[Hypophyseal hyperthyroidism. Non-tumoral hypersecretion of thyroid stimulating hormone with clinical...

A case of hyperthyroidism due to inappropriate TSH secretion in a 45-year-old man is presented. The diagnosis was confirmed by measurement of increased serum TSH values using three different assays, increased T4 and T3 values, the clinical picture, and the effect of anti-thyroid treatment. Nuclear magnetic resonance and computerized tomographic scans of the pituitary fossa showed no abnormalities. Treatment with long-term oral thyrotropin-releasing hormone, oral triiodothyronine, and short-term subcutaneous Sandostatin injections resulted in partial suppression of TSH without however adequate clinical effect. Treatment with thyroxin, bromocriptine, and triiodothyroacetic acid did not alter the parameters. It is concluded, that the inappropriate TSH secretion may be due to a pituitary microadenoma.