A Retrospective Study Of Clinical Features And Surgical Outcomes Of Thyrotropin-secreting Pituitary Adenomas

Objective:Thyrotropin-secreting pituitary adenomas are the main cause of central hyperthyroidism.About one-third of patients were misdiagnosed as primary hyperthyroidism and underwent thyroidectomy or radioactive iodine therapy,which seriously affected the prognosis of patients.There is still no consensus on the surgical cure criteria for thyrotropin-secreting pituitary adenomas,which leads to irregular implementation of postoperative adjuvant therapy.The study aimed to provide experience for early diagnosis and efficacy evaluation by reviewing the clinical features and surgical outcomes of this disease.Methods:Through retrospective analysis of the electronic medical records of 2530 pituitary adenomas who received surgical treatment in the Neurosurgery Department of Qilu Hospital of Shandong University from January 2009 to August 2021,15 patients with thyrotropin-secreting pituitary adenomas were screened.Data collection included general information,clinical manifestations,auxiliary examinations,surgical and pathological results.Follow-up by telephone inquiries or outpatient review.The short-acting octreotide inhibition test was used to assess the sensitivity of adenomas to somatostatin analogs.Univariate analysis was performed on the relationship between gender,age,clinical symptoms,preoperative hormone levels,preoperative medication,imaging features,surgical methods,tumor texture and surgical outcomes.The receiver operating characteristic curve was constructed to find the best cut-off value of postoperative thyrotropin level indicating disease remission.P<0.05 was considered statistically significant.Results:The median age of the patients was 39 years,and male patients accounted for 67%.53%of the patients had different degrees of hyperthyroidism-related symptoms such as palpitations,hyperhidrosis or goiter.33%of the patients were previously misdiagnosed with primary hyperthyroidism and treated with antithyroid drugs.Acromegaly was present in 20%of the patients.The average tumor diameter ranged from 12 to 38 mm,and 2 had cavernous sinus invasion.Thyrotropin levels were significantly lower at 24 hours compared with 2 hours in the short-acting octreotide inhibition test(P<0.05),with inhibition rates exceeding 50%at 8-24 hours.The preoperative free tetraiodothyronine level was not significantly correlated with the preoperative thyrotropin level or tumor size(P>0.05).Eight patients(53%)achieved total tumor resection and endocrine function remission after surgery.Visual disturbance symptoms,mean tumor diameter,and suprasellar growth>1 cm were significantly associated with surgical outcomes(P<0.05).Age,sex,history of antithyroid drug use and preoperative hormone levels were not significantly associated with surgical outcomes(P>0.05).The thyrotropin level at 24 hours after surgery in the complete remission group was significantly lower than that in the incomplete remission group(P<0.05),and thyrotropin<0.2μIU/mL at 24 hours after surgery indicated complete tumor resection(P<0.05).Conclusion:(1)The postoperative cure criteria for thyrotropin-secreting pituitary should meet one of the following conditions:①thyrotropin<0.2 μIU/mL at 24 hours after surgery,regardless of whether the thyroid function returned to normal;②thyrotropin≥ 0.2μIU/mL at 24 hours after surgery,but thyrotropin and thyroid function returned to normal,and there was no residual tumor in the pituitary magnetic resonance imaging enhanced scan.(2)In the somatostatin analog inhibition test,the continuous decrease of TSH level and the inhibition rate of over 50%within 24 hours may be important for the early diagnosis of thyrotropin-secreting pituitary adenomas.