METASTATIC THYROID-CANCER PRESENTING AS THYROTOXICOSIS - REPORT OF 3 CASES

Three patients with metastatic thyroid follicular carcinoma developed thyrotoxicosis. Two had mild T3 toxicosis without detectable TSH bindi ng inhibitor immunoglobulins (Tall) or thyroid stimulating antibodies (TSAb). Considerable concentration of I-131 by tumours occurred, altho ugh serum TSH was undetectable. The third patient developed thyrotoxic osis several months after treatment with I-131 had commenced and this was associated with concurrent increase in both TBII (90%; normal, les s than 11%) and TSAb (2100%). We conclude that thyrotoxicosis in patie nts with metastatic thyroid carcinoma may result from a large bulk of tumour functioning either autonomously or after stimulation by TSH rec eptor antibodies.