Thyrotropinoma and multinodular goiter: A diagnostic challenge for hyperthyroidism
A 63-year-old female patient was admitted to our university hospital with knee pain. The pain was present for more than ten years, but recently became intense and resistant to analgesics. She had mild hypertension, which was under control. She had exopthalmus and multiple bilateral thyroid nodules on physical examination. There was no family history of thyroid disease.\nThyroid function tests revealed high freeT3 (FT3) and freeT4 (FT4) levels with high TSH, on two consecutive tests. All other laboratory tests including thyroid auto-antibodies were normal except high follicle stimulating hormone (FSH) and luteinizing hormone (LH) levels, indicative of menopause []. The GH and age- and sex-matched IGF-1 levels were normal. The alpha subunit level was within normal range. GH suppression was obtained with the oral glucose tolerance test.\nOn ultrasonography, the right thyroid lobe measured 26 × 28 × 56 mm and the left thyroid lobe measured 29 × 30 × 61 mm. The isthmus was 15 mm and there were multiple nodules with the greatest having a diameter of 28 × 14 × 24 mm, on the right lobe. Thyroid scintigraphy revealed a minimally hyperplastic gland with hypoactive nodularity. Thyroid fine needle aspiration biopsy was consistent with benign cytology.\nThe thyrotropin-releasing hormone (TRH) test before and after the T3 suppression test was applied []. There was no response to the TRH and the results did not change after suppression with T3 preparation. An adenoma on the left side, with a 9 × 11 mm diameter, was present on pituitary magnetic resonance imaging (MRI). The tumor was hypointense in T1W Gd (+) and hyperintense in the T2W sequences. The sella basement had widened and the infundibulum was deviated to the right [ (A&B)].\nEndoscopic endonasal transsphenoidal surgery was performed and the adenoma was removed totally [ (C&D)]. Immunohistochemical examination of the tumor showed that it was a plurimorphous plurihormonal adenoma co-secreting TSH and GH [ (A&B&C&D)]. The postoperative anterior pituitary hormone levels were within normal reference range, including the thyroid hormones (TSH: 2.41 mIU/mL, FT3: 4.7 pmol/L, FT4 18.2 pmol/L).\nTwo months after pituitary surgery, the patient developed overt thyrotoxicosis with suppressed TSH levels (TSH was 0.009 uIU/mL). Thyroid scintigraphy revealed a hyperactive nodule. Radioactive iodine treatment was given. The patient was rendered euthyroid, and she is being followed without any recurrence of pituitary tumor or thyrotoxicosis.