Endocrine Abstracts

A 34-years old woman was referred to the outpatient clinic due to elevated TSH level during last three years. She was aware on the decreased thyroid function due to autoimmune thyroiditis since she was 24-years old. At that time L-thyroxine was introduced to the patient in a daily dose od 75 μg. Since elevated TSH up to 6.3 mU/l was noticed, she experienced frequent temporal headaches, noticed enlargement of hands, lips and nose, and increased shoes size. However, menstrual cycles remained regular. At the first visit, her hormone profile showed FT4 13.0 pmol/l and TSH 5.1 mU/l on the daily L-thyroxine of 150 μg. As the pituitary tumor was suspected, patient was send for contrast MR of the pituitary gland that showed an existence of macroadenoma of 17×12×11 mm in diameter. Additional analyses revealed IGF1 of 992 ng/ml, growth hormone of HR 5.0 mU/l with normal prolactin, cortisol and ACTH. No additional functional tests were performed. Echocardiography was normal while abdominal ultrasound showed slightly enlarged spleen (13×5.6 cm). The neurosurgeon has been consulted and the patient was sent for the surgical procedure. Transsfenoidal adenectomy was performed in the Departent for neurosurgery without postoperative complications. Pathohistological examination with immune-histochemical staining confirmed gowth hormone secreting pituitary adenoma. Post-surgical hormone profile showed TSH 0.88 mU/l, FT4 12.9 pmol/l, cortisol 443.8 nmol/l, IGF1 119.9 ng/ml and GH 0.14 mU/l. Patient continued with daily therapy with 100 μg of L-thyroxine, and was lost from further follow-up. In conclusion, prolonged inadequate TSH during high L-thyroxine therapy should be suspicious for TSH-secreting pituitary adenoma. This case was lacking in proper functional diagnosis before operation, adequate immune-histochemical staining on TSH and Ki-67 for the assessment of possible mixed forms and it’s aggressiveness, and proper post-surgical follow including functional testing and MR of the pituitary.