Acromegaly due to secretion of growth hormone by an ectopic pancreatic islet-cell tumor

Acromegaly in humans and cats: Pathophysiological, clinical and management resemblances and differences

OBJECTIVE

Acromegaly is a disorder associated with excessive levels of growth hormone (GH) and insulin-like growth factor-1 (IGF-1). In general, GH/IGF-1 excess leads to morphologic craniofacial and acral changes as well as cardiometabolic complications, but the phenotypic changes and clinical presentation of acromegaly differ across species. Here, we review the pathophysiology, clinical presentation and management of acromegaly in humans and cats, and we provide a systematic comparison between this disease across these different species.

DESIGN

A comprehensive literature review of pathophysiology, clinical features, diagnosis and management of acromegaly in humans and in cats was performed.

RESULTS

Acromegaly is associated with prominent craniofacial changes in both species: frontal bossing, enlarged nose, ears and lips, and protuberant cheekbones are typically encountered in humans, whereas increased width of the head and skull enlargement are commonly found in cats. Malocclusion, prognathism, dental diastema and upper airway obstruction by soft tissue enlargement are reported in both species, as well as continuous growth and widening of extremities resulting in osteoarticular compromise. Increase of articular joint cartilage thickness, vertebral fractures and spine malalignment is more evident in humans, while arthropathy and spondylosis deformans may also occur in cats. Generalized organomegaly is equally observed in both species. Other similarities between humans and cats with acromegaly include heart failure, ventricular hypertrophy, diabetes mellitus, and an overall increased cardiometabolic risk. In GH-secreting pituitary tumours, local compressive effects and behavioral changes are mostly observed in humans, but also present in cats. Cutis verticis gyrata and skin tags are exclusively found in humans, while palmigrade/plantigrade stance may occur in some acromegalic cats. Serum IGF-1 is used for acromegaly diagnosis in both species, but an oral glucose tolerance test with GH measurement is only useful in humans, as glucose load does not inhibit GH secretion in cats. Imaging studies are regularly performed in both species after biochemical diagnosis of acromegaly. Hypophysectomy is the first line treatment for humans and cats, although not always available in veterinary medicine.

CONCLUSION

Acromegaly in humans and cats has substantial similarities, as a result of common pathophysiological mechanisms, however species-specific features may be found.

The clinical and biochemical spectrum of ectopic acromegaly

Ectopic acromegaly is a rare condition caused by extrapituitary central or peripheral neuroendocrine tumours (NET) that hypersecrete GH or, more commonly, GHRH. It affects less than 1% of acromegaly patients and a misdiagnosis of classic acromegaly can lead to an inappropriate pituitary surgery. Four types of ectopic acromegaly have been described: 1) Central ectopic GH-secretion: Careful cross-sectional imaging is required to exclude ectopic pituitary adenomas. 2) Peripheral GH secretion: Extremely rare. 3) Central ectopic GHRH secretion: Sellar gangliocytomas immunohistochemically positive for GHRH are found after pituitary surgery. 4) Peripheral GHRH secretion: The most common type of ectopic acromegaly is due to peripheral GHRH-secreting NETs. Tumours are large and usually located in the lungs or pancreas. Pituitary hyperplasia resulting from chronic GHRH stimulation is difficult to detect or can be misinterpreted as pituitary adenoma in the MRI. Measurement of serum GHRH levels is a specific and useful diagnostic tool. Surgery of GHRH-secreting NETs is often curative.

"Micromegaly": Acromegaly with apparently normal GH, an entity on its own?

A small proportion of the patients with acromegaly present with apparently normal basal GH levels and suppressible GH levels despite increased IGF-1 levels, a pattern called micromegaly by some authors. Whether this pattern represents a distinct entity or is just an expression of acromegaly in its early stages is still a matter of debate. Nevertheless, these patients have some peculiar characteristics such as being more likely older and male, mostly harbour microadenomas or small macroadenomas, and have lower IGF-1 and postglucose GH levels. Even though, the frequency and severity of clinical signs and comorbidities are similar to those of patients with classic acromegaly. In conclusion, micromegaly seems to be a distinct clinical entity with a different biological behavior characterized by a low GH output.

Genetic diagnosis in acromegaly and gigantism: From research to clinical practice

It is usually considered that only 5% of all pituitary neuroendocrine tumours are due to inheritable causes. Since this estimate was reported, however, multiple genetic defects driving syndromic and nonsyndromic somatotrophinomas have been unveiled. This heterogeneous genetic background results in overlapping phenotypes of GH excess. Genetic tests should be part of the approach to patients with acromegaly and gigantism because they can refine the clinical diagnoses, opening the possibility to tailor the clinical conduct to each patient. Even more, genetic testing and clinical screening of at-risk individuals have a positive impact on disease outcomes, by allowing for the timely detection and treatment of somatotrophinomas at early stages. Future research should focus on determining the actual frequency of novel genetic drivers of somatotrophinomas in the general population, developing up-to-date disease-specific multi-gene panels for clinical use, and finding strategies to improve access to modern genetic testing worldwide.

[Ectopic acromegaly due to bronchial neuroendocrine tumors: the first description in Russia of three clinical cases]

 Acromegaly is a neuroendocrine disorder caused by excessive production of growth hormone (GH). In the majority of cases the cause of acromegaly is a pituitary tumor producing GH. Cases of ectopic acromegaly are much rarer. Ectopic acromegaly occurs in cases of tumors which produce growth hormone-releasing hormone (GHRH) or extrapituitary tumors which produce GH. The main sources of excessive GHRH production are neuroendocrine tumors (NETs) of the lung or pancreas. Treatment of ectopic acromegaly consists of surgical removal of the source of GHRH hyperproduction and in cases where surgery is not an option, somatostatin analogues, pegvisomant, chemotherapy, immunotherapy or radiation therapy are used.In this article three cases of ectopic acromegaly due to GHRH-producing lung NETs are presented, each of them being notable for a number of features. In the first two cases, clinical symptoms were mild, besides in the second case ectopic acromegaly was accompanied by primary hyperparathyroidism. In the third case ectopic acromegaly was accompanied by pituitary macroadenoma, and after surgical removal of the lung NET remission of acromegaly was not achieved. In all three cases, lung NETs were detected incidentally on radiologic chest screening for other conditions.

Outcomes in pituitary adenoma causing acromegaly following endoscopic endonasal transsphenoidal surgery

Objectives

The objectives of the study were to study the analysis of outcomes after endoscopic endonasal transsphenoidal surgery (EETSS) in acromegaly in terms of surgical complications, clinical improvement, endocrinological remission, achievement of prognostically critical growth hormone (GH) level, and requirement of additional treatment.

Materials and Methods

The study included 28 acromegaly patients, who underwent EETSS. A 2010 consensus criterion was used for defining remission. Assessment of prognostically critical GH level (random value <2.5 ng/ml), the extent of resection and additional treatment, was done at post-operative week (POW) 12.

Results

All adenomas were macroadenomas; with a mean volume of 16.34 cm3 (range, 0.4-99 cm3). Most adenomas had high-grade extensions. Most common suprasellar, infrasellar, anterior, and posterior extension grades were 3 (n = 13), 1 (n = 16), 1 (n = 14), and 0 (n = 20), respectively. Knosp Grade 3 was common on both sides (right, n = 9 and left, n = 8). One patient had already been operated on with EETSS, 1.5 years back from current surgery. Sixteen patients were on hormonal support, preoperatively. Four patients died during follow-up. Post-operative common complications were diabetes insipidus (DI, n = 18), cerebrospinal fluid rhinorrhea (n = 10), surgical site hematoma (n = 3), meningitis (n = 3), hydrocephalus (n = 2), and syndrome of inappropriate antidiuretic hormone (n = 1). The mean hospital stay was 11.62 days and 12.17 months were the mean follow-up period. At 12 POW, no improvement was seen in body enlargement and visual complaints, but all other complaints improved significantly except perspiration. Adenomas were decreased in all extensions except posterior and mean adenoma volume was reduced from 16.34 cm3 to 2.92 cm3 after surgery. Sub-total resection (STR, n = 10), near-total resection (NTR, n = 7), gross-total resection (GTR, n = 5), and partial resection (PR, n = 2) were achieved. Endocrinological remission and prognostically critical GH levels were attained in 29.17% (n = 7) and 66.67% (n = 16), respectively. NTR, GTR, STR, and PR were associated with 57.14%, 40%, 10%, and 0% endocrinological remission, respectively. Additional treatment was required in a total of 17 patients, three in GTR, nine in STR, three in NTR, and two in PR. Ten were treated with Gamma Knife radiosurgery along with medical treatment and seven with medical treatment alone.

Conclusion

A successful EETSS can reduce adenoma volume to achieve clinical improvement, endocrinologic remission, and prognostically critical GH level with some complications related to surgery. Pre-operative larger volume and higher extension grades affect these outcomes adversely.

Outcomes in Pituitary Adenoma Causing Acromegaly Following Endoscopic Endonasal Transsphenoidal Surgery

Objectives The objective of this study was the analysis of outcomes after endoscopic endonasal transsphenoidal surgery (EETSS) in acromegaly in terms of surgical complications, clinical improvement, endocrinological remission, achievement of prognostically critical growth hormone (GH) level, and requirement of additional treatment.

Materials and Methods The study included 28 acromegaly patients, who underwent EETSS. 2010 consensus criterion was used for defining remission. Assessment of prognostically critical GH level (random value less than 2.5 ng/mL), the extent of resection, and additional treatment was done at postoperative week (POW) 12.

Results All adenomas were macroadenomas, with the mean volume of 16.34 cm3 (range, 0.4–99 cm3). Most adenomas had high-grade extensions. Most common suprasellar, infrasellar, anterior, and posterior extension grades were 3 (n = 13), 1(n = 16), 1(n = 14), and 0 (n = 20), respectively. Knosp grade 3 was common on both sides (right, n = 9 and left, n = 8). One patient had already been operated on with EETSS, 1.5 years back from current surgery. Sixteen patients were on hormonal support, preoperatively. Four patients died during follow-up. Postoperative common complications were diabetes insipidus (n = 18), cerebrospinal fluid rhinorrhea (n = 10), surgical site hematoma (n = 3), meningitis (n = 3), hydrocephalus (n = 2), and syndrome of inappropriate antidiuretic hormone (n = 1). The mean hospital stay was 11.62 days, and 12.17 months was the mean follow-up period. At 12 POW, no improvement was seen in body enlargement and visual complaints, but all other complaints improved significantly except perspiration. Adenomas were decreased in all extensions except posterior, and mean adenoma volume was reduced from 16.34 to 2.92 cm3 after surgery. Subtotal resection (STR, n = 10), near-total resection (NTR, n = 7), gross-total resection (GTR, n = 5), and partial resection (PR, n = 2) were achieved. Endocrinological remission and prognostically critical GH levels were attained in 29.17% (n = 7) and 66.67% (n = 16), respectively. NTR, GTR, STR, and PR were associated with 57.14, 40, 10, and 0% endocrinological remission, respectively. Additional treatment was required in a total of 17 patients: 3 GTR, 9 STR, 3 NTR, and 2 PR patients. Ten patients were treated with gamma knife radiosurgery along with medical treatment and seven with medical treatment alone.

Conclusion A successful EETSS can reduce adenoma volume to achieve clinical improvement, endocrinological remission, and prognostically critical GH level with some complications related to surgery. Preoperative larger volume and higher extension grades affect these outcomes adversely.

Biochemical discrepancies in the evaluation of the somatotroph axis: Elevated GH or IGF-1 levels do not always diagnose acromegaly

The most frequent diagnosis underlying the finding of an elevated growth hormone (GH) and insulin-like growth factor-1 (IGF-1) is acromegaly due to a GH-secreting pituitary tumour. However, GH and IGF-1 levels can be discordant in patients with acromegaly due to early or partially treated disease, or there might be another cause of high GH or high IGF-1 unrelated to acromegaly, such as pre-analytical and technical pitfalls, physiological circumstances and pathological conditions. High GH and normal or low serum IGF-1, or alternatively, normal GH with elevated serum IGF-1, should be carefully assessed to avoid misinterpreting the activity of acromegaly or misdiagnosing a patient with acromegaly. We summarise here these biochemical discrepancies in the evaluation of the somatotroph axis.

Paraneoplastic autoimmune hypophysitis: An emerging concept

Pituitary autoimmunity is one of the principal causes of hypopituitarism. Additionally, hypophysitis is one of the immune-related adverse events associated with immunotherapy. Recent case-oriented research has revealed a novel type of autoimmune hypophysitis, anti-PIT-1 hypophysitis, related to isolated adrenocorticotropic hormone (ACTH) deficiency and immune checkpoint inhibitor-related hypophysitis, as a form of paraneoplastic syndrome. Under these conditions, the ectopic expression of pituitary antigens present in tumors evokes a breakdown of immune tolerance, resulting in the production of autoantibodies and autoreactive cytotoxic T cells that specifically harm pituitary cells. Consequently, an innovative clinical entity of paraneoplastic autoimmune hypophysitis has been purported. This novel concept and its underlying mechanisms provide clues for understanding the pathogenesis of autoimmune pituitary diseases and can be applied to other autoimmune diseases. This review discusses the etiology of paraneoplastic autoimmune hypophysitis and its future.

Diagnosis and Treatment of Acromegaly: An Update

Acromegaly is typically caused by a growth hormone-secreting pituitary adenoma, driving excess secretion of insulin-like growth factor 1. Acromegaly may result in a variety of cardiovascular, respiratory, endocrine, metabolic, musculoskeletal, and neoplastic comorbidities. Early diagnosis and adequate treatment are essential to mitigate excess mortality associated with acromegaly. PubMed searches were conducted using the keywords growth hormone, acromegaly, pituitary adenoma, diagnosis, treatment, pituitary surgery, medical therapy, and radiation therapy (between 1981 and 2021). The diagnosis of acromegaly is confirmed on biochemical grounds, including elevated serum insulin-like growth factor 1 and lack of growth hormone suppression after glucose administration. Pituitary magnetic resonance imaging is advised in patients with acromegaly to identify an underlying pituitary adenoma. Transsphenoidal pituitary surgery is generally first-line therapy for patients with acromegaly. However, patients with larger and invasive tumors (macroadenomas) are often not in remission postoperatively. Medical therapies, including somatostatin receptor ligands, cabergoline, and pegvisomant, can be recommended to patients with persistent disease after surgery. Select patients may also be candidates for preoperative medical therapy. In addition, primary medical therapy has a role for patients without mass effect on the optic chiasm who are unlikely to be cured by surgery. Clinical, endocrine, imaging, histologic, and molecular markers may help predict the response to medical therapy; however, confirmation in prospective studies is needed. Radiation therapy is usually a third-line option and is increasingly administered by a variety of stereotactic techniques. An improved understanding of the pathogenesis of acromegaly may ultimately lead to the design of novel, efficacious therapies for this serious condition.

Acromegaly Caused by Ectopic Growth Hormone Releasing Hormone Secretion: A Review

INTRODUCTION

Ectopic acromegaly is a rare condition caused most frequently by growth hormone releasing hormone (GHRH) secretion from neuroendocrine tumors. The diagnosis is often difficult to establish as its main symptoms do not differ from those of acromegaly of pituitary origin.

OBJECTIVES

To determine most common clinical features and diagnostic challenges in ectopic acromegaly.

PATIENTS AND METHODS

A search for ectopic acromegaly cases available in literature was performed using PubMed, Cochrane, and MEDline database. In this article, 127 cases of ectopic acromegaly described after GHRH isolation in 1982 are comprehensively reviewed, along with a summary of current state of knowledge on its clinical features, diagnostic methods, and treatment modalities. The most important data were compiled and compared in the tables.

RESULTS

Neuroendocrine tumors were confirmed in 119 out of 121 patients with histopathological evaluation, mostly of lung and pancreatic origin. Clinical manifestation comprise symptoms associated with pituitary hyperplasia, such as headache or visual field disturbances, as well as typical signs of acromegaly. Other endocrinopathies may also be present depending on the tumor type. Definitive diagnosis of ectopic acromegaly requires confirmation of GHRH secretion from a tumor using either histopathological methods or GHRH plasma concentration assessment. Hormonal evaluation was available for 84 patients (66%) and histopathological confirmation for 99 cases (78%). Complete tumor resection was the main treatment method for most patients as it is a treatment of choice due to its highest effectiveness. When not feasible, somatostatin receptor ligands (SRL) therapy is the preferred treatment option. Prognosis is relatively favorable for neuroendocrine GHRH-secreting tumors with high survival rate.

CONCLUSION

Although ectopic acromegaly remains a rare disease, one should be aware of it as a possible differential diagnosis in patients presenting with additional symptoms or those not responding to classic treatment of acromegaly.

Epidemiology of Functioning Pituitary Adenomas

Pituitary adenomas (PAs) are defined as benign monoclonal tumors in the pituitary gland that cause symptoms due to either hormonal hypersecretion or a space-occupying effect, and are classified as functioning or non-functioning. Because of their rarity and slow-growing with symptomless nature in most cases, it has been challenging to investigate the epidemiology of PAs. Considering their public health impact and association with increased morbidity and mortality, however, it is essential to understand the prevalence and incidence of PAs in order to improve patient outcomes and to minimize the resultant burden on the health care system. Fortunately, developments in imaging modalities and easier access to large-scale population data have enabled investigators to analyze the epidemiology of PAs more accurately. This review summarizes previously reported epidemiologic data on functioning PAs in Korea and other countries.

Pancreatic neuroendocrine tumors: A review of serum biomarkers, staging, and management

Pancreatic neuroendocrine tumors (pNETs) are a heterogeneous group of tumors with complicated treatment options that depend on pathological grading, clinical staging, and presence of symptoms related to hormonal secretion. With regard to diagnosis, remarkable advances have been made: Chromogranin A is recommended as a general marker for pNETs. But other new biomarker modalities, like circulating tumor cells, multiple transcript analysis, microRNA profile, and cytokines, should be clarified in future investigations before clinical application. Therefore, the currently available serum biomarkers are insufficient for diagnosis, but reasonably acceptable in evaluating the prognosis of and response to treatments during follow-up of pNETs. Surgical resection is still the only curative therapeutic option for localized pNETs. However, a debulking operation has also been proven to be effective for controlling the disease. As for drug therapy, steroids and somatostatin analogues are the first-line therapy for those with positive expression of somatostatin receptor, while everolimus and sunitinib represent important progress for the treatment of patients with advanced pNETs. Great progress has been achieved in the combination of systematic therapy with local control treatments. The optimal timing of local control intervention, planning of sequential therapies, and implementation of multidisciplinary care remain pending.

The Clinicopathological Spectrum of Acromegaly

BACKGROUND

Acromegaly results from a persistent excess in growth hormone with clinical features that may be subtle or severe. The most common cause of acromegaly is a pituitary tumor that causes excessive production of growth hormone (GH), and rare cases are due to an excess of the GH-releasing hormone (GHRH) or the ectopic production of GH.

OBJECTIVE

Discuss the different diseases that present with manifestations of GH excess and clinical acromegaly, emphasizing the distinct clinical and radiological characteristics of the different pathological entities.

METHODS

We performed a narrative review of the published clinicopathological information about acromegaly. An English-language search for relevant studies was conducted on PubMed from inception to 1 August 2019. The reference lists of relevant studies were also reviewed.

RESULTS

Pituitary tumors that cause GH excess have several variants, including pure somatotroph tumors that can be densely or sparsely granulated, or plurihormonal tumors that include mammosomatotroph, mixed somatotroph-lactotroph tumors and mature plurihomonal Pit1-lineage tumors, acidophil stem cell tumors and poorly-differentiated Pit1-lineage tumors. Each tumor type has a distinct pathophysiology, resulting in variations in clinical manifestations, imaging and responses to therapies.

CONCLUSION

Detailed clinicopathological information will be useful in the era of precision medicine, in which physicians tailor the correct treatment modality to each patient.

Acromegaly

Acromegaly is characterized by increased release of growth hormone and, consequently, insulin-like growth factor I (IGF1), most often by a pituitary adenoma. Prolonged exposure to excess hormone leads to progressive somatic disfigurement and a wide range of systemic manifestations that are associated with increased mortality. Although considered a rare disease, recent studies have reported an increased incidence of acromegaly owing to better disease awareness, improved diagnostic tools and perhaps a real increase in prevalence. Acromegaly treatment approaches, which include surgery, radiotherapy and medical therapy, have changed considerably over time owing to improved surgical procedures, development of new radiotherapy techniques and availability of new medical therapies. The optimal use of these treatments will reduce mortality in patients with acromegaly to levels in the general population. Medical therapy is currently an important treatment option and can even be the first-line treatment in patients with acromegaly who will not benefit from or are not suitable for first-line neurosurgical treatment. Pharmacological treatments include somatostatin receptor ligands (such as octreotide, lanreotide and pasireotide), dopamine agonists and the growth hormone receptor antagonist pegvisomant. In this Primer, we review the main aspects of acromegaly, including scientific advances that underlie expanding knowledge of disease pathogenesis, improvements in disease management and new medical therapies that are available and in development to improve disease control.

Role of biomarker tests for diagnosis of neuroendocrine tumours

Neuroendocrine tumours (NETs) are neoplasms that arise from neuroendocrine cells. Neuroendocrine cells and their tumours can secrete a wide range of amines and polypeptide hormones into the systemic circulation. This feature has triggered widespread investigation into circulating biomarkers for the diagnosis of NETs as well as for the prediction of the biological behaviour of tumour cells. Classic examples of circulating biomarkers for gastroenteropancreatic NETs include chromogranin A, neuron-specific enolase and pancreatic polypeptide as well as hormones that elicit clinical syndromes, such as serotonin and its metabolites, insulin, glucagon and gastrin. Biomarker metrics of general markers for diagnosing all gastroenteropancreatic NET subtypes are limited, but specific hormonal measurements can be of diagnostic value in select cases. In the past decade, methods for detecting circulating transcripts and tumour cells have been developed to improve the diagnosis of patients with NETs. Concurrently, modern scanning techniques and superior radiotracers for functional imaging have markedly expanded the options for clinicians dealing with NETs. Here, we review the latest research on biomarkers in the NET field to provide clinicians with a comprehensive overview of relevant diagnostic biomarkers that can be implemented in dedicated situations.

Acromegaly: clinical features at diagnosis

BACKGROUND

Acromegaly is a rare and underdiagnosed disorder caused, in more than 95% of cases, by a growth hormone (GH)-secreting pituitary adenoma. The GH hypersecretion leads to overproduction of insulin-like growth factor 1 (IGF-1) which results in a multisystem disease characterized by somatic overgrowth, multiple comorbidities, physical disfigurement, and increased mortality.

OBJECTIVE

This article aims to review the clinical features of acromegaly at diagnosis.

DISCUSSION/CONCLUSION

Acromegaly affects both males and females equally and the average age at diagnosis ranges from 40 to 50 years (up to 5% of cases < the age 20). Due to insidious onset and slow progression, acromegaly is often diagnosed five to more than ten years after its onset. The typical coarsening of facial features include furrowing of fronthead, pronounced brow protrusion, enlargement of the nose and the ears, thickening of the lips, skin wrinkles and nasolabial folds, as well as mandibular prognathism that leads to dental malocclusion and increased interdental spacing. Excessive growth of hands and feet (predominantly due to soft tissue swelling) is present in the vast majority of acromegalic patients. Gigantism accounts for up to 5% of cases and occurs when the excess of GH becomes manifest in the young, before the epiphyseal fusion. The disease also has rheumatologic, cardiovascular, respiratory, neoplastic, neurological, and metabolic manifestations which negatively impact its prognosis and patients quality of life. Less than 15% of acromegalic patients actively seek medical attention for change in appearance or enlargement of the extremities. The presentation of acromegaly is more often related to its systemic comorbidities or to local tumor effects.

Diagnostic challenges and management of a patient with acromegaly due to ectopic growth hormone-releasing hormone secretion from a bronchial carcinoid tumour

A male patient presented at the age of 30 with classic clinical features of acromegaly and was found to have elevated growth hormone levels, not suppressing during an oral glucose tolerance test. His acromegaly was originally considered to be of pituitary origin, based on a CT scan, which was interpreted as showing a pituitary macroadenoma. Despite two trans-sphenoidal surgeries, cranial radiotherapy and periods of treatment with bromocriptine and octreotide, his acromegaly remained active clinically and biochemically. A lung mass was discovered incidentally on a chest X-ray performed as part of a routine pre-assessment for spinal surgery 5 years following the initial presentation. This was confirmed to be a bronchial carcinoid tumour, which was strongly positive for growth hormone-releasing hormone (GHRH) and somatostatin receptor type 2 by immunohistochemistry. The re-examination of the pituitary specimens asserted the diagnosis of pituitary GH hyperplasia. Complete resolution of the patient's acromegaly was achieved following right lower and middle lobectomy. Seventeen years following the successful resection of the bronchial carcinoid tumour the patient remains under annual endocrine follow-up for monitoring of the hypopituitarism he developed after the original interventions to his pituitary gland, while there has been no evidence of active acromegaly or recurrence of the carcinoid tumour. Ectopic acromegaly is extremely rare, accounting for <1% of all cases of acromegaly. Our case highlights the diagnostic challenges differentiating between ectopic acromegaly and acromegaly of pituitary origin and emphasises the importance of avoiding unnecessary pituitary surgery and radiotherapy. The role of laboratory investigations, imaging and histology as diagnostic tools is discussed.

LEARNING POINTS

Ectopic acromegaly is rare, accounting for less than 1% of all cases of acromegaly.Ectopic acromegaly is almost always due to extra-pituitary GHRH secretion, mainly from neuroendocrine tumours of pancreatic or bronchial origin.Differentiating between acromegaly of pituitary origin and ectopic acromegaly can cause diagnostic challenges due to similarities in clinical presentation and biochemistry.Serum GHRH can be a useful diagnostic tool to diagnose ectopic acromegaly.Pituitary imaging is crucial to differentiate between a pituitary adenoma and pituitary hyperplasia, which is a common finding in ectopic acromegaly.Diagnosing ectopic acromegaly is pivotal to avoid unnecessary interventions to the pituitary and preserve normal pituitary function.

Ectopic Acromegaly Arising from a Pituitary Adenoma within the Bony Intersphenoid Septum of a Patient with Empty Sella Syndrome

Objective

 To describe the work-up and treatment of rare ectopic acromegaly caused by a biopsy-proven somatotroph pituitary adenoma located within the bony intersphenoid septum of a patient with empty sella syndrome (ESS).

Methods

 We report the presentation, clinical course, diagnostic work-up, and lesion localization and treatment challenges encountered in a 55-year-old patient, with a brief review of relevant literature.

Results

 A 55-year-old African-American man presented with acromegaly and ESS. Attempts to definitively localize the causative tumor were unsuccessful, though petrosal sinus sampling supported central growth hormone production and imaging suggested bone-enclosed subsellar pituitary tissue. Endoscopic endonasal transphenoidal exploration was undertaken with resection of a somatotroph pituitary microadenoma, and subsequent clinical improvement and biochemical remission. Retrospective review revealed the patient's pituitary to have been located ectopically within a unique bony intersphenoid septum.

Conclusion

 This report describes the first known case of an ectopic pituitary adenoma located within the midline bony intersphenoid septum, which we postulate to have resulted from anomalous embryological pituitary migration. Intra-intersphenoid septal tumors should be considered in cases of apparent central acromegaly with ESS or absence of tumor tissue within the paranasal sinuses or other peripheral locations.

Indexing

 Acromegaly, ESS, pituitary adenoma, sphenoid sinus septum.

Acromegaly in a patient with a pulmonary neuroendocrine tumor: case report and review of current literature

Background

Pulmonary neuroendocrine tumors (NET) form a heterogeneous group of rare diseases. In these tumors, paraneoplastic syndromes have been described to drive the course of the disease, among them acromegaly induced by paraneoplastic secretion of growth hormone-releasing hormone (GHRH).

Case presentation

We report the case of a 43 years old patient initially diagnosed with acromegaly accompanied by weight gain and acral enlargement. Subsequently, further diagnostic work-up identified a solitary pulmonary neuroendocrine tumor (NET). Laboratory tests revealed markedly increased growth hormone (GH) and insulin-like growth factor 1 (IGF-1) without GHRH elevation in the absence of pituitary pathologies confirming the paraneoplastic origin of clinical presentation with acromegaly. Curative surgery was performed leading to normalization of the elevated hormone levels and improvement of the clinical symptoms. Immunohistochemically, a typical carcinoid (TC) was seen with low proliferation index and abundant IGF-1 expression.

Conclusions

The association of acromegaly and pulmonary NET has only rarely been reported. We present an individual case of paraneoplastic GH- and IGF-1 secretion in a patient with pulmonary NET. Based on their rarity, the knowledge of paraneoplastic syndromes occurring in patients with pulmonary NET such as acromegaly due to paraneoplastic GH- and IGF-1 secretion is mandatory to adequately diagnose and treat these patients.

Pasireotide: a novel treatment for patients with acromegaly

Morbidity and mortality rates in patients with active acromegaly are higher than the general population. Adequate biochemical control restores mortality to normal rates. Now, medical therapy has an increasingly important role in the treatment of patients with acromegaly. Somatostatin receptor ligands (SRLs) are considered the standard medical therapy, either after surgery or as a first-line therapy when surgery is deemed ineffective or is contraindicated. Overall, octreotide and lanreotide are first-generation SRLs and are effective in ~20%-70% of patients. Pegvisomant, a growth hormone receptor antagonist, controls insulin-like growth factor 1 in 65%-90% of cases. Consequently, a subset of patients (nonresponders) requires other treatment options. Drug combination therapy offers the potential for more efficacious disease control. However, the development of new medical therapies remains essential. Here, emphasis is placed on new medical therapies to control acromegaly. There is a focus on pasireotide long-acting release (LAR) (Signifor LAR®), which was approved in 2014 by the US Food and Drug Administration and the European Medicine Agency for the treatment of acromegaly. Pasireotide LAR is a long-acting somatostatin multireceptor ligand. In a Phase III clinical trial in patients with acromegaly (naïve to medical therapy or uncontrolled on a maximum dose of first-generation SRLs), 40 and 60 mg of intramuscular pasireotide LAR achieved better biochemical disease control than octreotide LAR, and tumor shrinkage was noted in both pasireotide groups. Pasireotide LAR tolerability was similar to other SRLs, except for a greater frequency and degree of hyperglycemia and diabetes mellitus. Baseline glucose may predict hyperglycemia occurrence after treatment, and careful monitoring of glycemic status and appropriate treatment is required. A precise definition of patients with acromegaly who will derive the greatest therapeutic benefit from pasireotide LAR remains to be established. Lastly, novel therapies and new potential delivery modalities (oral octreotide) are summarized.

Ectopic acromegaly due to a growth hormone-secreting neuroendocrine-differentiated tumor developed from ovarian mature cystic teratoma

Acromegaly is a clinical syndrome caused by the overproduction of growth hormone (GH) and also known as a rare disease. Clinical, biochemical, and radiological features are often indistinguishable between GH-producing hypophysis adenomas and ectopic GH-releasing hormone (GHRH)-producing tumors. A 40-year-old woman presented to us with her growing feet, hands especially fingers, and enlarging nose. Biochemical diagnosis of acromegaly was made by measuring insulin-like growth factor-1 (IGF-1) level and glucose-suppressed GH estimation. Her spot IGF-1 level was 1300 ng/ml (90-226 ng/ml). The basal GH was 30 ng/l, and 60- and 120-min GH levels after 75-g oral glucose load were 29 and 40 ng/l, respectively. Magnetic resonance imaging (MRI) of pituitary was normal. There was no pituitary adenoma or pituitary hyperplasia. Extrapituitary ectopic hypersecretion of GH or GHRH-secreting tumor search was done by high-resolution computed tomography (CT) of chest and whole abdomen. Abdomen CT revealed 9.5 × 8 cm pelvic mass, which included calcific regions and solid component. The specimen's immunohistochemical staining with GH was positive but interestingly GHRH was negative. According to immunohistochemical staining, the patient's diagnosis was ectopic acromegaly due to a GH-secreting neuroendocrine-differentiated tumor developed from an ovarian mature cystic teratoma. Herein, we present excellent illustration of an unusual and confusing clinical scenario of ectopic acromegaly.

Ectopic acromegaly due to growth hormone releasing hormone

Acromegaly secondary to extra-pituitary tumors secreting growth hormone releasing hormone (GHRH) is rarely encountered. We review the literature on ectopic acromegaly and present the index report of ectopic acromegaly secondary to GHRH secretion from a mediastinal paraganglioma. Clinical and pathological manifestations and therapeutic management of 99 patients with ectopic acromegaly are reviewed. Acromegaly secondary to ectopic GHRH secretion is usually caused by a neuroendocrine tumor in the lung and pancreas. We report an additional cause of ectopic acromegaly from a mediastinal paraganglioma. Diagnostic criteria of ectopic GHRH syndrome include biochemical and pathologic tumoral confirmation of GHRH secretion and expression. Management of ectopic acromegaly consists of surgical resection of the primary tumor and biochemical normalization, with possible adjuvant use of somatostatin analogs. The review demonstrates that there are several tumor types, including paragangliomas which may secrete GHRH, leading to acromegaly. Clinical and laboratory manifestations of the syndrome and challenges in diagnosis and management of these rarely encountered patients require early diagnosis and appropriate treatment to prevent long-term morbidity and mortality with ectopic acromegaly.

Pancreatic neuroendocrine tumors: biology, diagnosis,and treatment

Pancreatic neuroendocrine tumors (PNETs), a group of endocrine tumors arising in the pancreas, are among the most common neuroendocrine tumors. The genetic causes of familial and sporadic PNETs are somewhat understood, but their molecular pathogenesis remains unknown. Most PNETs are indolent but have malignant potential. The biological behavior of an individual PNET is unpredictable; higher tumor grade, lymph node and liver metastasis, and larger tumor size generally indicate a less favorable prognosis. Endocrine testing, imaging, and histological evidence are necessary to accurately diagnose PNETs. A 4-pronged aggressive treatment approach consisting of surgery, locoregional therapy, systemic therapy, and complication control has become popular in academic centers around the world. The optimal application of the multiple systemic therapeutic modalities is under development; efficacy, safety, availability, and cost should be considered when treating a specific patient. The clinical presentation, diagnosis, and treatment of specific types of PNETs and familial PNET syndromes, including the novel Mahvash disease, are summarized.

Acromegaly due to an ectopic pituitary adenoma in the clivus: case report and review of literature

Pituitary adenomas rarely originate outside the sella turcica. Ectopic locations include the suprasellar region, sphenoid sinus, cavernous sinus and clivus. We describe a 50-year-old female who presented with clinical signs and biochemical evidence of acromegaly. Pituitary MRI demonstrated a 2 mm hypointense lesion on the right side of the pituitary gland. However upon drilling of the upper clival bone to expose the sella during endoscopic transsphenoidal surgery, soft tumor-like tissue was encountered within the clivus. Exploration of the sella, including the area of hypointensity noted on preoperative imaging, did not identify any other abnormality. Immunohistochemical examination of the fully resected tumor demonstrated growth hormone immunoreactivity. Failed preoperative diagnosis of this rare ectopic GH-producing tumor was compounded by the presence of a misleading pituitary abnormality consistent with a microadenoma. The epidemiology and pertinent literature of this uncommon condition is discussed.

Changes in endothelial dysfunction and associated cardiovascular disease morbidity markers in GH-IGF axis pathology

Arterial endothelial dysfunction is an early event in the pathogenesis of atherosclerosis and predisposes individuals to the deposition of unstable atherosclerotic plaques. It can also lead to increased arterial stiffness, which is an accepted cause of increased arterial pulse wave velocity (APWV). Endothelial dysfunction is reversed by recombinant human growth hormone (rhGH) therapy in patients with growth hormone (GH) deficiency (GHD), favorably influencing the risk for atherogenesis. Endogenous human growth hormone (hGH), secreted by the anterior pituitary, and levels of insulin-like growth factor-I (IGF-I), produced in response to hGH stimulation of the liver, peak during early adulthood, but decline throughout adulthood. It is suspected that low-grade inflammatory cardiovascular pathophysiologic markers such as homocysteine, nitric oxide, C-reactive protein (CRP), and fibrinogen and plasminogen activator inhibitor along with changes in lipid and glucose metabolism may all contribute to GHD-associated metabolic and cardiovascular complications. These effects are associated with increased APWV, but are attenuated by rhGH therapy in GHD. GH replacement increases IGF-I levels and reduces CRP and large-artery stiffness. Reviews of rhGH in the somatopause have not been overtly favorable. Whereas reviews of rhGH/rhIGF-I combinations in GH resistance are more positive than those for rhGH alone, their combined use in the somatopause is limited. Senescent individuals may benefit from such a combination.

Proceedings of the IASLC International Workshop on Advances in Pulmonary Neuroendocrine Tumors 2007

The International Association for the Study of Lung Cancer, (IASLC) International Congress on Advances in Pulmonary Neuroendocrine Tumors was a two-day meeting held at the Royal Brompton Hospital in London, United Kingdom on the thirteenth and forteenth of December 2007. The meeting was led by 14 member international faculty-in the disciplines of pathology, surgery, medicine, oncology, endocrinology, nuclear medicine, diagnostic imaging, and biostatistics. The aims were twofold, as an educational meeting, and to develop the IASLC International Pulmonary Neuroendocrine Tumors Registry. The meeting highlighted the difference in presentation of the tumors, management options for early and advanced stage disease including the use of novel agents and approaches. The need, process, and approach to an International Registry of Pulmonary Neuroendocrine Tumors were emphasized. International collaboration to develop a retrospective registry, prospective data collection, virtual tissue bank, and collaborative clinical trials were universally agreed as the best way to advance our understanding and treatment of these rare tumors.

Acromegaly

Acromegaly is an acquired disorder related to excessive production of growth hormone (GH) and characterized by progressive somatic disfigurement (mainly involving the face and extremities) and systemic manifestations. The prevalence is estimated at 1:140,000-250,000. It is most often diagnosed in middle-aged adults (average age 40 years, men and women equally affected). Due to insidious onset and slow progression, acromegaly is often diagnosed four to more than ten years after its onset. The main clinical features are broadened extremities (hands and feet), widened thickened and stubby fingers, and thickened soft tissue. The facial aspect is characteristic and includes a widened and thickened nose, prominent cheekbones, forehead bulges, thick lips and marked facial lines. The forehead and overlying skin is thickened, sometimes leading to frontal bossing. There is a tendency towards mandibular overgrowth with prognathism, maxillary widening, tooth separation and jaw malocclusion. The disease also has rheumatologic, cardiovascular, respiratory and metabolic consequences which determine its prognosis. In the majority of cases, acromegaly is related to a pituitary adenoma, either purely GH-secreting (60%) or mixed. In very rare cases, acromegaly is due to ectopic secretion of growth-hormone-releasing hormone (GHRH) responsible for pituitary hyperplasia. The clinical diagnosis is confirmed biochemically by an increased serum GH concentration following an oral glucose tolerance test (OGTT) and by detection of increased levels of insulin-like growth factor-I (IGF-I). Assessment of tumor volume and extension is based on imaging studies. Echocardiography and sleep apnea testing are used to determine the clinical impact of acromegaly. Treatment is aimed at correcting (or preventing) tumor compression by excising the disease-causing lesion, and at reducing GH and IGF-I levels to normal values. Transsphenoidal surgery is often the first-line treatment. When surgery fails to correct GH/IGF-I hypersecretion, medical treatment with somatostatin analogs and/or radiotherapy can be used. The GH antagonist (pegvisomant) is used in patients that are resistant to somatostatin analogs. Adequate hormonal disease control is achieved in most cases, allowing a life expectancy similar to that of the general population. However, even if patients are cured or well-controlled, sequelae (joint pain, deformities and altered quality of life) often remain.

Acromegaly secondary to growth hormone-releasing hormone secreted by an incidentally discovered pheochromocytoma

Ectopic growth hormone-releasing hormone (GHRH)-secreting tumors are rare and cause acromegaly with somatotroph hyperplasia. We report a case of acromegaly secondary to GHRH secretion by an incidentally discovered pheochromocytoma in a normotensive patient. A 23-year-old man presented with signs and symptoms of acromegaly. Laboratory evaluation confirmed the diagnosis and magnetic resonance imaging (MRI) revealed a sellar mass which was thought to be a macroadenoma and surgically resected. The patient was not cured and medical treatment was indicated. An abdominal ultrasound performed before initiation of medical treatment showed a solid/cystic lesion superiorly to the right kidney. An abdominal MRI confirmed an adrenal tumor. Hormonal workup of the adrenal incidentaloma revealed elevated urinary catecholamine and total metanephrines findings strongly suggestive of a pheochromocytoma. Acromegaly was then suspected to be due to ectopic secretion of GHRH by the tumor. Patient underwent surgical resection and histopathologic examination confirmed a pheochromocytoma which stained positively for GHRH. Also, review of the pituitary specimen confirmed somatotrophic hyperplasia. Genetic analysis of the ret proto-oncogene showed no mutation. Pituitary MRI was repeated 10 months after pheochromocytoma resection and revealed a slightly enlarged pituitary and partial empty sella. The diagnosis of acromegaly caused by ectopic production of GHRH is a challenging task. A careful histopathological examination of the surgically excised pituitary tissue has a key role to arouse the suspicion and guide the investigation of a secondary cause of acromegaly.

Etiologic aspects and management of acromegaly

Acromegaly is a systemic disease with various etiologies. It can occur as a sporadic or, more rarely, as a familial disease. Numerous complications such as endocrine, cardiovascular, respiratory, metabolic, osteoarticular and neoplastic disturbances occur and must be taken into account when establishing a therapeutic strategy. For this reason, the decision as to a treatment modality of acromegaly must be followed by a thorough evaluation of the patient and once the diagnosis of complications is settled, adequate treatment should be instituted. Follow up of the patients requires periodical re-assessment of complications’ status.

Ectopic bioactive luteinizing hormone secretion by a pancreatic endocrine tumor, manifested as luteinized granulosa-thecal cell tumor of the ovaries

Endocrine pancreatic tumors are rare neoplasms consisting of multipotent cells capable of secreting various bioactive substances causing characteristic clinical syndromes. Ovarian stromal hyperthecosis is characterized by varying degrees of luteinized stromal cell proliferation after sustained LH and/or human chorionic gonadotropin stimulation, clinically manifested by symptoms/signs of virilization resembling the polycystic ovary syndrome (PCOS). We report a case of ectopic bioactive LH production from a pancreatic endocrine tumor in a 33-yr-old woman with rapidly developing symptoms/signs of hyperandrogenism and markedly elevated serum androgen and LH levels leading to hyperthecosis and bilateral luteinized granulosa-thecal cell tumors of the ovaries. Although the patient was initially thought to have either severe PCOS or an LH-secreting pituitary tumor, an LH-producing pancreatic endocrine tumor bearing somatostatin receptors was demonstrated on scintigraphy with [111In]octreotide and abdominal imaging. Symptoms and signs of hyperandrogenism resolved after the resection of the tumor. Immunohistochemistry, in situ hybridization, and electron microscopy studies confirmed LH synthesis by the tumor cell. Although extremely rare, ectopic LH production from nonpituitary endocrine tumors should be considered in the differential diagnosis of hyperandrogenism, particularly when associated with highly elevated serum LH levels.

Cost-of-illness study in acromegalic patients in Italy

INTRODUCTION

acromegalic therapeutic goals are directed at removing the tumor, preventing tumor re-growth and reducing long-term morbidity and mortality. In this scenario, the acromegalic patient needs a variety of health resources (diagnostic tests, surgery, radiotherapy, specialist visits and drugs) for his/her cure, in order to decrease/stop the progression of the disease and to cure the co-morbid diseases. Lack of epidemiological data has suggested performing an Italian retrospective study aiming to assess the health resource consumption that is caused by acromegalic cure and the relative co-morbidities, in order to estimate the amount of the direct costs of acromegalic patients.

METHOD

a retrospective study was performed on a total of 134 patients (142 patients selected, 76 in Genoa and 66 in Turin) for a period of about 7 yr preceding the enrolment date. Only direct costs were evaluated by performing an analysis on the perspective of Italian Healthcare Service (SSN).

RESULTS

the mean total direct costs for acromegaly cure ranged from 7,968.41 to 12,533.02 Euros/yr (p < 0.01; Mann Whitney Test), respectively, for Responders and Non-Responders. The cost driver was drug (SS analogs) for acromegalic cure. The co-morbidity conditions associated to acromegalic Non-Responder patients are clearly higher than those with well-controlled disease.

CONCLUSION

the study supports the hypothesis that controlled patients drove a saving for SSN in comparison to poor control patients that use more health resources.

Current concepts in the biochemical assessment of the patient with acromegaly

Biochemical assessment of a patient for acromegaly aims to definitively establish or exclude the presence of growth hormone excess. Whether applied to a newly recognized patient or to detect residual disease after therapy, this assessment is best accomplished by measurement of both the degree of GH suppression after oral glucose administration (OGTT) and levels of the GH dependent peptide, insulin-like growth factor I (IGF-I). When measured properly and compared to a well-characterized, age-adjusted normative database, elevation of the serum IGF-I level is a sensitive and specific indicator for the presence of acromegaly or persistent disease after therapy. The diagnosis of acromegaly can be confirmed by documenting an elevated IGF-I level in combination with failure of GH to suppress after oral glucose to below 0.3 microg/l, when GH is measured with a highly sensitive and specific assay. Persistently, normal IGF-I levels along with a nadir GH <0.3 microg/l should exclude the diagnosis. In assessing disease status during or after treatment, normalization of IGF-I is an essential criterion for biochemical control. It is important to recognize that nadir GH levels are >0.3 microg/l in some healthy subjects, so this criterion alone is not diagnostic of acromegaly. Also, because of heterogeneity of clinically available GH assays, this GH criterion, which was developed with a research assay, may not be applicable to use with all other assays. A nadir GH cut off of 1 microg/l has been found to be reliable for use with some standard immunoassays. It is recommended that glucose-suppressed GH levels be interpreted in conjunction with those of IGF-I and with consideration of conditions other than acromegaly that can alter them. With greater assay standardization and the use of IGF-I levels along with new rigorous criteria for interpretation of GH suppression during a OGTT we can improve our identification of patients with acromegaly in earlier stages of the disease as well as better recognize residual disease during therapy.

Acromegaly due to ectopic secretion of GHRH by bronchial carcinoid in a patient with empty sella

GH hyperproduction due to ectopic secretion of GHRH is a rare cause of acromegaly. Since 1959, approximately 50 cases of ectopic GHRH production from extrapituitary tumors have been described. Here we report the clinical and biochemical features of a 47-yr-old Caucasian woman with ectopic GHRH syndrome sustained by a bronchial carcinoid. The criteria for the diagnosis of acromegaly due to ectopic GHRH secretion were satisfied in our patient (i.e. confirmation of active GH hypersecretion, unequivocal demonstration of GHRH production and secretion from an extrapituitary tumor and cure of acromegaly after neoplasm removal). The tumor was an atypical carcinoid and there was a familial history of lung and colorectal cancer. Acromegaly was slightly active (mean GH value: 7.4 ng/ml, IGF-I: 436 ng/ml) and after tumor removal there was a progressive decline of GH levels, consistent with remission of pituitary somatotroph hyperplasia. Pituitary radiology showed an empty sella demonstrating for the first time its association with ectopic GHRH syndrome.

Locally produced growth hormone in canine insulinomas

The production and release of GH has been demonstrated in a variety of extra-pituitary tissues. In this respect insulin-producing pancreatic tumours are also of interest because it has been observed that GH may promote islet cell proliferation. However, these effects have only been related to GH of pituitary origin and the possibility of local production of GH with autocrine-/paracrine effects has not been considered. In this study, a reverse transcriptase polymerase chain reaction (RT-PCR) was used to demonstrate the presence of GH mRNA in pancreatic tissue of five healthy dogs and insulinomas of 14 dogs. After Southern blotting of the RT-PCR products, blots were hybridized using a canine-specific GH-probe and quantified using phosphor imaging. GH gene expression was further demonstrated by in situ hybridization using a canine digoxigenin-labelled GH-specific cDNA probe. In addition, GH immunohistochemistry was performed. In five samples of normal pancreatic tissue a weak hybridization signal was found. This signal was significantly higher in nine of 12 primary tumours. In ten of 11 metastases there was a positive hybridization signal, and this signal was also significantly higher than in the primary tumours. In situ hybridization in one sample demonstrated that GH mRNA was only produced in the tumour cells. The local production of GH was confirmed by positive staining of tumour tissue with anti-GH antibodies in ten of 12 samples. It is concluded that canine insulinomas express the gene encoding GH mRNA. The locally produced GH may have an autocrine/paracrine effect on tumour progression. The relatively high expression levels in metastases of these tumours may be related to the low inhibitory influence of somatostatin outside the pancreas.

Ectopic pancreatic tissue presenting as submucosal gastric mass

BACKGROUND

Ectopic pancreas is pancreatic tissue found outside its usual anatomic location without connection to the normal pancreas. We describe the presentation and minimally invasive management of four patients with ectopic pancreatic tissue in the stomach.

METHODS

Data were collected from a retrospective chart review of four patients undergoing laparoscopic resection of gastric pancreatic rests.

RESULTS

Four patients underwent laparoscopic resection of gastric pancreatic tissue. All patients were discharged on postoperative day 3. No complications developed.

CONCLUSION

Laparoscopic gastric wedge resection is a safe and effective treatment for symptomatic pancreatic rests located in the stomach.

Acromegaly associated with a granular cell tumor of the neurohypophysis: a clinical and histological study. Case report

Acromegaly is usually caused by a growth hormone (GH)-secreting pituitary adenoma, and hypersecretion of GH-releasing hormone (GHRH) from a hypothalamic or neuroendocrine tumor accounts for other cases. The authors report on the unusual association of acromegaly with a granular cell tumor of the neurohypophysis. A 42-year-old woman with a 10-year history of acral enlargement, headache, and menstrual abnormalities was referred to our department for a suspected GH-secreting pituitary adenoma. The patient's basal GH levels were mildly elevated at 4.8 microg/L, were not suppressed in response to an oral glucose tolerance test, and increased paradoxically after administration of thyrotropin-releasing hormone. The patient's insulin-like growth factor-1 (IGF-1) level was elevated at 462 microg/L, whereas a magnetic resonance image of the sella turcica revealed an intra- and suprasellar lesion that was compatible with a diagnosis of pituitary adenoma. A transsphenoidal approach to remove the lesion, which was mainly suprasellar, was successful during a second operative attempt, resulting in the clinical and biochemical regression of the patient's acromegaly. Four months postoperatively, the patient's basal GH level was 0.9 microg/L and her IGF-1 level was 140 microg/L. Histological analysis of the operative specimen demonstrated a granular cell tumor of the neurohypophysis, which when stained proved negative for pituitary hormones and GHRH. This case represents the first reported association between a granular cell tumor of the neurohypophysis and acromegaly. Granular cell tumor of the neurohypophysis could be added to the restricted list of neoplastic causes of acromegaly secondary to hypersecretion of a GH-releasing substance.

Epidemiology of acromegaly

Acromegaly is a consequence of chronic growth hormone (GH) excess, due in the majority of cases to a GH-secreting pituitary adenoma, and occurring with a population prevalence of 60 per million and an incidence of 3-4 per million per year. Males and females appear to be equally affected with an average age of presentation of 44 years. Younger patients may have more aggressive tumours and higher GH concentrations. There is co-existent hyperprolactinaemia in about one third of cases, and a variable proportion of [figure: see text] tumours appear to have activating mutations of the gsp gene or other genetic abnormalities. Acute complications such as carpal tunnel syndrome, sweating and obstructive sleep apnoea are usually readily reversible with treatment of the condition, but chronic complications such as hypertension, diabetes and heart disease are less readily corrected and post-treatment GH levels of < 2.5 ug/L (5 mU/L) are needed to achieve the prevalence found in the general community. Such 'curative' levels of GH are achieved in only about 50% of patients with current therapies, and as a result there is an ongoing excess of patients with chronic complications of acromegaly leading to increased morbidity and mortality from the disorder, with observed-to-expected mortality ratios ranging from 1.6-3.3 and only approaching unity in those with growth hormone levels < 2.5 ug/L following treatment. Prognostic factors include in some studies the presence of diabetes and [table: see text] hypertension prior to diagnosis as well as measures of exposure to excessive growth hormone derived from the product of preoperative serum GH and the time from first symptoms to treatment. Overall, however, the most important prognostic variable appears to be the serum GH concentration achieved by treatment, with an increasing consensus that this needs to be < 2.5 ug/L (5 mU/L) to achieve cure of the condition.

Clinical characteristics of acromegaly in Hong Kong

This study analyses the clinical characteristics of acromegalic patients in Hong Kong. All patients with acromegaly under follow up in Prince of Wales Hospital, Hong Kong between January 1984 and December 1992 were reviewed retrospectively. Detailed hospital notes were available for review in 28 out of 34. Of the 28 patients with full records available, 27 were Chinese and 1 was Nepalese. There were 8 (28.6%) males and 20 (71.4%) females. The mean age (+/- SD) at presentation was 51.2+/-16.8 years (range: 28 to 84 years) (male, 49.9+/-13.9 years [range: 28-66]; female, 51.7+/-18.1 years [range: 31-84]; p-value: NS). The commonest mode of presentation (n=22, 78.6%) was clinical suspicion by medical staff during consultation for other conditions, acromegaly being later confirmed. The estimated duration of symptoms, before diagnosis, was 14 years (range: 1 to 30 years). CT scan imaging of the pituitary gland showed that 12 patients (42.9%) had pituitary macro-adenomas (> or =1 cm), 3 (10.7%) had micro-adenomas (<1 cm), 6 (21.4%) had normal imaging, 1 (3.6%) had an empty sella and 6 (21.4%) had suspicious but inconclusive lesions in the pituitary gland. Surgery was offered as initial treatment to all patients. 4 to 6 weeks after surgery, if the maximal growth hormone response following glucose loading exceeded 10 microg/L, radiotherapy was offered. Of the 28 patients, 13 received surgery and radiotherapy, 2 surgery only, 4 radiotherapy only, 4 no treatment and 5 defaulted. At presentation, 50% had some abnormality of glucose tolerance. The mean early morning fasting baseline growth hormone was 52.8+/-37.0 microg/L (mean +/- SD, median: 48.1 microg/L) and the maximal growth hormone response during an extended oral glucose tolerance test was 63.2+/-34.9 microg/L (median: 61.3 microg/L). Forty five percents of patients had a maximal growth hormone response exceeding 60 microg/L. Of the 19 patients who underwent surgery and/or radiotherapy, 15 had their pituitary function reassessed 6 months after intervention. Their early morning fasting growth hormone and maximal growth hormone response in an extended oral glucose tolerance test were 21.3+/-25.8 and 35.4+/-37.5 microg/L, respectively. In conclusion, acromegaly in Hong Kong has an estimated annual incidence of 3.8 per million. There is a female preponderance, tendency to late presentation (>10 years) and low number of large tumors. Up to 80% were referred following observer suspicion.