Forty-two patients with thyrotropin-secreting pituitary adenomas: clinical characteristics and therapeutic outcomes

D. Trukhina*^a (Ms), E. Przhiyalkovskaya^a (Dr), A. Grigoriev^a (Dr), V. Azizyan^a (Dr), A. Lapshina^a (Dr), E. Pigarova^a (Dr), E. Mamedova^a (Dr), L. Dzeranova^a (Dr), L. Rozhinskaya^a (Dr), Z. Belaya^a (Dr)

^a Endocrinology Research Centre, Moscow, RUSSIAN FEDERATION

* diadavtyan@gmail.com

Thyrotropin-secreting pituitary adenomas (TSH-PAs) are a rare entity, being the least prevalent among all PAs. Each case of TSH-PAs contributes to world practice.

Materials&methods

Single-center continuous study. TSH (0.25-3.5 mIU/L), FT4 (9-20 pmol/l), FT3 (2.5-5.5 pmol/l) measured by Architect i2000SR (Abbott Laboratories, U.S.A). MRI performed on GE Optima MR450w 1.5T. Logistic model was built using Matlab, R2021b.

Results

We enrolled 42 patients with TSH-PAs from 2010 to 2022. Median age was 46 [32;57]; men and women ratio — 1:3 (31 women). Median years before TSH-PAs diagnosis was 4, maximum — 31. The most common clinical manifestations of TSH-PAs were arrhythmias — 81.0%; neurological disorders — 57.1%; decrease in BMD — 48.8%; hypopituitarism before surgery — 4 cases.

At the initial examination, only 18 patients (42.86%) showed an increase in all TSH, FT4, FT3. Median of TSH was 4.3 [2.35;6.9], FT3 7.63 [6.2;10.72], FT4 23.46 [20.34;29.35]. SSBG, СТ-х and osteocalcin were elevated in 62.86%, 62.07% and 48.15% of cases, respectively. Cosecretion of GH-TSH was detected in 8 cases; hyperprolactinemia due to mass effect was established in 7; 1 patient had TSH-PRL PA. Most PAs were macroadenomas (31 cases); in one case no PA was detected.

Test with short-acting octreotide was performed in 24 patients and with long-acting octreotide in 12 patients: 15 and 4 patients, respectively, showed full thyroid hormone normalization. Remission was achieved in 34 patients: 28 after only neurosurgery, 3 received treatment with somatostatin analogues and 3 required somatostatin analogues after neurosurgery; 3/8 patients with no remission were lost for observation. In 23 patients, diagnosis was confirmed by IHC; all examined PAs (n=15) for SSTR2 expression were positive.

Logistic regression model of cut-off point for TSH-PAs relapse was built: early-postoperative TSH level >0.467mIU/l, SP=85,7%, SE=84,6%.

Conclusion

The diagnosis of TSH-PAs should be based on all thyroid hormones assessment, since only 42.86% of patients had all tests elevated. At the time of diagnosis 73.81% of patients had macroadenomas and 81% had cardiac arrhythmias, suggesting a long duration of disease. The most effective treatment is neurosurgery. Possible early-postoperative TSH levels model is suggested to predict relapses of TSH-PAs.

The author has declared no conflict of interest.