Thyrotropin-secreting pituitary adenoma with growth hormone hypersecretion

A 34-year-old woman suffered from palpitation, easy sweating, heat intolerance, increased appetite, irregular menstrual cycle and hand tremor for 1 year. Thyroid function tests showed elevated serum thyroxine (T4), tri-iodothyronine (T3) and thyrotropin (TSH). Computerized tomography (CT) revealed pituitary tumor with supraseller extension. Thyrotropin releasing hormone (TRH) test showed blunted TSH response with elevated baseline level and paradoxical growth hormone (GH) response with elevated baseline level. T3 suppression test (T3 60 microg per day x 10 days) showed no inhibition of TSH (11.1 microU/mL, normal range < 6.2 microU/mL). She received transphenoidal approach and removal of tumor which measured 0.5 x 0.3 x 0.2 cm. Histopathologically, it was a pituitary adenoma which was immunoreactive for TSH, GH, follicular stimulating hormone (FSH) and luteinizing hormone (LH). To our knowledge, this case is the first case of TSH-secreting pituitary adenoma in Taiwan.