[Regression of a pituitary tumor, associated with primary hyperthyroidism, under the effect of 1-thyroxine].

The authors report on a successful medical treatment of a 36-year-old woman who had hypothyroidism and pituitary adenoma. Primary hypothyroidism was evidenced by decreased serum thyroxine (23 nmol/l; 1,77 micrograms/dl) and increased plasma thyroid-stimulating hormone (TSH) levels (108 mU/l). Pituitary mass with suprasellar expansion (1 cm in diameter) was proven by computed tomography (CT). The patient had been treated conventionally with 1-thyroxine and this medication was continued during a 1-year follow-up. Not only did she become symptom-free but control CT scanning revealed a large reduction of tumor size and the disappearance of suprasellar expansion.