Functioning Metastases from Thyroid Papillary Carcinoma in Bone.

Functioning thyroid metastases are a rare cause of hyperthyroidism. Most are follicular carcinoma. Here, we report a case in which a 62-y-old man with a history of right subtotal thyroidectomy for a benign adenoma complained of symptoms of hyperthyroidism associated with left arm pain. Biopsy of a humeral lesion was consistent with papillary carcinoma metastatic from the thyroid. Postoperatively, the patient received a cumulative dose of 14.8 GBq of 131I with good control of the hyperthyroidism but without eradication of the bone metastasis.