ABSTRACT
Objective To study the clinical characteristic of the central hyperthyroidism due to thyrotropin-secreting pituitary adenoma. Methods 5 patients with TSH-secreting pituitary adenoma (4 male and 1 female) among 1500 pituitary adenomas were summarize between 1992 and 2006, and clinical characteristics of the 5 patients were analyzed retrospectively. Results 5 patients represented 0.33% of all pituitary adenoma patients were seen during the same period. The mean age of the patients was 39.8 years old, and mean duration 5.84 years. All patients were presented with thyrotoxicosis. 3 patients were previously considered as suffering from primary hyperthyroidism and were treated with anti-thyroid drug for 6 to 16 years, and one of them subsequently underwent hypothyroid operation twice. None of them had visual field defect. Hyperthyroidism was determined in all patients by means of elevated total or free thyroid hormone levels while serum TSH levels varied between 3.94?54.7mU/L. TRH provoked an increase in serum TSH concentration greater than 30 mU/L from the baseline level in one patient, whereas no response was observed in two patients. MRI showed pituitary macroadenomas in four patients, while microadenomas in remaining patient. Four patients underwent transsphenoidal adenomectomy and followed by radio therapy in three patients. This resulted in normalization of all hormone parameters in all patients 1-2 weeks after operation. Conclusion Central hyperthyroidism due to thyrotropin-secreting pituitary adenoma should be considered in patients with elevated thyroid hormone and non-suppressed serum TSH level. Combined treatment (transsphenoidal adenomectomy and radiotherapy) is the choice for thyrotropin-secreting pituitary adenoma.