[Primary hypothyroidism associated with a chiasmatic syndrome simulating a prolactinoma].

Three cases of primary hypothyroidism with optic chiasm compression due to pituitary hyperplasia are reported. Patients consulted for amenorrhea, galactorrhea and visual disturbances. The study of these patients disclosed a chiasm syndrome, persistent hyperprolactinemia, decreased thyroxine and triiodothyronine associated with elevated thyrotropin stimulating hormone in blood. Computerized tomography scan revealed the presence of pituitary enlargement. Treatment with thyroid hormones resulted in total resolution of clinical features and disappearance of tomographic abnormalities.