Somatotroph hyperplasia. Successful treatment of acromegaly by removal of a pancreatic islet tumor secreting a growth hormone-releasing factor

Pancreatic GHRHomas in Patients with or without Multiple Endocrine Neoplasia Type 1 (MEN 1) : An Analysis of 36 Reported Cases

Pancreatic GHRHomas (pGHRHomas) with acromegaly have unique conditions, harboring the existence of multiple endocrine neoplasia type 1 (MEN 1). Moreover, pituitary lesions are affected by both protracted ectopic GHRH and loss of menin function. Of significance is the clarification of clinicopathological aspects of pGHRHomas in patients with or without MEN 1. From 1977-2016, thirty-six patients with pGHRHomas were reported. Twenty-two out of 36 patients (61%) had pGHRHomas with MEN 1 and 14 patients did not. The former had a tendency of male predominance, benign tumor behavior and fewer metastasis rather than the latter. The latter is a single pGHRHoma accompanied by pituitary enlargement with somatotroph hyperplasia (hyperplasia) caused by protracted ectopic GHRH. Nine patients with MEN 1 underwent transsphenoidal surgery (TSS). The hyperplasia associated with various pituitary adenomas (PAs) including three GH-related adenomas was observed in seven subjects (32%). In these patients, the resection of their pGHRHomas was feasible. Furthermore, all patients with acromegaly due to pGHRHomas without MEN 1 had non-TSS, whereas approximately 70% of those with MEN 1 had unnecessary TSS. The association with hyperplasia and various PAs suggested that formation of the three GH-related adenomas may be induced by the foundations of MEN 1 gene mutations. J. Med. Invest. 71 : 1-8, February, 2024.

Clinical Biology of the Pituitary Adenoma

All endocrine glands are susceptible to neoplastic growth, yet the health consequences of these neoplasms differ between endocrine tissues. Pituitary neoplasms are highly prevalent and overwhelmingly benign, exhibiting a spectrum of diverse behaviors and impact on health. To understand the clinical biology of these common yet often innocuous neoplasms, we review pituitary physiology and adenoma epidemiology, pathophysiology, behavior, and clinical consequences. The anterior pituitary develops in response to a range of complex brain signals integrating with intrinsic ectodermal cell transcriptional events that together determine gland growth, cell type differentiation, and hormonal production, in turn maintaining optimal endocrine health. Pituitary adenomas occur in 10% of the population; however, the overwhelming majority remain harmless during life. Triggered by somatic or germline mutations, disease-causing adenomas manifest pathogenic mechanisms that disrupt intrapituitary signaling to promote benign cell proliferation associated with chromosomal instability. Cellular senescence acts as a mechanistic buffer protecting against malignant transformation, an extremely rare event. It is estimated that fewer than one-thousandth of all pituitary adenomas cause clinically significant disease. Adenomas variably and adversely affect morbidity and mortality depending on cell type, hormone secretory activity, and growth behavior. For most clinically apparent adenomas, multimodal therapy controlling hormone secretion and adenoma growth lead to improved quality of life and normalized mortality. The clinical biology of pituitary adenomas, and particularly their benign nature, stands in marked contrast to other tumors of the endocrine system, such as thyroid and neuroendocrine tumors.

The state of Sergipe contribution to GH research: from Souza Leite to Itabaianinha syndrome

In the late 19^th century, José Dantas de Souza Leite, a physician born in Sergipe, published the first detailed clinical description of acromegaly under the guidance of the French neurologist Pierre Marie. In 2014, the Brazilian Society of Endocrinology and Metabolism created the "José Dantas de Souza Leite Award", which is granted every two years to a Brazilian researcher who has contributed to the development of endocrinology. In 2022, the award was given to another physician from Sergipe, Manuel Hermínio de Aguiar Oliveira, from the Federal University of Sergipe for the description of "Itabaianinha syndrome" in a cohort of individuals with isolated GH deficiency due to a homozygous inactivating mutation in the GH-releasing hormone receptor gene. This research, which was carried out over almost 30 years, was performed in partnership with Roberto Salvatori from Johns Hopkins University and in collaboration with other researchers around the world. This review article tells the story of Souza Leite, some milestones in the history of GH, and summarizes the description of Itabaianinha syndrome.

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.

Surgery for acromegaly: Indications and goals

Acromegaly is a disease that occurs secondary to high levels of GH, most often from a hormone-secreting pituitary adenoma, with multisystem adverse effects. Diagnosis includes serum GH and IGF-1 levels, and obtaining an MRI pituitary protocol to assess for a functional pituitary adenoma. Attempted gross total resection of the GH-secreting adenoma is the gold standard in treatment for patients with acromegaly for a goal of biochemical remission. Medical and radiation therapies are available when patients do not achieve biochemical cure after surgical therapy.

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.

DNA damage and growth hormone hypersecretion in pituitary somatotroph adenomas

Drivers of sporadic benign pituitary adenoma growth are largely unknown. Whole-exome sequencing of 159 prospectively resected pituitary adenomas showed that somatic copy number alteration (SCNA) rather than mutation is a hallmark of hormone-secreting adenomas and that SCNAs correlate with adenoma phenotype. Using single-gene SCNA pathway analysis, we observed that both cAMP and Fanconi anemia DNA damage repair pathways were affected by SCNAs in growth hormone-secreting (GH-secreting) somatotroph adenomas. As somatotroph differentiation and GH secretion are dependent on cAMP activation and we previously showed DNA damage, aneuploidy, and senescence in somatotroph adenomas, we studied links between cAMP signaling and DNA damage. Stimulation of cAMP in C57BL/6 mouse primary pituitary cultures using forskolin or a long-acting GH-releasing hormone (GHRH) analog increased GH production and DNA damage measured by H2AX phosphorylation and a comet assay. Octreotide, a somatostatin receptor ligand that targets somatotroph adenoma GH secretion in patients with acromegaly, inhibited cAMP and GH and reversed DNA damage induction. In vivo long-acting GHRH treatment also induced pituitary DNA damage in mice. We conclude that cAMP, which induces somatotroph proliferation and GH secretion, may concomitantly induce DNA damage, potentially linking hormone hypersecretion to SCNA and genome instability. These results elucidating somatotroph adenoma pathophysiology identify pathways for targeted treatment.

Oncogene-induced DNA damage: cyclic AMP steps into the ring

Growth hormone-secreting (GH-secreting) pituitary tumors are driven by oncogenes that induce cAMP signaling. In this issue of the JCI, Ben-Shlomo et al. performed a whole-exome study of pituitary adenomas. GH-secreting tumors had a high frequency of whole chromosome or chromosome arm copy number alterations and were associated with an increase in the tumor protein p53 and the cyclin-dependent kinase inhibitor p21WAF1/CIP1, which are findings consistent with induction of a response to DNA damage. Further, treatment of mouse pituitary cells with cAMP pathway agonists in vitro and in vivo elicited biomarkers of DNA replication stress or double-strand breaks. The findings of Ben Shlomo et al. indicate that oncoproteins that drive constitutively high cAMP signaling pathway output in susceptible cell types can elicit DNA replication stress and may promote genomic instability.

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.

Hypothalamic- and pituitary-derived growth and reproductive hormones and the control of energy balance in fish

Most endocrine systems in the body are influenced by the hypothalamic-pituitary axis. Within this axis, the hypothalamus delivers precise signals to the pituitary gland, which in turn releases hormones that directly affect target tissues including the liver, thyroid gland, adrenal glands and gonads. This action modulates the release of additional hormones from the sites of action, regulating key physiological processes, including growth, metabolism, stress and reproduction. Pituitary hormones are released by five distinct hormone-producing cell types: somatotropes (which produce growth hormone), thyrotropes (thyrotropin), corticotropes (adrenocorticotropin), lactotropes (prolactin) and gonadotropes (follicle stimulating hormone and luteinizing hormone), each modulated by specific hypothalamic signals. This careful and distinct organization of the hypothalamo-pituitary axis has been classically associated with the existence of many lineal axes (e.g., the hypothalamic-pituitary-gonadal axis) in charge of the control of the different physiological processes. While this traditional concept is valid, it is becoming apparent that hormones produced by the hypothalamo-pituitary axis have diverse effects. For instance, gonadotropin-releasing hormone II has been associated with a suppressive effect on food intake in fish. Likewise, growth hormone has been shown to influence appetite, swimming activity and aggressive behavior in fish. This review will focus on the hypothalamic and pituitary hormones classically involved in regulating growth and reproduction, and will attempt to provide a general overview of the current knowledge on their actions on energy balance and appetite in fish. It will also give a brief perspective of the role of some of these peptides in integrating feeding, metabolism, growth and reproduction.

REDUCTION IN THYMOMA SIZE AFTER PITUITARY SURGERY FOR GROWTH HORMONE-SECRETING TUMOR

Objective

A thymoma is a rare tumor of the anterior mediastinum and may be under the control of prolactin and growth hormone (GH), as well as GH-insulin-like growth factor 1 (IGF-1)-mediated paracrine and autocrine pathways. The following case report highlights the unexpected outcome in a patient with a mediastinal thymoma after pituitary surgery for a GH-producing macroadenoma.

Methods

A 58-year-old Caucasian man with a history of acromegaly caused by a pituitary macroadenoma presented with a mediastinal thymoma (proven by biopsy). The thymoma was monitored annually by imaging studies, as the patient was asymptomatic and had declined surgery. The octreotide scan was negative and tests ruled out a GH-releasing hormone (GHRH)-producing tumor. Transsphenoidal surgery for removal of the pituitary tumor was performed.

Results

Following surgery, the patient's IGF-1 levels normalized and GH was adequately suppressed in an oral glucose tolerance test. Follow-up imaging after 6 weeks and 10 months of surgery showed the absence of a pituitary tumor and a marked reduction in size of the mediastinal thymoma.

Conclusion

In a patient with acromegaly and a thymoma, surgical treatment of the GH-producing tumor might be expected to cause a reduction in thymoma size. Therefore, such tumors in patients with acromegaly may simply be monitored clinically.

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.

The robustness of diagnostic tests for GH deficiency in adults

Since the 1970s, GH treatment has been an important tool in paediatric endocrinology for the management of growth retardation. It is now accepted that adults with severe GH deficiency (GHD) demonstrate impaired physical and psychological well-being and may benefit from replacement therapy with recombinant human GH. There is, however, an ongoing debate on how to diagnose GHD, especially in adults. A GH response below the cut-off limit of a GH-stimulation test is required in most cases for establishing GHD in adults. No 'gold standard' GH-stimulation test exists, but some GH stimulation tests may be more robust to variations in patient characteristics such as age and gender, as well as to pre-test conditions like heat exposure due to a hot bath or bicycling. However, body mass index (BMI) is negatively associated with GH-responses to all available GH-stimulation tests and glucocorticoid treatment, including conventional substitution therapy, influences the GH-responses. Recently, the role of IGF-I measurements in the clinical decision making has been discussed. The aim of this review is to discuss the available GH-stimulation tests. In this author's opinion, tests which include growth-hormone-releasing hormone (GHRH) tend to be more potent and robust, especially the GHRH+arginine test which has been proven to be of clinical use. In contrast, the insulin tolerance test (ITT) and the glucagon test appear to have too many drawbacks.

Studying Cat (Felis catus) Diabetes: Beware of the Acromegalic Imposter

Naturally occurring diabetes mellitus (DM) is common in domestic cats (Felis catus). It has been proposed as a model for human Type 2 DM given many shared features. Small case studies demonstrate feline DM also occurs as a result of insulin resistance due to a somatotrophinoma. The current study estimates the prevalence of hypersomatotropism or acromegaly in the largest cohort of diabetic cats to date, evaluates clinical presentation and ease of recognition. Diabetic cats were screened for hypersomatotropism using serum total insulin-like growth factor-1 (IGF-1; radioimmunoassay), followed by further evaluation of a subset of cases with suggestive IGF-1 (>1000 ng/ml) through pituitary imaging and/ or histopathology. Clinicians indicated pre-test suspicion for hypersomatotropism. In total 1221 diabetic cats were screened; 319 (26.1%) demonstrated a serum IGF-1>1000 ng/ml (95% confidence interval: 23.6–28.6%). Of these cats a subset of 63 (20%) underwent pituitary imaging and 56/63 (89%) had a pituitary tumour on computed tomography; an additional three on magnetic resonance imaging and one on necropsy. These data suggest a positive predictive value of serum IGF-1 for hypersomatotropism of 95% (95% confidence interval: 90–100%), thus suggesting the overall hypersomatotropism prevalence among UK diabetic cats to be 24.8% (95% confidence interval: 21.2–28.6%). Only 24% of clinicians indicated a strong pre-test suspicion; most hypersomatotropism cats did not display typical phenotypical acromegaly signs. The current data suggest hypersomatotropism screening should be considered when studying diabetic cats and opportunities exist for comparative acromegaly research, especially in light of the many detected communalities with the human disease.

Medical management of functioning pituitary adenoma: an update

The treatment of functioning pituitary adenoma (FPA) must achieve endocrinological remission as well as tumor size reduction. The first-line treatment of FPA except prolactinoma is transsphenoidal surgery (TSS). Medical treatments and/or radiation will be applied as adjuvant therapies succeeding to TSS. In patients with prolactinoma, dopamine agonists, especially cabergoline, are quite efficient. Dopamine agonists decrease plasma prolactin levels and induce shrinkage in most patients and can be ceased in some of them. In patients with acromegaly, dopamine agonists, somatostatin analogues, and growth hormone receptor antagonist have been used as a monotherapy or the combination, and the high remission rate can be achieved. Pasireotide having high affinity to type 5 somatostatin receptors will be available for the patients presenting resistance against type 2 receptor agonists, such as octreotide and lanreotide. The preceding treatment with somatostatin analogues is beneficial for improving the success rate of TSS. The chimera compounds of somatostatin analogues and dopamine agonists have been investigated. The medical treatments of Cushing's disease are challenging, if TSS is not successful. To suppress ACTH secretion, dopamine agonists and somatostatin analogues have been examined, but neither came to show a sufficient effect. Pasireotide reduces urinary cortisol excretion with a high remission rate. Adrenal enzyme inhibitors (AEIs), such as metyrapone, can inhibit cortisol synthesis form adrenal glands promptly and sufficiently in most of patients. LCI699, a newly developed AEI, is more potent than metyrapone and will be available. We should use available medical treatments for improving the prognosis and quality of life.

Medical management of functioning pituitary adenoma: an update

The treatment of functioning pituitary adenoma (FPA) must achieve endocrinological remission as well as tumor size reduction. The first-line treatment of FPA except prolactinoma is transsphenoidal surgery (TSS). Medical treatments and/or radiation will be applied as adjuvant therapies succeeding to TSS. In patients with prolactinoma, dopamine agonists, especially cabergoline, are quite efficient. Dopamine agonists decrease plasma prolactin levels and induce shrinkage in most patients and can be ceased in some of them. In patients with acromegaly, dopamine agonists, somatostatin analogues, and growth hormone receptor antagonist have been used as a monotherapy or the combination, and the high remission rate can be achieved. Pasireotide having high affinity to type 5 somatostatin receptors will be available for the patients presenting resistance against type 2 receptor agonists, such as octreotide and lanreotide. The preceding treatment with somatostatin analogues is beneficial for improving the success rate of TSS. The chimera compounds of somatostatin analogues and dopamine agonists have been investigated. The medical treatments of Cushing's disease are challenging, if TSS is not successful. To suppress ACTH secretion, dopamine agonists and somatostatin analogues have been examined, but neither came to show a sufficient effect. Pasireotide reduces urinary cortisol excretion with a high remission rate. Adrenal enzyme inhibitors (AEIs), such as metyrapone, can inhibit cortisol synthesis form adrenal glands promptly and sufficiently in most of patients. LCI699, a newly developed AEI, is more potent than metyrapone and will be available. We should use available medical treatments for improving the prognosis and quality of life.

A tale of two tumors: treating pancreatic and extrapancreatic neuroendocrine tumors

Despite their perceived rarity, gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rising in incidence and prevalence. The biology, natural history, and therapeutic options for GEP-NETs are heterogeneous: NETs arising in the pancreas can be distinguished from those arising elsewhere in the gastrointestinal tract, and therapy is dichotomized between these two groups. Somatostatin analogues are the mainstay of oncologic management of bowel NETs; everolimus, streptozocin, and sunitinib are approved to treat pancreatic NETs. There are significant differences in molecular genetics between pancreatic and extrapancreatic NETs, and studies are evaluating whether additional NET patients may benefit from targeted agents. We discuss the distinguishing features of these two groups of tumors, as well as the therapeutic implications of the distinction. We also examine the evolving therapeutic landscape and discuss the likelihood that treatment will be developed independently for pancreatic and extrapancreatic gastrointestinal NETs, with novel therapeutics effective for newly identified pathologically or molecularly defined subgroups.

Epidemiology and etiopathogenesis of pituitary adenomas

Pituitary adenomas are usually benign monoclonal tumours presenting either due to hypersecretion of pituitary hormones, and/or due to local space occupying effects and hyposecretion of some or all of the pituitary hormones. Some pituitary adenomas cause prominent symptoms, while others may result in slowly developing, insidious, non-specific complains delaying accurate diagnosis, with a third group remaining symptomless and recognised only incidentally. Therefore, it is a challenge to accurately determine the prevalence and incidence of pituitary adenomas in the general population. The vast majority of pituitary adenomas occur sporadically, but familial cases are now increasingly recognised. Hereditary predisposition, somatic mutations and endocrine factors were shown to have a pathophysiologic role in the initiation and progression of pituitary adenomas, which interestingly almost always remain benign. Here, we summarize the available epidemiological data and the known pathogenesis of the pituitary adenomas.

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.

Metabolic effects of a growth hormone-releasing factor in obese subjects with reduced growth hormone secretion: a randomized controlled trial

CONTEXT

Obesity is associated with reduced GH secretion and increased cardiovascular disease risk.

OBJECTIVE

We performed this study to determine the effects of augmenting endogenous GH secretion on body composition and cardiovascular disease risk indices in obese subjects with reduced GH secretion.

DESIGN, PATIENTS AND METHODS

A randomized, double-blind, placebo-controlled study was performed involving 60 abdominally obese subjects with reduced GH secretion. Subjects received tesamorelin, a GHRH(1-44) analog, 2 mg once daily, or placebo for 12 months. Abdominal visceral adipose tissue (VAT) was assessed by abdominal computed tomography scan, and carotid intima-media thickness (cIMT) was assessed by ultrasound. Treatment effect was determined by longitudinal linear mixed-effects modeling.

RESULTS

VAT [-16 ± 9 vs.19 ± 9 cm(2), tesamorelin vs. placebo; treatment effect (95% confidence interval): -35 (-58, -12) cm(2); P = 0.003], cIMT (-0.03 ± 0.01 vs. 0.01 ± 0.01 mm; -0.04 (-0.07, -0.01) mm; P = 0.02), log C-reactive protein (-0.17 ± 0.04 vs. -0.03 ± 0.05 mg/liter; -0.15 (-0.30, -0.01) mg/liter, P = 0.04), and triglycerides (-26 ± 16 vs. 12 ± 8 mg/dl; -37 (-67, -7) mg/dl; P = 0.02) improved significantly in the tesamorelin group vs. placebo. No significant effects on abdominal sc adipose tissue (-6 ± 6 vs. 3 ± 11 cm(2); -10 (-32, +13) cm(2); P = 0.40) were seen. IGF-I increased (86 ± 21 vs. -6 ± 8 μg/liter; 92 (+52, +132) μg/liter; P < 0.0001). No changes in fasting, 2-h glucose, or glycated hemoglobin were seen. There were no serious adverse events or differences in adverse events between the groups.

CONCLUSION

Among obese subjects with relative reductions in GH, tesamorelin selectively reduces VAT without significant effects on sc adipose tissue and improves triglycerides, C-reactive protein, and cIMT, without aggravating glucose.

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.

Acromegaly induced by ectopic secretion of GHRH: a review 30 years after GHRH discovery

Ectopic acromegaly is very rare and since the discovery of growth hormone-releasing hormone (GHRH), 30 years ago, only 74 cases have been reported in the literature. Except for a recent French series of 21 cases, most of them were case reports. The present review summarizes the current knowledge on clinical presentation, diagnosis and prognosis. Tumors secreting GHRH are neuroendocrine tumors, usually well differentiated and mainly from pancreatic or bronchial origin. They are usually large and easy to localize using TDM and somatostatin receptor scintigraphy. Clinical presentation is an acromegaly of variable intensity, whose features are similar to that of a somatotropic adenoma. Pituitary may be normal or enlarged at MRI which may be difficult to interpret especially in MEN1 patients where the association of a microprolactinoma to a pancreatic tumor secreting GHRH may be misleading. GHRH plasmatic measurement has an excellent specificity for the diagnosis, using a threshold of 250 to 300ng/L and is a good tool for follow-up of patients after treatment. These tumors have a good overall prognosis, even in metastatic forms which represent 50% of cases. Surgical approach is recommended and, when a complete tumoral resection is feasible, results, in most patients, in long-lasting remission. In such cases, GHRH concentration is normalized and its increase is an accurate indicator of recurrence. In uncured patients, somatostatin analogs control GH secretion but inhibit, only partially, GHRH secretion. MEN1 mutation should be systematically investigated in patients with a pancreatic tumor.

Clinical characteristics and outcome of acromegaly induced by ectopic secretion of growth hormone-releasing hormone (GHRH): a French nationwide series of 21 cases

CONTEXT

Ectopic GHRH secretion is a rare cause of acromegaly, and case reports are mainly isolated.

SETTING

From the registry of the sole laboratory performing plasma GHRH assays in France, we identified cases of ectopic GHRH secretion presenting with acromegaly between 1983 and 2008.

PATIENTS

Twenty-one patients aged 14-77 yr were identified from 12 French hospitals. Median GHRH was 548 (270-9779) ng/liter.

MAIN OUTCOME MEASURES

Outcome measures included description of tumor features and outcome and the relation between plasma GHRH values and tumor site, size, and spread.

RESULTS

The primary neuroendocrine tumor was identified for 20 of 21 patients (12 pancreatic, seven bronchial, one appendicular). Tumors were large (10-80 mm), identified on computed tomography scan in 18 cases and by endoscopic ultrasound and somatostatin receptor scintigraphy in two. Somatostatin receptor scintigraphy had a similar sensitivity to computed tomography scan (81 vs. 86%). Tumors were all well differentiated; 47.6% had metastasized at the time of diagnosis of acromegaly. After a median follow-up of 5 yr, 85% of patients were alive. Ninety-one percent of patients whose tumor was completely removed were considered in remission, and most had normalized plasma GHRH. The remaining patients were treated with somatostatin analogs: IGF-I normalized except for one patient who required pegvisomant, but GHRH levels remained elevated. No correlations were found between GHRH levels and tumor site or size or the existence of metastases. Identification of increased plasma GHRH during follow-up was an accurate indicator of recurrence.

CONCLUSIONS

The prognosis of endocrine tumors responsible for GHRH secretion appears relatively good. Plasma GHRH assay is an accurate tool for diagnosis and follow-up.

Conversion of daily pegvisomant to weekly pegvisomant combined with long-acting somatostatin analogs, in controlled acromegaly patients

The efficacy of combined treatment in active acromegaly with both long-acting somatostatin analogs (SRIF) and pegvisomant (PEG-V) has been well established. The aim was to describe the PEG-V dose reductions after the conversion from daily PEG-V to combination treatment. To clarify the individual beneficial and adverse effects, in two acromegaly patients, who only normalized their insulin like growth factor (IGF-I) levels with high-dose pegvisomant therapy. We present two cases of a 31 and 44 years old male with gigantism and acromegaly that were controlled subsequently by surgery, radiotherapy, SRIF analogs and daily PEG-V treatment. They were converted to combined treatment of monthly SSA and (twice) weekly PEG-V. High dose SSA treatment was added while the PEG-V dose was decreased during carful monitoring of the IGF-I. After switching from PEG-V monotherapy to SRIF analogs plus pegvisomant combination therapy IGF-I remained normal. However, the necessary PEG-V dose, to normalize IGF-I differed significantly between these two patients. One patient needed twice weekly 100 mg, the second needed 60 mg once weekly on top of their monthly lanreotide Autosolution injections of 120 mg. The weekly dose reduction was 80 and 150 mg. After the introducing of lanreotide, fasting glucose and glycosylated haemoglobin concentrations increased. Diabetic medication had to be introduced or increased. No changes in liver tests or in pituitary adenoma size were observed. In these two patients, PEG-V in combination with long-acting SRIF analogs was as effective as PEG-V monotherapy in normalizing IGF-I levels, although significant dose-reductions in PEG-V could be achieved. However, there seems to be a wide variation in the reduction of PEG-V dose, which can be obtained after conversion to combined treatment.

Growth hormone-releasing hormone: not only a neurohormone

Growth hormone-releasing hormone (GHRH) is mostly thought to act by stimulating the production and release of growth hormone from the pituitary. However, this neuropeptide emerges as a rather pleiotropic hormone in view of the identification of various extrapituitary sources for GHRH production, as well as the demonstration of a direct action of GHRH on several tissues other than the pituitary. Non-pituitary GHRH has a wide spectrum of activity, exemplified by its ability to modulate cell proliferation, especially in malignant tissues, to regulate differentiation of some cell types, and to promote healing of skin wounds. These findings extend the role of GHRH and its analogs beyond its accepted regulation of somatotropic activity and indicate new possibilities for therapeutic intervention.

Protocol for the examination of specimens from patients with primary pituitary tumors

In an effort to improve the diagnosis of pituitary tumors, we propose a synoptic approach to pituitary pathology reporting that will provide clear information to endocrinologists, neurosurgeons, neuropathologists, and surgical pathologists to advance the diagnosis and classification of pituitary adenomas.

Biochemical polymorphism of the growth hormone system proteins and its manifestations in human prostate cells

The basic mechanisms are considered that are responsible for producing biochemical polymorphism of human proteins realized at three basic levels: the structures of genome and genes; the transcription and maturation of transcripts; the postsynthetic formation of functionally active protein products of gene expression. The data on biochemical polymorphism of growth hormone (GH) and some other proteins that are directly or indirectly necessary for its functioning and support this polymorphism by polylocus, polyallelism, alternative splicing, and various postsynthetic modifications are analyzed. The role of polymorphic proteins of the GH system is discussed in formation of a variety of oligomeric molecular structures of this system (multicomponent transport complexes, receptors, and endocellular protein ensembles involved in the regulation of gene expression). It is emphasized that such structural polymorphism significantly influences the biological effects in various parts of the GH system during physiological processes and in tumors, in particular in prostate cancer.

Pancreatic endocrine tumors

Pancreatic endocrine tumors have been steadily growing in incidence and prevalence during the last two decades, showing an incidence of 4-5/1,000,000 population. They represent a heterogeneous group with very varying tumor biology and prognosis. About half of the patients present clinical symptoms and syndromes related to substances released from the tumors (Zollinger-Ellison syndrome, insulinoma, glucagonoma, etc) and the other half are so-called nonfunctioning tumors mainly presenting with symptoms such as obstruction, jaundice, bleeding, and abdominal mass. Ten percent to 15% of the pancreatic endocrine tumors are part of an inherited syndrome such as multiple endocrine neoplasia type 1 (MEN-1), von Hippel-Lindau (VHL), neurofibromatosis, or tuberousclerosis. The diagnosis is based on histopathology demonstrating neuroendocrine features such as positive staining for chromogranin A and specific hormones such as gastrin, proinsulin, and glucagon. Moreover, the biochemical diagnosis includes measurement of chromogranins A and B or specific hormones such as gastrin, insulin, glucagon, and vasoactive intestinal polypeptide (VIP) in the circulation. In addition to standard localization procedures, radiology (computed tomography [CT] scan, magnetic resonance imaging [MRI], ultrasound [US]), somatostatin receptor scintigraphy, and most recently positron emission tomography with specific isotopes such as (11)C-5 hydroxytryptamin ((11)C-5-HTP), fluorodopa and (68)Ga-1,4,7,10-tetra-azacyclododecane-N,N',N″,N‴-tetra-acetic acid (DOTA)-octreotate are performed. Surgery is still one of the cornerstones in the management of pancreatic endocrine tumors, but curative surgery is rarely obtained in most cases because of metastatic disease. Debulking and other cytoreductive procedures might facilitate systemic treatment. Cytotoxic drugs, biological agents, such as somatostatin analogs, alpha interferons, mammalian target of rapamycin (mTOR) inhibitors and tyrosine kinase inhibitors are routinely used. Tumor-targeted radioactive treatment is available in many centres in Europe and is effective in patients with tumors that express high content of somatostatin receptors type 2 and 5. In the future, treatment will be based on tumor biology and molecular genetics with the aim of so-called personalized medicine.

Craniopharyngioma in a patient with acromegaly due to a pituitary macroadenoma

We present the first reported case of a craniopharyngioma as a second primary tumor in a patient with acromegaly due to a growth hormone (GH)-secreting pituitary adenoma. The patient was lost for follow-up for 18 years after trans-sphenoidal pituitary surgery for a GH-secreting pituitary adenoma. She presented with headaches and decreased visual acuity, and showed unsuppressed GH in an oral glucose load test with high IGF-1 levels. Brain MRI showed a suprasellar cystic mass and the patient underwent surgery for cyst drainage resulting in postoperative improvement in her vision. Biopsy of the mass confirmed the diagnosis of a craniopharyngioma. We stress the need for close follow-up of patients with acromegaly with adequate control of GH and IGF-1 levels.

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.

Acromegaly pathogenesis and treatment

Dysregulated growth hormone (GH) hypersecretion is usually caused by a GH-secreting pituitary adenoma and leads to acromegaly - a disorder of disproportionate skeletal, tissue, and organ growth. High GH and IGF1 levels lead to comorbidities including arthritis, facial changes, prognathism, and glucose intolerance. If the condition is untreated, enhanced mortality due to cardiovascular, cerebrovascular, and pulmonary dysfunction is associated with a 30% decrease in life span. This Review discusses acromegaly pathogenesis and management options. The latter include surgery, radiation, and use of novel medications. Somatostatin receptor (SSTR) ligands inhibit GH release, control tumor growth, and attenuate peripheral GH action, while GH receptor antagonists block GH action and effectively lower IGF1 levels. Novel peptides, including SSTR ligands, exhibiting polyreceptor subtype affinities and chimeric dopaminergic-somatostatinergic properties are currently in clinical trials. Effective control of GH and IGF1 hypersecretion and ablation or stabilization of the pituitary tumor mass lead to improved comorbidities and lowering of mortality rates for this hormonal disorder.

The pathogenesis of pituitary tumors

Recently there has been significant progress in our understanding of pituitary development, physiology, and pathology. New information has helped to clarify the classification of pituitary tumors. Epidemiologic analyses have identified a much higher incidence of pituitary tumors than previously thought. We review the pathogenetic factors that have been implicated in pituitary tumorigenesis and the application of novel targeted therapies that underscore the increasingly important role of the pathologist in determining accurate diagnoses and facilitating appropriate treatment of patients with these disorders.

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

Acromegaly is caused by growth hormone hypersecretion, mostly from a pituitary adenoma, driving insulin-like growth factor 1 overproduction. Manifestations include skeletal and soft tissue growth and deformities; and cardiac, respiratory, neuromuscular, endocrine, and metabolic complications. Increased morbidity and mortality require early and tight disease control. Surgery is the treatment of choice for microadenomas and well-defined intrasellar macroadenomas. Complete resection of large and invasive macroadenomas rarely is achieved; hence, their low rate of disease remission. Pharmacologic treatments, including long-acting somatostatin analogs, dopamine agonists, and growth hormone receptor antagonists, have assumed more importance in achieving biochemical and symptomatic disease control.

Combined gangliocytoma and prolactinoma of the pituitary gland

Gangliocytomas of the pituitary gland are rare lesions that often occur in combination with pituitary adenomas, which are frequently associated with the hypersecretion of pituitary hormones, particularly growth hormones. We report a case of combined gangliocytoma and prolactinoma of the pituitary gland. A 49-year-old male presented with vertigo. Radiological examination revealed an intrasellar tumor with a suprasellar extension, which was removed via the trans-sphenoidal approach. Histologically, the tumor was composed of adenoma cells, mature ganglion cells and cells with features intermediate between those of adenoma cells and ganglion cells (intermediate cells). Immunohistochemical analysis revealed the ganglion cells and intermediate cells as well as adenoma cells to be positive for prolactin. No growth hormone-positive tumor cells were observed. The ganglion cells were positive for synaptophysin and neurofilament. The findings in this case are discussed in relation to hypotheses proposed for histogenesis, and the presence of intermediate cells supports three hypotheses. The first is that adenoma cells transform into ganglion cells, and the second is that both components originate from the embryonal pituitary cell rests, showing intermediate features between ganglion cells and adenoma cells. The last is that their common origin may be the same stem/progenitor cells in normal adult pituitaries.

Senescence mediates pituitary hypoplasia and restrains pituitary tumor growth

Understanding factors subserving pituitary cell proliferation enables understanding mechanisms underlying uniquely benign pituitary tumors. Pituitary tumor-transforming gene (Pttg) deletion results in pituitary hypoplasia, low pituitary cell proliferation rates, and rescue of pituitary tumor development in Rb(+/-) mice. Pttg(-/-) pituitary glands exhibit ARF/p53/p21-dependent senescence pathway activation evidenced by up-regulated p19, cyclin D1, and Bcl-2 protein levels and p53 stabilization. High pituitary p21 levels in the absence of PTTG were associated with suppressed cyclin-dependent kinase 2 activity, Rb phosphorylation, and cyclin A expression, all required for cell cycle progression. Although senescence-associated beta-galactosidase was enhanced in Pttg-deficient pituitary glands, telomere lengths were increased. DNA damage signaling pathways were activated and aneuploidy was evident in the Pttg-deficient pituitary, triggering senescence-associated genes. To confirm the p21 dependency of decreased proliferation and senescence in the Pttg-null pituitary, mouse embryonic fibroblast (MEF) colony formation was tested in wild-type, Pttg(-/-), Rb(+/-), Rb(+/-)Pttg(-/-), and Rb(+/-)Pttg(-/-)p21(-/-) cells. Rb(+/-)Pttg(-/-) MEFs, unlike Rb(+/-) cells, failed to produce colonies and exhibited high levels of senescence. p21 deletion from Rb(+/-)Pttg(-/-) MEFs enhanced anchorage-independent cell growth, accompanied by a marked decrease in senescence. As cell proliferation assessed by bromodeoxyuridine incorporation was higher in Rb(+/-)Pttg(-/-)p21(-/-) relative to Rb(+/-)Pttg(-/-) pituitary glands, p21-dependent senescence provoked by Pttg deletion may underlie pituitary hypoplasia and decreased tumor development in Rb(+/-)Pttg(-/-) mice.

Factors regulating growth hormone secretion in humans

Growth hormone (GH) secretion is pulsatile in nature in all species. The periodic pattern of GH release plays an important role in transmitting the GH message in a tissue-specific manner. The question of what regulates the pulsatile GH secretion pattern is an issue of not only theoretical interest but of considerable practical importance for designing different GH therapies for a variety of human diseases. This article provides a brief introductory overview of the different regulators of GH secretion and concentrates primarily on human studies.

Discovery of growth hormone-releasing hormones and receptors in nonmammalian vertebrates

In mammals, growth hormone-releasing hormone (GHRH) is the most important neuroendocrine factor that stimulates the release of growth hormone (GH) from the anterior pituitary. In nonmammalian vertebrates, however, the previously named GHRH-like peptides were unable to demonstrate robust GH-releasing activities. In this article, we provide evidence that these GHRH-like peptides are homologues of mammalian PACAP-related peptides (PRP). Instead, GHRH peptides encoded in cDNAs isolated from goldfish, zebrafish, and African clawed frog were identified. Moreover, receptors specific for these GHRHs were characterized from goldfish and zebrafish. These GHRHs and GHRH receptors (GHRH-Rs) are phylogenetically and structurally more similar to their mammalian counterparts than the previously named GHRH-like peptides and GHRH-like receptors. Information regarding their chromosomal locations and organization of neighboring genes confirmed that they share the same origins as the mammalian genes. Functionally, the goldfish GHRH dose-dependently activates cAMP production in receptor-transfected CHO cells as well as GH release from goldfish pituitary cells. Tissue distribution studies showed that the goldfish GHRH is expressed almost exclusively in the brain, whereas the goldfish GHRH-R is actively expressed in brain and pituitary. Taken together, these results provide evidence for a previously uncharacterized GHRH-GHRH-R axis in nonmammalian vertebrates. Based on these data, a comprehensive evolutionary scheme for GHRH, PRP-PACAP, and PHI-VIP genes in relation to three rounds of genome duplication early on in vertebrate evolution is proposed. These GHRHs, also found in flounder, Fugu, medaka, stickleback, Tetraodon, and rainbow trout, provide research directions regarding the neuroendocrine control of growth in vertebrates.

Growth hormone measurements in the diagnosis and monitoring of acromegaly

Before the availability of immunoassays for IGF-I, growth hormone (GH) measurement was the sole method used in the biochemical assessment of acromegaly. IGF-I has since been established as the most reliable biochemical indicator of acromegaly. The last 25 years has seen important advances in the understanding of the neuroregulation and in the characterization of GH secretion in acromegaly. The availability of supersensitive GH has changed many aspects of the interpretation of GH-value in the management of acromegaly. Hypersecretion and abnormal neuroregulation characterize GH secretion in acromegaly. GH can be measured in many ways: as a single random sample, as multiple samples, either spontaneously or as an integral part of a dynamic test. These approaches give useful information on diagnosis, therapy, and prognosis. There is a place for measuring GH in the management of acromegaly although it complements that of IGF-I.

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.