We present a 49 year old male patient with
thyroid stimulating hormone (TSH) producing pituitary macroadenoma. He had been mistakenly diagnosed and treated as
Graves' disease for 1 year. Serum TSH level was inappropriately elevated in the presence of high serum total and free
thyroid hormone concentrations.
Thyrotropin releasing hormone stimulation showed blunt response of TSH but good response for
prolactin. The alpha-subunit level and alpha-subunit to TSH molar ratio were measured and found to be high before surgery. The
sex hormone-binding globulin level was also high. MRI demonstrated a pituitary macroadenoma.
Insulin tolerance test and
GnRH revealed normal response. The patient was given a high dose of PTU combined with
lugol's solution for controlling
hyperthyroidism preoperatively. Transfrontal surgery was performed and the
tumor was partially removed. The diagnosis was confirmed by tissue pathology and immunohistochemistry staining of the
tumor. The immunohistochemistry staining was performed and found that
tumor cells were strongly reactive to TSH with a relatively mild degree for follicular stimulating
hormone and leutinizing
hormone. The
tumor cells were not stained for
prolactin,
growth hormone and
ACTH. Supervoltage irradiation by 60Co was delivered to the pituitary area because of persistence of
hyperthyroidism. While waiting for the remote effect of
radiotherapy, the patient was given an
antithyroid drug to control
hyperthyroidism.