Thyroid-stimulating hormone (thyrotropin)-secretion pituitary adenoma in an 8-year-old boy: case report

Refractory hypothyroidism in children: an overview

Refractory hypothyroidism (RF) defined as raised serum levels of thyroid stimulating hormone (TSH) above upper limit of the reference range with or without the persistence of hypothyroid symptoms following a 6-week interval after the dosage was last increased to upper limits of dose per age. The most common cause of RH is inadequate compliance. In addition, diet, concomitant medication interactions, and gastrointestinal diseases can all result in l-thyroxine (LT4) malabsorption, which can cause RH. Moreover, weight gain, switching brands of LT4, poor storage of LT4, chronic liver disorders, cystic fibrosis, nephrotic syndrome, consumptive hypothyroidism, Addison's disease are significant contributors to RF in children. RH in children is frequently asymptomatic, when symptoms do occur, they are typically minor and resemble those of hypothyroidism. It is essential to identify RH early and treat its underlying cause in order to avoid overusing LT4, which can lead to cardiac and bone problems. Endocrinologists should handle children who they suspect of having RH methodically after making sure there is enough compliance. Searching for undiagnosed illnesses and/or other factors that can affect LT4 absorption could be part of this. We present this review after an extensive literature search and long-standing clinical experience. This review's objective is to shed light on the causes, clinical manifestations, investigations, and treatment of RH in children.

A Reversible Etiology of Progressive Motor Decline in a Previously Healthy Child

We describe the clinical presentation and evaluation of a 10-year-old boy who presented to our medical center with years of progressive proximal muscle weakness, muscle atrophy, and weight loss. In addition to a myopathic phenotype, he was found to have tachycardia, tremor, and learning difficulties. Electromyography revealed chronic myopathic changes and laboratory screening was notable for undetectable thyroid stimulating hormone. Follow-up testing revealed elevated thyroid peroxidase antibodies and thyroid stimulating immunoglobulins. Ultrasound examination revealed an enlarged heterogeneous thyroid gland. Four weeks after treatment with atenolol and methimazole, his strength and cognition began to improve. This case highlights the importance of evaluating for potentially reversible toxic-metabolic etiologies in children presenting with any progressive neurologic symptoms.

Consensus guideline for the diagnosis and management of pituitary adenomas in childhood and adolescence: Part 2, specific diseases

Pituitary adenomas are rare in children and young people under the age of 19 (hereafter referred to as CYP) but they pose some different diagnostic and management challenges in this age group than in adults. These rare neoplasms can disrupt maturational, visual, intellectual and developmental processes and, in CYP, they tend to have more occult presentation, aggressive behaviour and are more likely to have a genetic basis than in adults. Through standardized AGREE II methodology, literature review and Delphi consensus, a multidisciplinary expert group developed 74 pragmatic management recommendations aimed at optimizing care for CYP in the first-ever comprehensive consensus guideline to cover the care of CYP with pituitary adenoma. Part 2 of this consensus guideline details 57 recommendations for paediatric patients with prolactinomas, Cushing disease, growth hormone excess causing gigantism and acromegaly, clinically non-functioning adenomas, and the rare TSHomas. Compared with adult patients with pituitary adenomas, we highlight that, in the CYP group, there is a greater proportion of functioning tumours, including macroprolactinomas, greater likelihood of underlying genetic disease, more corticotrophinomas in boys aged under 10 years than in girls and difficulty of peri-pubertal diagnosis of growth hormone excess. Collaboration with pituitary specialists caring for adult patients, as part of commissioned and centralized multidisciplinary teams, is key for optimizing management, transition and lifelong care and facilitates the collection of health-related quality of survival outcomes of novel medical, surgical and radiotherapeutic treatments, which are currently largely missing.

Challenges in the Management of a 7-Year-Old Child with Thyrotropin-Secreting Pituitary Adenoma and the Review of the Literature

INTRODUCTION

Thyrotropin-producing pituitary adenoma (TSHoma) is a very rare disease, representing less than 1% of the pituitary tumours and presenting with elevated thyroid hormones and normal/high TSH concentrations.

CASE PRESENTATION

A 7-year-old boy with nervousness was referred by his psychiatrist for elevated free T4, T3, and TSH levels. Initial evaluation revealed an elevated α-subunit. Pituitary magnetic resonance imaging (MRI) demonstrated a macroadenoma. The patient underwent a trans-sphenoidal tumour resection (TSS) which showed positive immunohistochemical staining for TSH, growth hormone, and prolactin in tumoral tissue. Euthyroidism was achieved for 1 year after TSS, then recurrence of tumour with elevated TSH and thyroid hormone levels necessitated a re-operation with TSS followed by gamma-knife radiosurgery. The euthyroid state was achieved and lasted for 2.5 years this time, but due to the recurrence, medical treatment had been commenced with cabergoline and octreotide. Euthyroidism was maintained for the last 4 years on monthly octreotide treatment. A repeat MRI demonstrated no pituitary mass, but a mass in the sphenoidal sinus had been detected. Removal of this mass by surgery did not achieve euthyroidism. 68Ga-DOTA-TATE positron emission tomography/computed tomography showed residual tissue extending from the pituitary region to the sphenoid sinus. The patient's bone age was advanced by 2 years at diagnosis which became 4 years in 1 year after the diagnosis and remained so throughout follow-up, leading to a final height of -3.3 SDS below his target height at the age of 16 years.

CONCLUSION

The diagnosis, treatment, and follow-up of TSHomas are challenging, and short stature due to accelerated bone maturation is a complication of paediatric TSHomas.

Central Hyperthyroidism due to Thyroid-Stimulating Hormone-Secreting Pituitary Microadenoma in an Adolescent Boy: Case Report and Review of the Literature

Thyroid-stimulating hormone- (TSH-) secreting pituitary adenoma (TSH-oma) is a rare cause of secondary hyperthyroidism and can be misdiagnosed as primary hyperthyroidism. We report a case of a 15-year-old male patient who was one of two monozygotic twins and exhibited hyperthyroidism syndrome. The laboratory results showed secondary hyperthyroidism, with increased levels of free T3 (FT3) and free T4 (FT4) and no TSH inhibition. Magnetic resonance imaging (MRI) and histopathological examination of the pituitary gland confirmed pituitary microadenoma. The patient was treated with methimazole, propranolol, and somatostatin analogs to restore euthyroidism before undergoing an endoscopic transsphenoidal resection of the pituitary tumor. After surgery, the hyperthyroidism symptoms improved, thyroid hormones normalized, and MRI of the pituitary gland showed the complete removal of the tumor with no recurrence after 2 years of follow-up.

Clinical and Therapeutic Characteristics of Pituitary TSH-Secreting Adenoma in Adolescent-Onset Patients: Six Case Studies and Literature Review

BACKGROUND

Thyrotropin-secreting adenoma (TSH-oma) is a very rare kind of functional pituitary adenoma, especially that which occurs in adolescents. However, its potential clinical and therapeutic characteristics are still unknown.

OBJECTIVES

The study was aimed to summarize the clinical and therapeutic characteristics of patients with adolescent-onset TSH-oma.

METHODS

We retrospectively analyzed six (4.1%) adolescent-onset TSH-oma cases from 148 patients who were diagnosed with TSH-oma at our hospital between January 2012 and October 2020. A literature review was performed on the PubMed online database, and 14 adolescent-onset TSH-oma cases were retrieved. Then, the characteristics of clinical manifestations, treatment outcomes, and follow-ups were analyzed and compared to the adult TSH-oma patients.

RESULTS

Altogether, 20 adolescent-onset cases were included in this study having mean onset age of 13.4 ± 3.3 years. Males were found to be slightly predominant (M: F = 1.5:1) in our study. The median baseline levels of TSH, FT3, and FT4 in adolescent-onset cases were found to be 6.30 [interquartile range (IQR) 9.82] µIU/ml, 9.18 (IQR 11.61) pg/ml, and 3.22 (IQR 1.90) ng/dl, respectively, which were all significantly higher than the adult patients of our hospital. Also, the adolescent-onset cases showed more large tumor ratio (36.8% vs. 9.3%, p = 0.007) compared to the adult patients. Compared to the patients of all ages in the literature, the biochemical remission rate of SSAs (57.1%) and remission rate of TSS (38.9%) were found to be considerably lower in adolescent-onset patients, while the recurrence rate (44.4%) was found to be considerably higher.

CONCLUSIONS

Adolescent-onset TSH-oma patients showed higher TSH and thyroid hormone levels, more large tumors, and worse treatment outcomes than adult cases. Hence, early diagnosis, multidisciplinary therapy, and close follow-up should be highlighted to improve the prognosis.

Pediatric pituitary adenoma with mixed FSH and TSH immunostaining and FSH hypersecretion in a 6 year-old girl with precocious puberty: case report and multidisciplinary management

OBJECTIVE

We describe a rare case of functioning gonadotropins-producing pediatric adenoma immunostaining positively for FSH and focally for TSH causing central precocious puberty associated to central hypothyroidism in a 6 year-old girl.

MATERIALS AND METHODS

Clinical evaluation revealed precocious puberty, as confirmed by hormonal determination with elevated FSH and estradiol, while central hypothyroidism was biochemically diagnosed by a low fT4 and normal TSH. Head MRI showed the presence of a hyperintense pituitary lesion. The patient successfully underwent transsphenoidal endoscopic resection of the pituitary macroadenoma.

RESULTS

Pathologic evaluation of the tissue resected at surgery confirmed the diagnosis of pituitary adenoma with positive immunohistochemistry for FSH and focally for TSH in a mixed pattern. Ten months after surgery, there were no neurological signs and symptoms. Postoperative head MRI showed no abnormalities and no evidence of tumor regrowth.

CONCLUSIONS

Early and accurate diagnosis, multidisciplinary approach and close follow up are crucial factors for the favorable outcome.

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.

Analysis of the correlation between lipotoxicity and pituitary-thyroid axis hormone levels in men and male rats

Lipotoxicity seriously harms human health, but it is unclear whether lipotoxicity is detrimental to the pituitary. We investigated the correlation between serum triglyceride and pituitary axis hormone levels in epidemiological and animal studies. In the epidemiological study, serum thyroid-stimulating hormone (TSH), follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were greater in male patients with isolated hypertriglyceridemia than in controls, whereas adrenocorticotropin (ACTH) levels were lower in the patients with hypertriglyceridemia. Pituitary hormone levels correlated with triglyceride levels, even after adjustment for potential confounders. In the animal study, male rats were fed a high-fat or control diet for 28 weeks. As the duration of high-fat feeding increased, the serum and pituitary triglyceride concentrations increased. At early times, the high-fat diet elevated serum TSH and triiodothyronine. At later times, much higher serum TSH levels coupled with reduced thyroxine were observed in the high-fat group. Serum levels of pituitary-gonadal and pituitary-adrenal axis hormones were not affected by the diet. The mRNA and protein expression of Tshβ were greater in the high-fat group than in the control group, whereas expression of Fshβ, Lhβ and Acth had no difference between the groups. Overall, serum triglyceride levels were associated with pituitary-thyroid axis hormone levels.

[Clinical and morphological characteristics, diagnostic criteria, and outcomes of surgical treatment of TSH-secreting pituitary adenomas]

Thyrotropinomas (TSH-secreting tumors) are a rare type of pituitary adenomas, which account for about 0.5-2.0% of all pituitary tumors. The criterion of thyrotropinoma is visualization of the tumor in the presence of a normal or elevated level of the thyroid-stimulating hormone (TSH) in the blood and elevated concentrations of free T4 (fT4) and free T3 (fT3).

OBJECTIVE

To study the clinical, diagnostic, and morphological characteristics and treatment outcomes of TSH-secreting pituitary tumors.

MATERIAL AND METHODS

The study included 21 patients aged from 15 to 67 years with pituitary adenoma and a normal or elevated blood TSH level combined with elevated fT4 and fT3 levels who were operated on at the Neurosurgical Institute in the period between 2002 and 2015. Before surgery, in the early postoperative period, and 6 months after surgery, the patients were tested for levels of TSH, fT4, fT3, prolactin, cortisol, the luteinizing hormone (LH), the follicle-stimulating hormone (FSH), estradiol/testosterone, and the insulin-like growth factor (IGF-1). The thyroid status was evaluated using the following reference values: TSH, 0.4-4.0 mIU/L; fT4, 11.5-22.7 pmol/L; fT3, 3.5-6.5 pmol/L. An immunohistochemical study of material was performed with antibodies to TSH, PRL, GH, ACTH, LH, FSH, and Ki-67 (MiB-1 clone); in 13 cases, we used tests with antibodies to somatostatin receptors type 2 and 5 and to D2 subtype dopamine receptors.

RESULTS

Thyrotropinomas were detected in patients aged from 15 to 67 years (median, 39 years), with an equal rate in males (48%) and females (52%). Before admission to the Neurosurgical Institute, 11 (52%) patients were erroneously diagnosed with primary hyperthyroidism; based on the diagnosis, 7 of these patients underwent surgery on the thyroid gland and/or received thyrostatics (4 cases). Hyperthyroidism symptoms were observed in 16 (76%) patients. The blood level of TSH was 2.47-38.4 mIU/L (median, 6.56); fT4, 22.8-54.8 nmol/L (median, 36); fT3, 4.24-12.9 pmol/L (median, 9.66). Tumors had the endosellar localization in 4 (19%) cases and the endo-extrasellar localization in 17 (91%) cases. Total tumor resection was performed in 7 (33%) patients. All these tumors had the endosellar and endo-suprasellar localization. No total resection was performed in patients with infiltrative growth of adenoma (invading the skull base structures). An immunohistochemical study of tumor resection specimens detected only TSH expression in 3 (14%) cases; 18 (86%) tumors were plurihormonal and secreted TSH and GH and/or PRL. Of 13 tumors, expression of the type 2 dopamine receptor was detected in 9 (69%) cases; expression of somatostatin receptors type 5 and type 2 was found in 6 (46%) and 2 (15%) cases, respectively.

CONCLUSION

The criterion for total tumor resection was a postoperative decrease in the TSH level to 0.1 mIU/L or less. Total resection was performed in 33% of patients with tumors of only the endosellar and endo-suprasellar localization. In most cases, tumors were plurihormonal and secreted TSH and GH and/or PRL.

Thyrotropin-secreting pituitary adenomas: epidemiology, diagnosis, and management

Inappropriate secretion of TSH was first described in 1960 in a patient with evidence of hyperthyroidism and expanded sella on imaging. It was later found that a type of pituitary adenoma that secretes TSH (thyrotropinoma) was the underlying cause. The objective of the present review article is to summarize data on the epidemiology, pathogenesis, diagnosis, and management of thyrotropinomas. The prevalence of thyrotropinomas is lower than that of other pituitary adenomas. Early diagnosis is now possible thanks to the availability of magnetic resonance imaging and sensitive laboratory assays. As a corollary, many patients now present earlier in the course of their disease and have smaller tumors at the time of diagnosis. Treatment also has evolved over time. Transsphenoidal surgery is still considered definitive therapy. Meanwhile, radiation therapy, including radiosurgery, is effective in achieving tumor control in the majority of patients. In the past, radiation therapy was used as second line treatment in patients with residual or recurrent tumor after surgery. However, the availability of somatostatin analogs, which can lead to normalization of thyroid function as well as shrink these tumors, has led to an increase in the role of medical therapy in patients who are not in remission after pituitary surgery. In addition, dopamine agonists have shown some efficacy in the management of these tumors. Better understanding of the molecular pathogenesis of thyrotropinomas may lead to rationally designed therapies for patients with thyrotropinomas.

Monomorphous Plurihormonal Pituitary Adenoma of Pit-1 Lineage in a Giant Adolescent with Central Hyperthyroidism

Thyrotropin (TSH)-secreting pituitary adenomas are exceedingly rare at the pediatric age and no cases of co-secretion with other pituitary hormones in these tumors have been described in this age range. We present a case of a monomorphous plurihormonal pituitary adenoma that co-secreted TSH and GH in a pediatric patient. A 13-year-old male presented with increasing height velocity (17.75 cm/year, 9.55SD), weight loss, and visual impairment. Initial biochemical evaluations revealed secondary hyperthyroidism. A giant pituitary tumor compressing the surrounding structures was detected by magnetic resonance, and a transsphenoidal surgery was initially performed. Pathological examinations revealed an atypical, monomorphous plurihormonal Pit-1 lineage tumor with mixed features of silent subtype 3 adenoma and acidophil stem cell adenoma. In the postoperative period, secondary hyperthyroidism recurred with high levels of both GH and IGF1. In addition, due to tumor re-growth, a multimodality treatment plan was undertaken including surgery, somatostatin analogs, and radiotherapy. We report the first pediatric case of a plurihormonal TSH- and GH-secreting pituitary adenoma, further expanding the clinical manifestations of pediatric pituitary tumors. Comprehensive pathological evaluation and close follow-up surveillance are crucial to the prompt delivery of the best therapeutic options in the context of this particularly aggressive pituitary tumor.

High-Cholesterol Diet Disrupts the Levels of Hormones Derived from Anterior Pituitary Basophilic Cells

Emerging evidence shows that elevated cholesterol levels are detrimental to health. However, it is unclear whether there is an association between cholesterol and the pituitary. We investigated the effects of a high-cholesterol diet on pituitary hormones using in vivo animal studies and an epidemiological study. In the animal experiments, rats were fed a high-cholesterol or control diet for 28 weeks. In rats fed the high-cholesterol diet, serum levels of thyroid-stimulating hormone (TSH; also known as thyrotrophin), luteinising hormone (LH) and follicle-stimulating hormone (FSH) produced by the basophilic cells of the anterior pituitary were elevated in a time-dependent manner. Among these hormones, TSH was the first to undergo a significant change, whereas adrenocorticotrophic hormone (ACTH), another hormone produced by basophilic cells, was not changed significantly. As the duration of cholesterol feeding increased, cholesterol deposition increased gradually in the pituitary. Histologically, basophilic cells, and especially thyrotrophs and gonadotrophs, showed an obvious increase in cell area, as well as a potential increase in their proportion of total pituitary cells. Expression of the β-subunit of TSH, FSH and LH, which controls hormone specificity and activity, exhibited a corresponding increase. In the epidemiological study, we found a similar elevation of serum TSH, LH and FSH and a decrease in ACTH in patients with hypercholesterolaemia. Significant positive correlations existed between serum total cholesterol and TSH, FSH or LH, even after adjusting for confounding factors. Taken together, the results of the present study suggest that the high-cholesterol diet affected the levels of hormones derived from anterior pituitary basophilic cells. This phenomenon might contribute to the pituitary functional disturbances described in hypercholesterolaemia.

Asymptomatic thyrotropin-secreting pituitary macroadenoma in a 13-year-old girl: successful first-line treatment with somatostatin analogs

BACKGROUND

Thyrotropin-secreting pituitary adenomas (TSHomas) are an extremely rare cause of hyperthyroidism. Up to now there are only few cases reported in the pediatric age range. Thefirst therapeutic option is surgical resection, whereas medical treatment with somatostatin analogs has been reported only in cases wherein surgery was unsuccessful.

PATIENT FINDINGS

A 13-year-old girl was referred to our clinic for incidental finding of increased circulating free thyroid hormones in the presence of detectable TSH concentrations. She had no signs/symptoms of thyrotoxicosis. Resistance to thyroid hormone was excluded due to the lack of TSH response after thyrotropin-releasing hormone (TRH) stimulation test. Cerebral magnetic resonance imaging showed the presence of a large pituitary macroadenoma, with intra- and suprasellar extension. We decided to treat this patient with somatostatin analog as a first-line therapy because of high surgery risks due to the tumor dimensions. The response to medical treatment was excellent, with rapid and significant tumor shrinkage. No major side effects were reported. The patient developed central hypothyroidism that was corrected with L-thyroxine therapy.

SUMMARY

We report the first pediatric case of TSHoma treated with somatostatin analog as a first-line therapy. The diagnosis was challenging because of the insidious and asymptomatic presentation of the tumor.

CONCLUSIONS

We conclude that somatostatin analogs should be considered as first choice, bridge-to-surgery treatment in young patients, in order to reduce neurosurgical complications and prevent hypopituitarism during pubertal development.