Thyroid stimulating antibodies and metastatic thyroid carcinoma

A patient with previously treated follicular carcinoma of the thyroid developed Graves' disease with a high titre of thyroid-stimulating antibodies (TSAb). He developed functioning pulmonary metastases leading to hyperthyroidism. Levels of TSAb paralleled the functional status of the metastases suggesting that hyperfunction of the neoplastic tissues was caused by TSAb.