goiter and a fine needle aspiration (FNA) cytology was suggestive of an atypical follicular tumor. Hemithyroidectomy was performed as a follicular tumor of thyroid for restriction of subjective symptom. A pathological examination of the thyroid tumor revealed clear cell carcinoma, postoperatively. The negative result of immunohistochemical staining for thyroglobulin also suggested metastatic renal cell carcinoma to the thyroid. Clinically significant metastases to the thyroid gland are relatively infrequent. However, if patient who bears a thyroid tumor has a history of malignancy, the possibility of metastatic disease should be taken under consideration.