Thyrotropin secreting pituitary tumours: a cause of hyperthyroidism.

Pituitary thyrotropin excess resulting in hyperthyroidism has been previously reported in only 25 patients, of whom 19 had a pituitary tumour. This report describes a patient in whom a thyrotropin-producing pituitary tumour was associated with triiodothyronine thyrotoxicosis. Hypophysectomy was followed by a prompt fall in serum thyrotropin and a return to a euthyroid state.