RESUMO
The authors report five cases of thyrotropin secreting pituitary adenomas (4 males and 1 female) in whom the diagnosis was established by a combined occurrence of elevated serum free thyroid hormone levels and measurable serum thyrotropin concentration, as well as by visualisation of the pituitary adenomas using magnetic resonance imaging (pituitary microadenoma in two and macroadenoma in three cases). Other tests were less diagnostic: only two out of 4 patients proved to be non-responders during testing with thyrotropin releasing hormone, and serum alpha subunit was elevated in only 2 out of 3 cases. There was a significant decrease of serum thyrotropin concentration in all of the four patients tested by 100 micrograms octreotide (Sandostatin, Novartis). Somatostatin-analogue treatment (slow release preparation in two cases) restored euthyroidism in all three cases treated prior to surgery. In one case the hyperthyroidism persisted after surgery of the macroadenoma, but irradiation of the pituitary area and subsequent somatostatin-analogue treatment resulted finally in a complete cure (euthyroidism and no tumor remnant). In the three other operated patients surgery resulted in euthyroidism. These cases demonstrate the variety of diagnostic and therapeutical modalities in the management of thyrotropin secreting pituitary adenomas.
