Apoplexy of pituitary macroadenoma after combined test of anterior pituitary function

Pituitary apoplexy has been reported as a very rare complication of combine d tests of anterior pituitary function and of TRH or gonadotropin-releasing hormone (GnRH) administration in pituitary tumor. A 34-year-old man with a GH-secreting pituitary macroadenoma and diabetes mellitus received an inje ction of 400 mu g TRH, 100 mu g GnRH, and 0.15 U/Kg regular insulin. Twenty minutes later, he complained of a severe headache and vomited. Visual acui ty and visual field did not change and his headache was persistent during t he next 24 hours of conservative management. Magnetic resonance imaging (MR I) of the sella turcica done the day after the event showed definitive elev ation of the optic chiasm and slight enlargement of tumor and focal areas o f mixed high signal and low signal intensities in the macroadenoma on nonco ntrast T1-weighted images. Headache subsided markedly within a day of octre otide therapy. Transsphenoidal removal of the pituitary tumor was performed 9 days after the hormone study. Ischemic necrosis and hemorrhage were conf irmed in the acidophilic adenoma with positive immunostaining for GH. Posto perative course was uneventful and his serum insulin-like growth factor-1 ( IGF-1) level and blood glucose levels were normalized. Three months after t he surgery the dynamic test was repeated without adverse effects. To our kn owledge, this is a very rare case of apoplexy of GH-secreting pituitary ade noma after a combined stimulation test of anterior pituitary function.