A 2019 update on TSH-secreting pituitary adenomas.

Thyrotropin-secreting pituitary adenomas (TSH-omas) present with signs and symptoms of hyperthyroidism and they are characterized by elevated serum levels of free thyroid hormones with measurable TSH levels. TSH-omas are very infrequent, accounting for less than 1% of all pituitary adenomas, thus representing a very rare cause of hyperthyroidism. For this reason, data collected on these rare disorders are relatively few, but some new researches shed new light on the etiopathogenesis, the diagnosis and the treatment of such a remarkable disease. Since the same biochemical picture is present in the syndromes of thyroid hormone resistance (RTH), in particular in the form of pituitary RTH, failure in distinguishing these clinical entities may lead to improper patient management. Conversely, early diagnosis and correct treatment of TSH-omas may prevent the occurrence of neurological and endocrinological complications, thus leading to a better rate of cure. In the present short review article, the most relevant recent advances in the pathophysiology of TSH-omas are described.

Diagnosis and treatment of TSH-secreting adenomas: review of a longtime experience in a reference center.

PURPOSE: TSH-secreting pituitary adenomas are among the less prevalent pituitary tumors, corresponding to 0.9-1.5% of all pituitary adenomas in surgical series. METHODS: A series of 11 patients with TSH-secreting and cosecreting adenomas diagnosed and treated in the last 25 years in a single center is described. RESULTS: The mean age at diagnosis was 37 years (range 18-80 years; median 23 years); the ratio of male-to-female patients was similar (6M:5F). Only three patients was the correct diagnosis established shortly after the initial medical evaluation. Other four patients were initially diagnosed with other pituitary adenomas (prolactinoma, acromegaly, and non-secreting pituitary tumor) and another four diagnosed with primary hyperthyroidism. There was a mean diagnostic delay of 6.0 years (range 0.5-25 years; median 2 years). Nine patients had macroadenomas and two patients had microadenomas. Seven patients underwent pituitary surgery which controlled the disease in only two (one micro- and one noninvasive macroadenoma). The other treatments were directed to the thyroid gland (surgery or 131I radiotherapy), pituitary radiotherapy, and somatostatin analog. CONCLUSION: In spite of its relatively straightforward diagnosis, which includes clinical/subclinical hyperthyroidism with or without goiter, increased free thyroxine and nonsuppressed TSH levels, and pituitary mass, the diagnosis of TSH-secreting and cosecreting adenomas was frequently unrecognized and thus much delayed. Serum alpha-subunit levels were high in nearly all patients with TSH-secreting adenomas and useful in excluding other conditions in the differential diagnosis. Proper indication and interpretation of simple laboratory tests should be emphasized in medical education to improve diagnostic accuracy.

Comprehensive evaluation of thyrotropinomas: single-center 20-year experience.

PURPOSE: To present a single-center 20-year experience with operated thyrotropinomas, including prevalence, clinical, biochemical and histological characteristics, and postoperative outcomes. METHODS: Retrospective series of histopathologically-proven thyrotropinomas (1993-2013), divided in two groups: A (active, central hyperthyroidism) and B (silent, no hyperthyroidism). RESULTS: Of 1628 operated pituitary adenomas, 20 were ß-TSH-positive (1.2%). In increments of 5 years, proportion of thyrotropinomas was 1, 1, 0.04 and 1.77% respectively. Median follow-up was 10.4 months (1.2-150). Group A: 6 patients (5 men), age 41 ± 12 years presented with hyperthyroidism (3), pituitary incidentaloma (2) and acromegaly (1). Tumor diameter was 2.1 ± 1.2 cm, FT4 2.68 ± 2.73 ng/dL; TSH 6.50 ± 3.68 µIU/mL. Glycoprotein alpha subunit (GSU) was uniformly elevated. Two patients had biochemical evidence of acromegaly. Tumors were plurihormonal (5 GH-positive); none atypical. Postoperative euthyroidism was achieved in 4 of 6 patients (66%). Group B: 14 patients (7 men), age 47 ± 14 years presented with acromegaly (6), mass effect (4), incidentaloma (3) and galactorrhea (1). Tumor diameter was 2.0 ± 1.0 cm. Free T4 (1.00 ± 0.24 ng/dL) and TSH (2.02 ± 1.65 mIU/L) were lower than in group A (p < 0.01). GSU was elevated in all tested cases. Nine patients had biochemical evidence of acromegaly. Tumors were plurihormonal (12 GH-positive); none atypical. Gross total resection was achieved in 12 of 14 (86%), and 1 (7%) recurred. CONCLUSION: In our series, more thyrotropinomas were operated in recent years. These tumors were often plurihormonal with heterogenous clinical presentation and frequent GH co-secretion. Surgical outcomes were good but long-term follow up is necessary.

[Thyrotropin-producing adenomas and thyrotropic hyperplasia (clinical case reports and the review of the literature)]. / Tireotropinomy i tireotrofnaia giperplaziia (opisanie klinicheskikh sluchaev i obzor literatury).

An increased blood level of the thyroid stimulating hormone (TSH) is usually associated with primary hypothyroidism (PHT) but can also be observed in such rare cases as TSH-secreting pituitary tumor. The article describes four clinical cases of elevated TSH blood levels: 1) TSH-secreting pituitary adenoma with hyperthyroidism; 2) TSH-secreting adenoma with hypothyroidism; 3) hormonally inactive pituitary adenoma combined with primary hypothyroidism; 4) reversible thyrotropic hyperplasia. These clinical situations substantiate the importance of considering different diagnoses in a patient with a pituitary gland tumor associated with an increased TSH blood level.

Increased cardiovascular morbidity and reduced life expectancy in a large Italian cohort of patients with resistance to thyroid hormone ß (RTHß).

OBJECTIVE: Decreased survival and higher cardiovascular morbidity have been recently reported in a UK cohort of 61 RTHß patients, but there is no evidence from other countries. DESIGN: Retrospective cohort study from an historical group of 284 Italian RTHß patients, diagnosed between 1984 and 2023. METHODS: We collected data on diagnosis of 284 cases and longitudinal data of 249 RTHß who carried heterozygous pathogenic variants in the THRB gene. We studied how thyroid function and recognized risk factors for cardiovascular disease, such as hypertension and diabetes, affected overall mortality and major cardiovascular events. RESULTS: The cumulative prevalence of sinus/supraventricular tachycardia and atrial fibrillation was 40% and 18%, respectively. FT4 values 57% higher than the upper limit of normal were associated with premature cardiovascular manifestations. Major cardiovascular events (MACEs) occurred in RTHß patients at a median age (IQR) of 59.4 years (50.4-66.4) and early mortality resulted in a mean of 11 years of life lost. While at univariable analysis hypertension, dyslipidemia, high fasting glucose/diabetes were also associated with MACEs, at multivariable analysis only age at diagnosis, increased fT4 levels, and male gender remained significantly associated with MACEs and age at diagnosis and higher fT4 levels with mortality. Previous thyroidectomy or radioiodine therapy had no statistically significant effect in the prevention of major cardiovascular events or all-cause mortality. CONCLUSIONS: These data should raise the general awareness on the cardiovascular risk and prompt a proactive cardiovascular monitoring in RTHß, especially in men and those with fT4 levels above 30 pmol/L.

Clinical Characteristics, Diagnosis, and Treatment of Thyroid Stimulating Hormone-Secreting Pituitary Neuroendocrine Tumor (TSH PitNET): A Single-Center Experience.

BACKGRUOUND: Thyroid-stimulating hormone (TSH)-secreting pituitary neuroendocrine tumor (TSH PitNET) is a rare subtype of PitNET. We investigated the comprehensive characteristics and outcomes of TSH PitNET cases from a single medical center. Also, we compared diagnostic methods to determine which showed superior sensitivity. METHODS: A total of 17 patients diagnosed with TSH PitNET after surgery between 2002 and 2022 in Samsung Medical Center was retrospectively reviewed. Data on comprehensive characteristics and treatment outcomes were collected. The sensitivities of diagnostic methods were compared. RESULTS: Seven were male (41%), and the median age at diagnosis was 42 years (range, 21 to 65); the median follow-up duration was 37.4 months. The most common (59%) initial presentation was hyperthyroidism-related symptoms. Hormonal co-secretion was present in four (23%) patients. Elevated serum alpha-subunit (α-SU) showed the greatest diagnostic sensitivity (91%), followed by blunted response at thyrotropin-releasing hormone (TRH) stimulation (80%) and elevated sex hormone binding globulin (63%). Fourteen (82%) patients had macroadenoma, and a specimen of one patient with heavy calcification was negative for TSH. Among 15 patients who were followed up for more than 6 months, 10 (67%) achieved hormonal and structural remission within 6 months postoperatively. A case of growth hormone (GH)/TSH/prolactin (PRL) co-secreting mixed gangliocytoma-pituitary adenoma (MGPA) was discovered. CONCLUSION: The majority of the TSH PitNET cases was macroadenoma, and 23% showed hormone co-secretion. A rare case of GH/TSH/PRL co-secreting MGPA was discovered. Serum α-SU and TRH stimulation tests showed great diagnostic sensitivity. Careful consideration is needed in diagnosing TSH PitNET. Achieving remission requires complete tumor resection. In case of nonremission, radiotherapy or medical therapy can improve the long-term remission rate.

Thyrotropinoma and multinodular goiter: A diagnostic challenge for hyperthyroidism.

Thyroid disorders are frequently encountered. The diagnosis is straightforward unless clinical or laboratory findings are inconclusive and/or perplexing. Hyperthyroidism due to a thyrotropin-secreting pituitary adenoma rarely occurs and symptoms due to thyroid hormone excess are subtle. The presentation of the disease becomes unusual when co-secretion of other hormones with thyrotropin or concomitant thyroid parenchymal pathology exist. We present the case of a 63-year-old female patient with thyrotropinoma co-secreting growth hormone and multinodular goiter. She developed hyperthyroidism first due to thyrotropinoma and later due to a toxic nodule. Herein, we discuss the diagnostic and therapeutic challenges of hyperthyroidism with atypical presentation.

A reference center study in thyrotropin-secreting pituitary adenomas: clinicopathological, therapeutic and long-term follow-up outcomes.

PURPOSE: This study aims to analyze the clinicopathological features, diagnostic steps, and therapeutic results of TSHomas and to reveal the effective factors on remission. METHODS: The clinical, radiological, and pathological features and surgical and endocrinological results of 41 TSHoma cases followed between 2005 and 2022 were retrospectively analyzed. The factors affecting the surgical cure were investigated by comparing the groups with and without remission. RESULTS: A total of 41 patients (23 male,18 female) were included in the study and the mean age was 42 (31.5-49). Palpitation and headache were the most common complaints. The time from the onset of symptoms to diagnosis was 8 (3-20) months. There were 8 patients with a preoperative clinical and biochemical diagnosis of TSH + GH co-secretion. In the TRH stimulation test, a blunted TSH response was obtained in 18 patients (90.0%). Complete suppression could not be obtained in any of the patients who underwent the T3 suppression test. The median maximum tumor diameter was 19.0 mm (6.8-41). There was microadenoma in 4 (9.8%) patients and macroadenoma in 37 patients (92.8%). Remission was achieved in 31 (75.6%) of 40 patients who underwent endoscopic transsphenoidal surgery (eTSS). The Ki-67 labeling index was 2% (1.00-4.00) in the entire patient group. Preoperative use of antithyroid drugs appears to be significantly associated with surgical cure. CONCLUSION: Diagnosis of TSHoma is still full of challenges and dynamic tests remain important. Recognition and good management of inappropriate TSH secretion states affect subsequent surgical outcomes.

Falsely elevated thyroid hormone levels associated with fibrin interference in patients receiving oral anticoagulant therapy.

OBJECTIVE: Unique clinical courses were observed in two asymptomatic patients receiving warfarin who referred to our hospital because of suspected central hyperthyroidism. We eventually diagnosed these patients with falsely elevated thyroid hormone levels caused by macroscopically invisible fibrin. Although false results caused by fibrin interference in vitro have been identified in various immunoassays, especially in blood samples from patients receiving anticoagulant therapy, no studies on thyroid function testing have been reported. The experience in evaluating these cases prompted us to investigate the independent influence of oral anticoagulants via putative fibrin interference on thyroid function testing. METHODS: We retrospectively reviewed known contributing factors that affect thyroid function testing including age, gender, medication history, body mass index, estimated glomerular filtration rate, smoking status, alcohol consumption, and the seasons of hospital visits from participants who presented the Department of Health Checkup between April 2010 and December 2020. RESULTS: A propensity-matched analysis revealed that the median serum free thyroxine levels under oral anticoagulant were significantly higher (17.9 pmol/L, n = 60) than those without anticoagulants (16.0 pmol/L, n = 60; p < 0.001). It was noted that this difference was the largest among contributing factors we analyzed. No significant differences were noted in serum thyroid-stimulating hormone levels. CONCLUSIONS: We report two patients receiving warfarin with falsely elevated thyroid hormone levels caused by fibrin interference resembling central hyperthyroidism for the first time. Our retrospective study suggests that the medication status of oral anticoagulants should be considered when evaluating thyroid function tests.

Central hyperthyroidism combined with Graves' disease: case series and review of the literature.

Background: Central hyperthyroidism is characterized by elevated free thyroid hormone and unsuppressed thyroid-stimulating hormone (TSH), and this laboratory feature includes TSH-secreting pituitary adenoma (TSHoma) and resistance to thyroid hormone ß (RTHß). Central hyperthyroidism combined with Graves' disease (GD) has been rarely reported. Case Report: We describe three patients with TSHoma combined with GD and one patient with GD combined with RTHß and pituitary adenoma. These three patients with TSHoma combined with GD showed elevated thyroid hormone, while TSH level was normal or elevated, and TSH receptor antibodies were positive. After thyrotoxicosis was controlled, they all underwent transsphenoidal surgery. We also describe a patient with an initial presentation of GD who developed hypothyroidism after anti-hyperthyroidism treatment and TSH was inappropriately significantly increased. His head magnetic resonance imaging revealed a pituitary adenoma. Genetic testing confirmed a heterozygous mutation in the thyroid hormone receptor ß gene c.1148G>A (p.R383H). After levothyroxine and desiccated thyroid tablet treatment, the TSH level decreased to normal. Conclusion: These four cases highlight the need to consider the diagnosis of GD combined with central hyperthyroidism when faced with inconsistent thyroid function test results, illuminating the specific diagnostic and therapeutic challenges of coexisting primary and central hyperthyroidism. Finally, we propose clinical management for central hyperthyroidism combined with GD.

Clinical Consequences of Variable Results in the Measurement of Free Thyroid Hormones: Unusual Presentation of a Family with a Novel Variant in the THRB Gene Causing Resistance to Thyroid Hormone Syndrome.

INTRODUCTION: Resistance to thyroid hormone ß (RTHß) is an inherited syndrome caused by dominant negative variants in the THRB gene (NM_000461.5). The clinical picture of RTHß is variable, and patients harboring the same variant may display different degrees of disease severity. CASE PRESENTATION: A 30-year-old man presented with thyrotoxicosis and central hyperthyroidism and was found to have a novel variant in the exon 10 of THRB gene (c.C1282G, p.L428V), located within the third hot spot region of the C-terminal of the receptor. Surprisingly, the same variant was found in two other relatives with an apparent normal thyroid function at initial screening. After exclusion of a TSH-secreting adenoma and serum interference in the proband, and the finding that exogenous levothyroxine failed to suppress the TSH in the brother affected by nodular goiter, relatives' thyroid function tests (TFTs) were reassessed with additional analytical method revealing biochemical features consistent with RTHß in all carriers of the p.L428V variant. Functional studies showed a slightly impaired in vitro transcriptional activity of p.L428V. Interestingly' the expression of the human p.L428V thyroid hormone receptor beta in the zebrafish embryo background generated a phenotype consistent with RTHß. CONCLUSION: Variable results of TFTs on some immunoassays can be a cause of RTHß diagnostic delay, but the genotype-phenotype correlation in this family and functional studies support p.L428V as a novel THRB variant expanding the spectrum of gene variants causing RTHß. In vivo, rather than in vitro, functional assays may be required to demonstrate the dominant negative action of THRB variants.

Hyperthyroxinemia with a non-suppressed TSH: how to confidently reach a diagnosis in this clinical conundrum.

Disorders of thyroid function are among the commonest referrals to endocrinology. While interpretation of thyroid function testing is usually straightforward, accurate interpretation becomes significantly more challenging when the parameters do not behave as would be expected in normal negative feedback. In such cases, uncertainty regarding further investigation and management arises. An important abnormal pattern encountered in clinical practice is that of high normal or raised free thyroxine (fT4) with inappropriately non-suppressed or elevated thyroid-stimulating hormone (TSH). In this short review using two clinical vignettes, we examine the diagnostic approach in such cases. A diagnostic algorithm is proposed to ensure that a definitive diagnosis is reached in these challenging cases.

Central regulation of the hypothalamo-pituitary-thyroid (HPT) axis: focus on clinical aspects.

The hypothalamus is the most prominent brain region involved in setpoint regulation of the thyroid axis. It generates the diurnal thyroid-stimulating hormone (TSH) rhythm, and it plays a central role in the adaptation of the thyroid axis to environmental factors such as caloric deprivation or infection. Many studies, including studies in human post-mortem tissue samples, have confirmed a key role for the thyrotropin-releasing hormone (TRH) neuron in the hypothalamic paraventricular nucleus (PVN) in thyroid axis regulation. In addition to their negative feedback action on TRH neurons in the hypothalamus, intrahypothalamic thyroid hormones can also modulate metabolism in adipose tissue and the liver via the autonomic nervous system. Congenital or acquired dysfunction of the hypothalamus or pituitary gland may result in central hypothyroidism (CeH). In the Netherlands, the prevalence of permanent congenital CeH as detected by neonatal screening is approximately 1 in 18000. In most neonates congenital CeH is accompanied by additional anterior pituitary hormone deficiencies, and many show clear morphological abnormalities such as a small anterior gland, a thin or absent pituitary stalk, or an ectopic posterior pituitary gland. Recently, a mutation in the immunoglobulin superfamily member 1 (IGSF1) gene was reported as a novel cause of X-linked, apparently isolated CeH occurring in neonates, children and adults. In adults, the most frequent cause of acquired CeH is a pituitary macroadenoma, usually accompanied by other pituitary hormone deficiencies. Central hyperthyroidism is a rare disorder, especially in children. In adults, it is mostly caused by a TSH-secreting pituitary adenoma.

2013 European thyroid association guidelines for the diagnosis and treatment of thyrotropin-secreting pituitary tumors.

Hyperthyroidism is mainly due to autoimmune thyroid disorders or toxic goiter, and very rarely to the presence of thyrotropin (TSH)-secreting pituitary adenomas (TSHomas). These tumors are characterized by high levels of circulating free thyroid hormones (FT4 and FT3) in the presence of nonsuppressed serum TSH concentrations. Failure to correctly diagnose TSHomas may result in inappropriate thyroid ablation, which results in a significant increase of pituitary tumor mass. The diagnosis is mainly achieved by measuring TSH after T3 suppression and TRH stimulation tests. These dynamic tests, together with pituitary imaging and genetic testing are useful in distinguishing TSHomas from the syndromes of resistance to thyroid hormone action. The treatment of choice is surgery. In cases of surgical failure, somatostatin analogs have been found to be effective in normalizing TSH secretion in more than 90% of patients.

Thyrotropin-secreting pituitary adenomas: report of 5 cases and literature review / 解放军医学杂志

Objective To study the clinical characteristic of the central hyperthyroidism due to thyrotropin-secreting pituitary adenoma. Methods 5 patients with TSH-secreting pituitary adenoma (4 male and 1 female) among 1500 pituitary adenomas were summarize between 1992 and 2006, and clinical characteristics of the 5 patients were analyzed retrospectively. Results 5 patients represented 0.33% of all pituitary adenoma patients were seen during the same period. The mean age of the patients was 39.8 years old, and mean duration 5.84 years. All patients were presented with thyrotoxicosis. 3 patients were previously considered as suffering from primary hyperthyroidism and were treated with anti-thyroid drug for 6 to 16 years, and one of them subsequently underwent hypothyroid operation twice. None of them had visual field defect. Hyperthyroidism was determined in all patients by means of elevated total or free thyroid hormone levels while serum TSH levels varied between 3.94?54.7mU/L. TRH provoked an increase in serum TSH concentration greater than 30 mU/L from the baseline level in one patient, whereas no response was observed in two patients. MRI showed pituitary macroadenomas in four patients, while microadenomas in remaining patient. Four patients underwent transsphenoidal adenomectomy and followed by radio therapy in three patients. This resulted in normalization of all hormone parameters in all patients 1-2 weeks after operation. Conclusion Central hyperthyroidism due to thyrotropin-secreting pituitary adenoma should be considered in patients with elevated thyroid hormone and non-suppressed serum TSH level. Combined treatment (transsphenoidal adenomectomy and radiotherapy) is the choice for thyrotropin-secreting pituitary adenoma.