Two therapeutic approaches for thyrotropin-secreting pituitary adenomas
Marcel Sambo, Rogelio García, Elisa Fernández, Victor Andía, Diego Lezcano, Pilar Alvarez & Paloma Rodríguez
Case 1: Thirty-eight year woman consulted to gynecologist for oligomenorrhea in the last 4 years; PRL 51 μg/l and TSH 8.4 mU/l were discovered, initiating treatment with levotiroxine (f-T4). She got pregnant, persisting elevated levels of TSH and increasing f-T4, with normal campimetry. With the diagnostic of hyperthyroidism due to inadequate TSH secretion, treatment with PTU was initiated. After normal delivery, MRI showed a 22 mm. hypophisary macroadenoma and a transesphenoidal surgery was made. After this procedure, she had regular menses, but distal tremor, palpitations and tumour rests persisted with f-T4: 2.49 ng/dl, TSH:5.53 mU/l; besides IGF1: 729 μg/l, IGFBP-3: 7.93 mg/l and GH:10.8 μg/l with no response to oral glucose tolerance test. Because of these findings intramuscular Octreotide LAR treatment is introduced until 30 mg/28 days, with decrease of GH and IGF1 but thyroid hormones remained elevated. Due to this we are planning to start treatment with Pasireotide.
Case 2: Seventy-three year male with asthenia and weight loss, TSH and f-T4 levels were 15.7 mU/l and 1.08 μg/dl respectively, reason because we decided therapy with levotiroxine (from 25 to 150 μg/day) but in the follow-up he maintained elevated TSH levels and increasing f-T4 reaching 3.01 μg/dl, so L-T4 was dropped out and TRH stimulation test was made with basal TSH 26.26 and 26.7 after stimulus; MIR showed a 25 mm. hypophisary macroadenoma infiltrating both cavernous sinuses but did not compress ocular way, and positive octreoscan. Surgical treatment was refused so Octreotide LAR (20 mg/28 days) treatment was started, with normalization of hormonal parameters and with no evidence of tumour growing one year later.
Discussion: TSH-secreting pituitary tumours are rare. Often are plurisecretory and only about 40% of cases are cured with surgery due to their size and fibrous characteristics. Medical treatment with somatostatin analogues could be a good therapeutic option.