Hyperthyroidism caused by an ectopic TSH-secreting pituitary tumor

Central hyperthyroidism due to an ectopic TSH-secreting pituitary tumor: a case report and literature review

Ectopic thyroid-stimulating hormone (TSH)-secreting tumors are extremely rare, with only 15 reported cases in the literature. Herein, we described a 60-year-old female patient with thyrotoxicosis and elevated or unsuppressed levels of TSH. Family history and laboratory and genetic tests did not support a diagnosis of resistance to thyroid hormone (RTH). Given the unsuppressed TSH, TSH-secreting tumor was suspected, and magnetic resonance imaging (MRI) of the pituitary gland was performed. Surprisingly, the MRI scans revealed a nodule in the nasopharynx rather than a pituitary tumor in the sella region. Further evaluation using Gallium-68 DOTATATE positron emission tomography/computed tomography (68Ga-DOTATATE PET/CT) demonstrated increased DOTATATE uptake in the nasopharyngeal nodule. Additionally, an octreotide suppression test (OST) revealed an obvious reduction in TSH levels, further supporting the suspicion of the nasopharyngeal mass as the cause of inappropriate TSH secretion. To prepare for surgery, the patient received preoperative administration of octreotide, resulting in the normalization of TSH and thyroid hormone levels. The patient subsequently underwent successful surgical removal of the nasopharyngeal mass. Following the procedure, the patient experienced complete resolution of hyperthyroidism symptoms, with TSH declined and thyroid hormone levels returned to normal. Histochemistry analysis of the tumor revealed positive staining for TSH, growth hormone (GH), prolactin (PRL), luteinizing hormone (LH), and somatostatin receptor 2 (SSTR2). We discussed differential diagnosis of hyperthyroidism due to inappropriate TSH secretion, with a particular emphasis on the importance of 68Ga-DOTATATE PET/CT in combination with OST for identifying ectopic pituitary tumors.

Thyrotropin-secreting tumor "TSH-PitNET": From diagnosis to treatment

Thyrotropic adenomas (TSH-PitNET) are the rarest pituitary tumours. Most TSH-PitNETs are secreting adenoma, with a biological picture of inappropriate TSH secretion (moderately elevated TSH, elevated FT3 and FT4). Patients present most often clinical hyperthyroidism, but with more moderate symptoms than in peripheral hyperthyroidism. Biological diagnosis is not always easy. The main differential diagnoses are interfering antibody assay interactions, dysalbuminemia and thyroid hormone resistance syndrome. Misdiagnosis is common. However, the diagnosis is easier when macroadenomas are involved (80% of cases), with symptoms of optic chiasm compression, headache and signs of hypopituitarism. Treatment is initially based on surgery. In case of failure, somatostatin analogues are very effective in controlling tumor volume and secretion, although there is a risk of thyroid insufficiency, which is usually transient.

Clinical and radiological presentation of parasellar ectopic pituitary adenomas: case series and systematic review of the literature

PURPOSE

Parasellar ectopic pituitary adenomas (pEPAs) are extremely rare tumors located out of the sella turcica. PEPAs are heterogeneous entities in terms of anatomical localization and secretion of anterior pituitary hormones.

METHODS

Multicenter retrospective study. Clinical charts' consultation of patients diagnosed with parasellar lesions, to identify all subjects fulfilling the diagnostic criteria of parasellar EPAs. Systematic review of the literature focused on the medical management of prolactin-secreting pEPAs and on the prevalence of radiological bone invasion in pEPAs.

RESULTS

We identified four cases of pEPAs: (1) 54-year-old female with a prolactin-secreting suprasellar EPA successfully treated with cabergoline; (2) 74-year-old male with a non-functioning EPA of the sphenoidal sinus treated with endoscopic transsphenoidal surgery; (3) 75-year-old female with a giant lesion of the skull base (maximum diameter 7.2 cm) diagnosed as a non-functioning EPA after biopsy; (4) 49-year-old male with a silent corticotroph EPA of the sphenoidal sinus and clivus. Three out of four cases had radiological evidence of invasion of the surrounding bone structures. A systematic review of the literature highlighted that medical therapy can be effective in prolactin-secreting pEPAs. Overall, we found mention of local invasiveness in 65/147 cases (44.2%), confirmed by radiological signs of bone invasion/erosion.

CONCLUSION

Our experience confirms the heterogeneity of pEPAs in terms of clinical and radiological presentation, as well as hormone secretion. PEPAs show a high frequency of radiological bone invasion, though similar to that of sellar pituitary adenomas. Although extremely rare, pEPAs need to be considered in the differential diagnosis of parasellar lesions.

A patient with an ectopic sphenoid bone TSH secretory adenoma: Case report and review of the literature

Ectopic thyroid-stimulating hormone (TSH)oma located outside the sella turcica is exceedingly rare and can be associated with significant diagnostic delay. The clinical presentation depends on the anatomical location and size of the ectopic tumor and the degree of thyrotoxicosis. A 71-year-old woman presented with goiter and thyrotoxicosis. Initial investigations revealed elevated free thyroxine (fT4) and tri-iodothyronine (fT3) with inappropriately high-normal TSH. Assay interference was unlikely, pituitary magnetic resonance imaging (MRI) scan was reported as "normal," and germline sequencing was negative for thyroid hormone receptor ß pathogenic variants. One year later, total thyroidectomy for enlarging symptomatic goiter and suspicious nodule revealed multifocal microscopic papillary thyroid carcinoma. Six years later, she presented to an ear, nose, and throat surgeon with nasal congestion, and a sphenoid bone mass was discovered on nasoendoscopy and imaging. Ectopic TSHoma was confirmed on surgical resection, and a review of the initial pituitary MRI scan revealed the mass which had initially been missed. This is the first reported case of an ectopic TSHoma located in the sphenoid bone. Ectopic TSHoma should be considered in patients with inappropriate TSH secretion when more common differentials are excluded including thyroid hormone resistance or pituitary TSHoma.

An Update on the Pathophysiology and Diagnosis of Inappropriate Secretion of Thyroid-Stimulating Hormone

Inappropriate secretion of thyroid-stimulating hormone (IST), also known as central hyperthyroidism, is a clinical condition characterized by elevated free thyroxine and triiodothyronine concentrations concurrent with detectable thyroid-stimulating hormone (TSH) concentrations. Similarly, the term syndrome of IST (SITSH) is widely used in Japan to refer to a closely related condition; however, unlike that for IST, an elevated serum free triiodothyronine concentration is not a requisite criterion for SITSH diagnosis. IST or SITSH is an important indicator of resistance to thyroid hormone β (RTHβ) caused by germline mutations in genes encoding thyroid hormone receptor β (TRβ) and TSH-secreting pituitary adenoma. Recent evidence has accumulated for several conditions associated with IST, including RTH without mutations in the TRβ gene (non-TR-RTH), the phenomenon of hysteresis involving the hypothalamus-pituitary-thyroid axis (HPT-axis), methodological interference, and Cushing’s syndrome after surgical resection. However, little information is available on the systematic pathophysiological aspects of IST in previous review articles. This report presents an overview of the recent advances in our understanding of the etiological aspects of IST that are relevant for diagnosis and treatment. Moreover, the report focuses on the potential mechanism of IST caused by hysteresis in the HPT-axis (lagging TSH recovery) in terms of epigenetic regulation.

Case Report and Literature Review: Ectopic Thyrotropin-Secreting Pituitary Adenoma in the Suprasellar Region

Ectopic thyrotropin-secreting pituitary adenoma (ectopic TSH-oma) is a rare disorder that is easily misdiagnosed in clinical work. We report one patient who presented with hyperthyroidism and a suprasellar mass. In this case, preoperative diagnosis of suprasellar ectopic thyrotropin-secreting pituitary adenoma was challenging. A literature review revealed that a total of 11 patients with ectopic TSH-oma were previously reported, and only our one case was diagnosed in the microadenoma stage. Most of the patients with TSH-oma or ectopic TSH-oma were middle-aged. We described ectopic TSH-oma in a child at length. We recommend that ectopic TSH-oma should be considered in the differential diagnosis of thyrotoxicosis syndrome to achieve an accurate, early diagnosis. The somatostatin suppression test and imaging examinations, such as magnetic resonance imaging and positron emission tomography/magnetic resonance imaging, could contribute to the diagnosis. Once the diagnosis was highly suspected, tumor resection could achieve a satisfying long-term outcome in ectopic TSH-oma.

Ectopic pituitary adenomas: clinical features, diagnostic challenges and management

PURPOSE

Ectopic pituitary adenomas (EPAs) are extremely rare pituitary adenomas located outside the sella turcica without any connection with intrasellar components. This study aims to review all the reported cases to date and describe the clinical characteristics of EPAs.

METHODS

In a retrospective chart review, 14 patients were identified with EPAs in our hospital. A literature review was performed, and 166 cases in the literature met the criteria. Clinical data were analyzed.

RESULTS

Of 180 patients with EPAs, the mean age at diagnosis was 45.4 years, and 66.5% of the patients were females. EPAs were mainly located in the sphenoid sinus (34.4%) and suprasellar region (25.6%), followed by the clivus (15.6%), cavernous sinus (13.3%) and nasopharynx (5.6%). Adrenocorticotropic hormone (ACTH)-secreting (38.9%) and nonfunctioning (27.2%) adenomas were predominant. Patients with suprasellar EPAs were more likely to present menstrual disorders and visual changes, while patients with clival EPAs were more likely to suffer from headaches. EPAs in the cavernous sinus and suprasellar space were more likely to be initially misdiagnosed as a suspicious intrasellar mass on imaging examination. The complete tumor resection rates for EPAs in the sphenoid sinus, suprasellar region, clivus, cavernous sinus and nasopharynx were 72.3%, 88.6%, 45.0%, 73.3% and 88.9%, respectively.

CONCLUSIONS

EPA clinical characteristics varied across different tumor locations and hormone-secreting types. In addition to comprehensive hormone evaluation and careful review of imaging data, nuclear medicine and surgical biopsy should also be considered when facing differential difficulty. EPA management should be individualized.

Ectopic pituitary adenoma of the TSH-secreting sphenoidal sinus with excellent response to somatostatin analogs. Theory of the embryogenesis and literature review from a clinical case

Ectopic thyrotropin-secreting pituitary adenomas are rare, with only 10 published cases. We report the case of a 52-year-old woman who was referred for primary hypothyroidism, who showed clinical signs of hyperthyroidism and had been under treatment with levothyroxine. Her exams revealed high levels of thyroid stimulating hormone (TSH), at odds with free thyroxin (FT4) and raised triiodothyronine (T3), which remained elevated after medication suspension, suggesting possible central hyperthyroidism. Sellar MRI showed normal pituitary gland, with a mass in the sphenoid sinus of 24 mm. A possible ectopic TSH secreting pituitary tumor of sphenoid sinus was hypothesized. After a intramuscularly (IM) single dose of a sustained-relase of a somatostatin analog (octreotide) 20 mg, plasma levels of thyroid hormones were normalized and a significant tumor reduction was demonstrated in MRI control at 7-weeks' follow-up. The tumor was removed by transsphenoidal endoscopy, and the biopsy confirmed an adenoma with positive immunostaining for TSH and GH. Hyperthyroidism recurrence was observed in hormonal controls 4 weeks after surgery. Treatment with sustained-release octreotide was reinitiated, every 60-days for two years, with normalization of the thyroid hormone profile, but with a residual lesion with the appearance of a tumor in the MRI. A second tumor resection was performed, achieving sustained hormonal cure and no residual tumor lesion at 2-years' follow-up. To our knowledge, this is the first report of an ectopic thyrotropin-secreting pituitary adenoma of the sphenoid sinus. Clinical and laboratory aspects relevant to this entity are reviewed, emphasizing the usefulness of octreotide in the management of the reported case.

Secondary Hyperthyroidism due to an Ectopic Thyrotropin-Secreting Neuroendocrine Pituitary Tumor: A Case Report

INTRODUCTION

The main differential diagnoses of secondary hyperthyroidism include thyrotropin-secreting neuroendocrine pituitary tumors (TSH-PitNETs) and resistance to thyroid hormone. As a rare cause of secondary hyperthyroidism, ectopic thyrotropin-producing neuroendocrine pituitary tumors must also be considered.

CASE PRESENTATION

A 48-year-old female patient with overt hyperthyroidism and elevated thyrotropin was admitted to the endocrine outpatient clinic of a secondary care hospital in March 2018. The patient had an inconspicuous pituitary MRI and F18-F-DOPA PET-CT, but showed a tumor mass located at the pharyngeal roof. Most biochemical tests and an increased tracer uptake of the pharyngeal mass in a Ga68-DOTANOC PET-CT argued for the presence of an ectopic TSH-PitNET. After treatment with octreotide over 5 days and a consecutive normalization of free thyroxine and free triiodothyronine, the tumor was endoscopically resected. Histologically, the mass consisted of small partially spindle, partially polygonal monomorphic to mildly pleomorphic cells with immunoreactivity for thyrotropin and luteinizing hormone. Postoperatively, the patient required intermittent levothyroxine therapy.

DISCUSSION AND CONCLUSIONS

Ectopic TSH-PitNETs represent an extremely rare cause for secondary hyperthyroidism. While the diagnostic process may be complicated by negative imaging studies of the pituitary gland, family history, biochemical tests, and functional imaging using gallium-labelled somatostatin analogues may be helpful in establishing the diagnosis.

Progress in the Pathogenesis, Diagnosis, and Treatment of TSH-Secreting Pituitary Neuroendocrine Tumor

TSH-secreting pituitary neuroendocrine tumor (PitNET) is one of the causes of central hyperthyroidism. The incidence of TSH PitNET is far lower than that of other PitNETs. The clinical manifestations of TSH PitNETs mainly include thyrotoxicosis or thyroid goiter, secretion disorders of other anterior pituitary hormones, and mass effect on the pituitary gland and its surrounding tissues. The application of high-sensitivity TSH detection methods contributes to the early diagnosis and timely treatment of TSH PitNETs. Improvements in magnetic resonance imaging (MRI) have advanced the noninvasive visualization of smaller PitNETs. Treatments for TSH PitNETs include surgery, drugs, and radiotherapy. This review focuses on the progress in pathogenesis, diagnosis, and treatment of TSH PitNETs to provide more information for the clinician.

Ectopic Thyroid-Stimulating Hormone-Secreting Pituitary Adenoma of the Nasopharynx Diagnosed by Gallium 68 DOTATATE Positron Emission Tomography/Computed Tomography

BACKGROUND

Ectopic thyroid-secreting hormone (TSH)-secreting pituitary adenomas are rare, with only 9 cases reported in the literature.

CASE DESCRIPTION

We describe a case of an ectopic TSH-secreting pituitary adenoma located in the nasopharynx in a patient initially presenting with signs and symptoms of hyperthyroidism that persisted despite treatment with antithyroid medications. Magnetic resonance imaging of the pituitary gland was normal, although subsequent review by a neuroradiologist revealed a nodule attached to the posterior septum in the nasopharynx that was, in retrospect, seen on several other magnetic resonance imaging scans. Gallium 68 (⁶⁸Ga) DOTATATE positron emission tomography/computed tomography showed increased uptake in the nasopharyngeal nodule. The patient underwent resection of the nasopharyngeal mass with remission of hyperthyroidism. On pathology, the resected mass stained positive for TSH and prolactin.

CONCLUSIONS

This is the first report of use of ⁶⁸Ga-DOTATATE positron emission tomography/computed tomography to aid in localizing an ectopic TSH-secreting tumor. Prior studies have shown that ⁶⁸Ga-DOTATATE positron emission tomography/computed tomography improves detection of small lesions with shorter imaging times and lower radiation doses compared with other modalities. Our case emphasizes the importance of using ⁶⁸Ga-DOTATATE PET/CT in the diagnosis of ectopic pituitary adenomas, as these tumors can be challenging to diagnose radiographically.

Variability in Clinical Presentation and Pathologic Implications of Ectopic Pituitary Tumors: Critical Review of Literature

OBJECTIVE

Pituitary tumors are common, well-described skull base tumors of sellar origin. However, there are reports of rare ectopic pituitary tumors that are found exclusively outside of the sella turcica. Ectopic pituitary tumors have not been holistically analyzed. This study describes presentation and clinical patterns found among patients with ectopic pituitary tumors.

METHODS

A comprehensive review of the literature was performed for clinical descriptions of ectopic pituitary tumors. Reports of 85 applicable cases were evaluated.

RESULTS

The most common locations of ectopic pituitary tumors were the sphenoid sinus, clivus, suprasellar space, nasopharynx, and cavernous sinus. The majority of ectopic pituitary tumors were reported as being functional secretory tumors; they were statistically significantly more likely to be functional tumors than sellar pituitary tumors. Adrenocorticotrophic hormone, prolactin, growth hormone, and thyroid-stimulating hormone-secreting tumors were most commonly found. Bone invasion was reported in more than one third of the cases, and malignant transformations were reported in 6 cases. A large majority of patients presented with hormonal, neurologic, or physiologic symptoms.

CONCLUSIONS

Ectopic pituitary tumors are a rare entity of pituitary tumors with a presentation that can mimic those of other skull base tumors. Clinical presentation often correlates to location of the tumor. Ectopic pituitary tumors were significantly more likely to be functional secretory tumors. They may also exhibit more aggressive behavior than sellar-located tumors. Ectopic pituitary tumors may be part of a spectrum of presenting pathologies. Further genetic or genomic analysis is necessary to better understand their pathogenesis and clinical presentations.

Calcified ectopic TSH-secreting pituitary adenoma mimicking craniopharyngioma: a rare case report and literature review

Among pituitary adenomas, which are relatively common brain tumors, elements of ectopic, thyroid-stimulating hormone (TSH) secretion, and intratumoral calcification are unusual. Here, we present an extremely rare case of a calcified ectopic TSH-secreting pituitary adenoma arising from the pars tuberalis mimicking craniopharyngioma based on neuroimaging findings. To our knowledge, this is the first case report of calcified ectopic TSH-secreting pituitary adenoma without symptoms of excessive thyroid hormone secretion.

Ectopic thyrotropin secreting pituitary adenoma concomitant with papillary thyroid carcinoma: Case report

RATIONALE

Ectopic thyrotropin (TSH)-secreting pituitary adenomas are exceedingly rare. To date, there are only 6 cases reported. Here, we describe an even rarer ectopic TSH-secreting pituitary adenoma (TSH-oma) concomitant with papillary thyroid carcinoma.

PATIENT CONCERNS

A 27-year-old female was admitted to the hospital in 2002 for neck enlargement and palpitation. Thyroid function test showed increased thyroid hormones and unrepressed TSH. Thyroid ultrasound examination displayed diffuse goiter. The patient was presumptively diagnosed as primary hyperthyroidism and treated with anti-thyroid drugs. Her condition was then improved, but the serum TSH was persistently unrepressed. Therefore, central hyperthyroidism due to TSH-oma or pituitary resistance to thyroid hormone (PRTH) was suspected. Pituitary magnetic resonance imaging (MRI) examination was deservedly performed to rule out TSH-oma, which turned out to be normal. In addition, T3 suppression test was negative. Thus, PRTH, as an uncommon cause of inappropriate TSH secretion, was regarded as the working diagnosis. Triiodothyroacetic acid, which was reported to be effective for PRTH, was then administrated. But it did not work well. To control the symptoms completely and normalize the level of thyroid hormones, radioiodine therapy was carried out in 2007, followed by levothyroxine replacement therapy. Consequently, the symptoms were relieved, whereas serum TSH remained at high levels even with adequate levothyroxine. Unexpected, thyroid papillary carcinoma and a neoplasm in her nasopharynx were successively detected in 2012, which were then removed by surgery. Somewhat interestingly, the serum TSH declined to normal after the operation.

DIAGNOSES

The patient was ultimately diagnosed as an ectopic TSH-secreting pituitary adenoma concomitant with papillary thyroid carcinoma.

INTERVENTIONS

Thyroidectomy and removal of the ectopic TSH-secreting pituitary adenoma by surgery were carried out, followed by levothyroxine replacement therapy.

OUTCOME

Three years after the surgery, the patient felt well with levothyroxine 125ug daily. Serum thyroid hormones and TSH kept in normal and no signs of neoplasm recurrence.

LESSONS

Although extremely rare, ectopic TSH-secreting pituitary adenoma, as an uncommon cause of thyrotoxicosis, should be taken into consideration among those who have a longstanding hyperthyroidism with unsuppressed TSH.

DIAGNOSIS OF ENDOCRINE DISEASE: Diagnostic approach to TSH-producing pituitary adenoma

Thyrotropin (TSH)-secreting adenomas (TSHomas) are the rarest form of pituitary adenomas, and most endocrinologists will see few cases in a lifetime, if any. In most cases, the diagnostic approach is complicated and cases may be referred after being presented as a syndrome of inappropriate TSH secretion or as a pituitary mass. This review aims to cover the past, present and possible future diagnostic approaches to TSHomas, including different clinical presentations, laboratory assessment and imaging advances. The differential diagnoses will be discussed, as well as possible coexisting disorders. By evaluating the existing reports and reviews describing this rare condition, this review aims to present a clinically practical suggestion on the diagnosic workup for TSHomas, Major advances and scientific breakthroughs in the imaging area in recent years, facilitating diagnosis of TSHomas, support the belief that future progress within the imaging field will play an important role in providing methods for a more efficient diagnosis of this rare condition.

Ectopic Suprasellar Thyrotropin-Secreting Pituitary Adenoma: Case Report and Literature Review

BACKGROUND

Ectopic thyroid-stimulating hormone (TSH)-secreting pituitary adenomas are rare and can often be misdiagnosed as primary hyperthyroidism. We present a case of an ectopic suprasellar TSH-secreting pituitary adenoma. A literature review of previously reported ectopic TSH-secreting and suprasellar pituitary adenomas is included to illustrate the clinical characteristics of this disease entity and the diversity of operative approaches to treating ectopic suprasellar pituitary adenomas.

CASE DESCRIPTION

A 46-year-old man presented with typical clinical signs of hyperthyroidism and a history of progressive visual field impairment and vision loss. Laboratory investigations revealed that the patient had elevated levels of free thyroxine and free triiodothyronine and a normal level of TSH. Neuro-ophthalmologic examination showed right eye/left eye = 1.0/0.6 and left temporal hemianopia. Magnetic resonance imaging revealed a mass located in the suprasellar space. The patient underwent preoperative short-term octreotide treatment followed by gross total resection of the tumor via the extended endoscopic endonasal transtuberculum sellar approach. At 6-month follow-up evaluation, the patient's endocrinologic function tests met the criteria for cure, and magnetic resonance imaging revealed a normal pituitary gland and stalk with no tumor recurrence. Histologic diagnosis confirmed the presence of a TSH-secreting pituitary adenoma.

CONCLUSIONS

To the best of our knowledge, this is the first reported case of an ectopic suprasellar TSH-secreting pituitary adenoma. Preoperative preparation and complete resection are the keys to a cure. The extended endoscopic endonasal transtuberculum sellar approach is an alternative minimally invasive method for the removal of an ectopic suprasellar pituitary adenoma.

Evaluation and management of thyrotropin-secreting pituitary adenomas

Thyrotropin (TSH)-secreting pituitary adenomas are uncommon pituitary neoplasms. They have been increasingly recognized with the advent of ultrasensitive TSH assays and advanced pituitary imaging. Clinically, patients may often present with signs and symptoms of hyperthyroidism. Some patients may present with tumor-related local mass effect, anterior hypopituitarism or syndromes related to co-secretion of other pituitary hormones. Their diagnosis and differential diagnosis from other causes of hyperthyroidism and ‘inappropriate TSH secretion’ often presents a clinical challenge. While trans-sphenoidal pituitary adenomectomy remains the therapeutic modality of choice, medical treatment with somatostatin receptor agonists or dopamine agonists is often needed as adjunctive therapy or perhaps as a potential alternative to surgery. Radiation therapy to the sella may be advised as a third-line therapy.

Nasally located ectopic ACTH-secreting pituitary adenoma (EAPA) causing Nelson's syndrome: diagnostic challenges

PURPOSE

We report the first case of an Ectopic adrenocorticotrophin (ACTH)-secreting pituitary adenoma (EAPA) located within the posterior nasal septum associated with Nelson's syndrome, which eluded diagnosis for over a decade. In this report, we explore the reasons for such diagnostic difficulty and suggest ways in which an earlier diagnosis may be made.

METHODS AND RESULTS

A 19 years old Lebanese man presented in 2000, with overt Cushing's syndrome confirmed with markedly elevated urine free cortisols and failed dexamethasone suppression tests. An unsuppressed ACTH and a possible 5 mm adenoma on MRI (Magnetic Resonance Imaging) pituitary suggested Cushing's disease. The patient underwent trans-sphenoidal surgery (TSS), but histology revealed normal pituitary tissue and Cushing's syndrome persisted. A repeat MRI pituitary showed no anomaly, and extensive investigations failed to locate an ectopic lesion. Subsequently a bilateral adrenalectomy was performed. Over the ensuing years, the patient developed Nelson's syndrome with hyperpigmentation and markedly elevated ACTH levels. Repeated high dose dexamethasone suppression tests, corticotrophin releasing hormone (CRH) tests, and CRH stimulated inferior petrosal sinus samplings (IPSS) suggested a pituitary origin of the ACTH. Two further TSS were unsuccessful. The pituitary was irradiated. Subsequent review of his previous MRIs revealed an enlarging mass within the posterior nasal septum, which was excised in 2011. The histology confirmed the diagnosis of an EAPA within the nasal septum.

CONCLUSION

Ectopic ACTH-secreting pituitary adenomas can occur not only along the developmental route of Rathke's pouch, but other aberrant locations giving a clinical and biochemical picture identical to Cushing's disease or Nelson's syndrome. Clinicians should suspect an EAPA, when a central ACTH source seems to be apparent with no obvious pituitary adenoma. A detailed MRI involving possible EAPA sites aids in locating these unusual lesions.

Thyroid-stimulating hormone-secreting ectopic pituitary adenoma of the nasopharynx

Thyroid-stimulating hormone-secreting ectopic pituitary adenoma of the nasopharynx is highly unusual, with only three reported cases in the world literature. We describe the clinical presentation and radiologic findings in one patient with such rare lesions. A 46-year-old male with typical symptoms of Grave's disease was found to have a mass on magnetic resonance imaging. An otolaryngologic examination revealed a nasopharyngeal mass lesion, which was endoscopically resected. The results of immunohistochemical staining for thyroid-stimulating hormone were positive. After the resection, the patient's TSH was within normal limits. The clinical significance of the case and a brief literature review are presented.

Current role and value of fine-needle aspiration in nodular goitre

Thyroid nodules are common and, depending on the detection technique used, can affect 50% or greater of the population. The primary diagnostic test to assess the nature of these nodules is fine-needle aspiration cytology. Most thyroid nodules are benign and often are multiple. However, the morphology of these nodules may mimic neoplasms showing features such as papillary growth, micro-follicles and even oncocytic metaplasia. Lesions with these features may be considered indeterminate for neoplasm or malignancy, and often require surgical excision to define their nature. The role of cytopathology in this area is to screen those definitely benign nodules, thus preventing surgery and reassuring both the patient and the clinician. In this review, we demonstrate many of the morphological manifestations of nodular goiter and stress the necessity of careful preparatory techniques. Although the past several years have witnessed the development of molecular testing to refine diagnostic cytology in the thyroid, it is still the role of the cytopathologist to identify those "indeterminant" nodules which should be tested. Thus, the cytopathologist contributes both an essential diagnostic and an important cost saving role which hopefully will continue in the future.

Ectopic TSH-secreting pituitary tumor: a case report and review of prior cases

Background

Ectopic TSH-secreting pituitary adenoma (TSH-oma) is a very unusual disorder. To date, there are only four cases reported. It is difficult to distinguish ectopic cases from both regular TSH-omas and resistance to thyroid hormone (RTH).

Case presentation

A newly identified case of ectopic TSH-oma arising from the nasal pharynx was described, and reports of four prior cases were reviewed. The patient was a 41-year-old male who developed what appeared to be typical hyperthyroidism and atrial fibrillation in 2009. Thyroid function tests showed elevated basal levels of free T₃ (FT₃, 24.08 pmol/L), free T₄ (FT₄, 75.73 pmol/L), and serum TSH (7.26 μIU/ml). Both TSH-oma and resistance to thyroid hormone syndrome were considered. TRH stimulating test was negative, whereas octreotide inhibition test showed a reduction in TSH by 30.8%. Furthermore, a large space-occupying lesion located at the nasopharynx was found by computed tomography and magnetic resonance imaging (MRI). A normal pituitary was visualized. Ectopic TSH-oma was preliminarily established. Using an endoscopic endonasal approach, the tumor was resected. Histological features and immunophenotypes were consistent with those of TSH-secreting tumor. The levels of both free thyroxine and TSH returned to normal ranges the day after surgery and remained within normal range for 48 months.

Conclusions

Although exceedingly rare, ectopic TSH-oma should be considered for patients with inappropriate secretion of TSH with hyperthyroidism and pituitary tumor undetectable by computed tomography and MRI. To our knowledge, this is the first case followed up more than 4 years. The characteristics and successful interventions summarized in this report provide a guideline for clinicians.

Hyperthyroidism caused by an ectopic thyrotropin-secreting tumor of the nasopharynx: a case report and review of the literature

BACKGROUND

Ectopic thyrotropin (TSH)-secreting tumors are extremely rare. To our knowledge, only three cases have previously been reported so far, but the tumors were not studied ultrastructurally and in vitro. We present a case that was extensively examined to gain deeper insights in terms of the histopathological features and hormonal secretion profile of the tumor.

PATIENT FINDINGS

A 49-year-old female complained of nasal obstruction for 15 years and thyrotoxicosis for one and a half years. Except for a high basal TSH with concomitantly elevated free tri-iodothyronine (FT3) and free thyroxine (FT4) levels, her pituitary hormone profile yielded normal results. Magnetic resonance imaging revealed a 2 cm × 2 cm mass in the nasopharynx, which showed an increased tracer uptake on octreotide scintigraphy. Preoperative treatment with octreotide effectively reduced serum TSH, FT3, and FT4 to normal levels. The mass was endoscopically removed via an endonasal approach. Immunophenotyping and hormone determination of cultured cells confirmed that the mass was a plurihormonal TSH-/growth hormone (GH)-/prolactin (PRL)-producing adenoma. Co-expression of TSH and GH was found in most cells. Electron microscopy showed that the adenoma was formed by a single cell type, with secretory granules of small size. In vitro studies demonstrated that octreotide reduced both TSH and GH secretion.

SUMMARY

We report an ectopic TSH-secreting tumor, which had plurihormonal secretion in vitro, including TSH, GH, and PRL. Histologically, it mimicked a TSH-secreting pituitary adenoma. Octreotide was useful in the diagnosis and treatment of this ectopic TSH-secreting tumor.

CONCLUSIONS

Ectopic TSH-secreting tumors are extremely rare. In terms of hormone secretion profile, histological characteristics, and response to octreotide, they are similar to pituitary TSH-secreting adenomas, suggesting that they are of identical cell origin.

Thyrotropin-secreting adenoma in a patient with primary hypothyroidism

OBJECTIVE

To describe a patient who developed a thyrotropin (TSH)-secreting adenoma in the setting of primary hypothyroidism.

METHODS

We report the clinical, laboratory, and radiologic findings of a patient with a history of primary hypothyroidism who presented with headache, a bitemporal visual field deficit, and elevated TSH despite long-term levothyroxine therapy. We discuss the diagnostic challenges of this case and review the relevant literature.

RESULTS

A 54 year old woman with a history of primary hypothyroidism presented with a 3-year history of headache and a week of worsening vision. Imaging revealed a heterogeneous sellar mass elevating the optic chiasm. Her serum TSH was 46.5 mIU/L and free thyroxine concentration was 0.1 ng/dL. The differential diagnosis included pituitary hyperplasia and a TSH-secreting adenoma in a patient with primary hypothyroidism. The pathologic characteristics of the tumor were consistent with the latter.

CONCLUSION

In a patient with an elevated TSH concentration and a previous diagnosis of hypothyroidism, it is important to consider other entities besides medication noncompliance. TSH-secreting adenomas can also cause elevated levels of TSH.

[TSH-secreting pituitary tumors: two case reports and literature review]

INTRODUCTION

TSH-secreting pituitary adenomas are rare pituitary functioning tumors accounting for less than 2% of the pituitary adenomas. The clinical feature consists of thyrotoxicosis occasionally associated to tumoral symptoms due to mass effect. The biochemical feature consists of elevated thyroid hormones levels and normal or high TSH concentrations. This disease is often wrongly diagnosed as Grave's disease, and the ablative therapy is frequently conducted prior to the diagnosis.

OBJECTIVE

To report two cases followed in the Neuroendocrine Unit of Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo and to review the literature aiming at the management of this affection.

CONCLUSION

In the presence of elevated thyroid hormone levels associated with inappropriate normal or increased TSH levels, the possibility of a TSH-secreting pituitary adenoma should be considered for the proper medical treatment.

Pituitary tumours: TSH-secreting adenomas

Thyrotropin-secreting pituitary adenomas (TSHomas) are a rare cause of hyperthyroidism and account for less than 2% of all pituitary adenomas. In the last years, the diagnosis has been facilitated by the routine use of ultra-sensitive TSH immunometric assays. Failure to recognise the presence of a TSHoma may result in dramatic consequences, such as improper thyroid ablation that may cause the pituitary tumour volume to further expand. The diagnosis mainly rests on dynamic testing, such as T3 suppression tests and TRH, which are useful in differentiating TSHomas from the syndromes of thyroid hormone resistance. The first therapeutical approach to TSHomas is the pituitary neurosurgery. The medical treatment of TSHomas mainly rests on the administration of somatostatin analogues, such as octreotide and lanreotide, which are effective in reducing TSH secretion in more than 90% of patients with consequent normalisation of FT4 and FT3 levels and restoration of the euthyroid state.

Thyrotropinomas

Thyrotropinomas are easily recognized, owing to the availability of ultrasensitive thyropin immunometric assays. These methods allow a clear distinction between patients who have suppressed and those who have nonsuppressed circulating thyrotropin concentrations. In the latter, it is mandatory to perform a differential diagnosis, as the management of the two disorders is completely different, and failure to recognize the presence of a thyrotropinoma may result in dramatic consequences. Adenomectomy is the firstline treatment of thyrotropinomas, followed by irradiation in the case of surgical failure. Medical treatment with somatostatin analogs is effective in reducing thyrotropin secretion in more than 90% of cases.

Medical management of thyrotropin-secreting pituitary adenomas

Thyrotropin-secreting pituitary tumors (TSH-omas) are a rare cause of hyperthyroidism and account for less than 1% of all pituitary adenomas. It is however noteworthy that the number of reported cases tripled in the last years as a consequence of the routine use of ultrasensitive immunometric assays for measuring TSH levels. Contrary to previous RIAs, ultrasensitive TSH assays allow a clear distinction between patients with suppressed and those with non-suppressed circulating TSH concentrations, i.e. between patients with primary hyperthyroidism (Graves' disease or toxic nodular goiter) and those with central hyperthyroidism (TSH-oma or pituitary resistance to thyroid hormone action). Failure to recognize the presence of a TSH-oma may result in dramatic consequences, such as improper thyroid ablation that may cause the pituitary tumor volume to further expand. The medical treatment of TSH-omas mainly rests on the administration of somatostatin analogs, such as octreotide and lanreotide. In fact, administration of dopamine agonists failed to persistently block TSH secretion in almost all patients and caused tumor shrinkage only in those with combined hypersecretion of TSH and PRL. On the contrary, somatostatin analogs were effective in reducing TSH and alpha-subunit secretion in more than 90% of cases with consequent normalization of FT4 and FT3 levels and restoration of the euthyroid state in the majority of them. In about one third of patients, a clear shrinkage of tumor mass and vision improvement could be demonstrated. Tachyphylaxis, cholelithiasis and carbohydrate intolerance occurred in a minority of treated patients. Whether somatostatin analog treatment may be an alternative to surgery and/or irradiation in patients with TSH-oma remains to be established. Nonetheless, the long-acting somatostatin preparations represent a useful tool for long-term treatment of such a rare pituitary tumors.

Corticotropin- and thyrotropin-secreting pituitary microadenomas: detection by dynamic magnetic resonance imaging

Hormone-secreting pituitary microadenomas are often not visible on magnetic resonance imaging (MRI). Diagnosis requires confirmatory endocrine test results and often an invasive procedure, inferior petrosal sinus sampling (IPSS). Improved pituitary imaging may eliminate the need for IPSS in some patients, as shown in the 2 women in this report. The first patient with hirsutism, weight gain, and hypertension had intermittent elevations of urinary free cortisol, abnormal results on a low-dose dexamethasone suppression test, and positive results on a dexamethasone-suppressed ovine corticotropin-releasing hormone test (corticotropin, increase of 122%; cortisol, increase of 118%). Gadolinium-enhanced MRI showed no focal lesion, but dynamic MRI (sequential images beginning immediately after contrast injection) revealed a right-sided 5-mm microadenoma, confirmed by transsphenoidal surgery. The second patient had a goiter, anxiety, increased free thyroxine and triiodothyronine levels, and a normal thyrotropin value with no response to thyrotropin-releasing hormone. Magnetic resonance imaging showed no lesion, but dynamic MRI detected an 8-mm microadenoma. Although about 8% to 10% of healthy persons have incidental pituitary lesions that are 3 mm or larger on MRI, identification of a distinct lesion and positive results on a dexamethasone-suppressed ovine corticotropin-releasing hormone test should decrease the probability of a false-positive result on an imaging study. We recommend that dynamic MRI be performed in any patient with a suspected microadenoma, before IPSS is performed.