A literature review for 153 cases of thyrotropin-secreting pituitary adenomas in China

Abstract

Objective To explore the clinical characteristics of patients with thyrotropin-secreting pituitary adenomas (TSHomas) in China. Methods All the articles related to TSHomas were retrieved from the Chinese journal databases up to July 2017. All reported cases were assessed. Results TSHomas have been diagnosed in all ages (range: 12-81 years old, average 41.9±13.8 years old) with no gender difference (male∶female=84∶69). The rate of misdiagnosis fell from 84.6%(11/13) to 50.6%(39/77) in the last 10 years. In 92 cases (60.1%), the level of TSH was elevated [median 1.57×ULN (upper limits of normal)]. The most common elevated hormones associated with TSHomas were growth hormone (GH) and prolactin (PRL; 11.1% and 9.7%, respectively). 37 cases underwent octreotide suppression test, of which the inhibitory rates ranged from 26.2% to 94.9%(median 71.79%). The detection rate of micro-adenoma was 7.7%(1/13)before year 2000, 11.4%(4/35)from 2000 to 2006, and 26.7%(28/105) after 2006. Although TSHomas usually invade surrounding tissues, they hardly cause pituitary apoplexy. Surgery or γ-knife was performed in 132 cases (86.3%). Immunohistochemistry of tumors showed that 87(52.9%) of 46 were pure TSH adenomas and 32 (36.8%) cases were mixed ones, while GH and PRL were most common (75.0% and 56.3% respectively) in the mixed adenomas. Negative immunohistochemistry for TSH was found in 9 cases (10.3%). In the follow-up, the restoring rates of thyroid hormone and TSH level were 77.0% (87/113) and 80.0%(36/45) respectively. Conclusion TSHoma is diagnosed at an earlier age in China than that reported in Europe and America, while at similar age compared with Japan. Macro-adenomas were more common in spite of the increasing detection rate of micro-adenomas. Macro-adenomas are often invasive but less likely to induce pituitary apoplexy. Immunostaining for TSH could be negative. The most common positive immunostaining in mixed adenoma is GH and/or PRL. However, a positive immunostaining for one pituitary hormone does not necessarily correlates with its hypersecretion of that hormone. (Chin J Endocrinol Metab, 2018, 34: 660-666) Key words: Thyrotropin; Pituitary adenoma; Hyperthyroidism