Asymptomatic children with multiple endocrine neoplasia type 1 mutations may harbor nonfunctioning pancreatic neuroendocrine tumors

European Neuroendocrine Tumour Society (ENETS) 2023 guidance paper for nonfunctioning pancreatic neuroendocrine tumours

This ENETS guidance paper for well-differentiated nonfunctioning pancreatic neuroendocrine tumours (NF-Pan-NET) has been developed by a multidisciplinary working group, and provides up-to-date and practical advice on the management of these tumours. Using the extensive experience of centres treating patients with NF-Pan-NEN, the authors of this guidance paper discuss 10 troublesome questions in everyday clinical practice. Our many years of experience in this field are still being verified in the light of the results of new clinical, which set new ways of proceeding in NEN. The treatment of NF-Pan-NEN still requires a decision of a multidisciplinary team of specialists in the field of neuroendocrine neoplasms.

Molecular and Clinical Spectrum of Primary Hyperparathyroidism

Recent data suggest an increase in the overall incidence of parathyroid disorders, with primary hyperparathyroidism (PHPT) being the most prevalent parathyroid disorder. PHPT is associated with morbidities (fractures, kidney stones, chronic kidney disease) and increased risk of death. The symptoms of PHPT can be nonspecific, potentially delaying the diagnosis. Approximately 15% of patients with PHPT have an underlying heritable form of PHPT that may be associated with extraparathyroidal manifestations, requiring active surveillance for these manifestations as seen in multiple endocrine neoplasia type 1 and 2A. Genetic testing for heritable forms should be offered to patients with multiglandular disease, recurrent PHPT, young onset PHPT (age ≤40 years), and those with a family history of parathyroid tumors. However, the underlying genetic cause for the majority of patients with heritable forms of PHPT remains unknown. Distinction between sporadic and heritable forms of PHPT is useful in surgical planning for parathyroidectomy and has implications for the family. The genes currently known to be associated with heritable forms of PHPT account for approximately half of sporadic parathyroid tumors. But the genetic cause in approximately half of the sporadic parathyroid tumors remains unknown. Furthermore, there is no systemic therapy for parathyroid carcinoma, a rare but potentially fatal cause of PHPT. Improved understanding of the molecular characteristics of parathyroid tumors will allow us to identify biomarkers for diagnosis and novel targets for therapy.

Multiple Endocrine Neoplasia in Childhood: An Update on Diagnosis, Screening, Management and Treatment

Multiple endocrine neoplasia (MEN) is a group of heterogenous syndromes characterized by the occurrence of two or more endocrine gland tumors in a patient or related individuals in the same family. They are inherited in an autosomal dominant fashion and are highly penetrant. There are three types of MEN syndromes: MEN type 1 (MEN1), MEN type 2 (MEN2), and MEN type 4 (MEN4). MEN2 is further divided into MEN2A, MEN2B (formerly known MEN3), and familial medullary thyroid carcinoma (FMTC). Although MEN syndromes are rare, it is crucial to identify individuals at risk for potentially life-threatening neoplasias. This review article provides an update on each MEN syndrome, its genetics, diagnosis, and management in children.

Initiating Pancreatic Neuroendocrine Tumor (pNET) Screening in Young MEN1 Patients: Results From the DutchMEN Study Group

CONTEXT

Nonfunctioning pancreatic neuroendocrine tumors (NF-pNETs) are highly prevalent and constitute an important cause of mortality in patients with multiple endocrine neoplasia type 1 (MEN1). Still, the optimal age to initiate screening for pNETs is under debate.

OBJECTIVE

The aim of this work is to assess the age of occurrence of clinically relevant NF-pNETs in young MEN1 patients.

METHODS

Pancreatic imaging data of MEN1 patients were retrieved from the DutchMEN Study Group database. Interval-censored survival methods were used to describe age-related penetrance, compare survival curves, and develop a parametric model for estimating the risk of having clinically relevant NF-pNET at various ages. The primary objective was to assess age at occurrence of clinically relevant NF-pNET (size ≥ 20 mm or rapid growth); secondary objectives were the age at occurrence of NF-pNET of any size and pNET-associated metastasized disease.

RESULTS

Five of 350 patients developed clinically relevant NF-pNETs before age 18 years, 2 of whom subsequently developed lymph node metastases. No differences in clinically relevant NF-pNET-free survival were found for sex, time frame, and type of MEN1 diagnosis or genotype. The estimated ages (median, 95% CI) at a 1%, 2.5%, and 5% risk of having developed a clinically relevant tumor are 9.5 (6.5-12.7), 13.5 (10.2-16.9), and 17.8 years (14.3-21.4), respectively.

CONCLUSION

Analyses from this population-based cohort indicate that start of surveillance for NF-pNETs with pancreatic imaging at age 13 to 14 years is justified. The psychological and medical burden of screening at a young age should be considered.

Multiple endocrine neoplasia type 1 in children and adolescents: Clinical features and treatment outcomes

BACKGROUND

Clinical manifestations and treatment outcomes in children and adolescents with multiple endocrine neoplasia type 1 are not well characterized.

METHODS

We conducted a retrospective cohort study of 80 patients with multiple endocrine neoplasia type 1 who commenced tumor surveillance at ≤18 years of age.

RESULTS

Fifty-six patients (70%) developed an endocrine tumor by age ≤18 years (median age = 14 years, range = 6-18 years). Primary hyperparathyroidism occurred in >80% of patients, with >70% undergoing parathyroidectomy, in which less-than-subtotal (<3-gland) resection resulted in decreased disease-free outcomes versus subtotal (3-3.5-gland) or total (4-gland) parathyroidectomy (median 27 months versus not reached; P = .005). Pancreaticoduodenal neuroendocrine tumors developed in ∼35% of patients, of whom >70% had nonfunctioning tumors, >35% had insulinomas, and <5% had gastrinomas, with ∼15% having metastases and >55% undergoing surgery. Pituitary tumors developed in >30% of patients, and ∼35% were macroprolactinomas. Tumor occurrence in male patients and female patients was not significantly different. Genetic analyses revealed 38 germline MEN1 mutations, of which 3 were novel.

CONCLUSION

Seventy percent of children aged ≤18 years with multiple endocrine neoplasia type 1 develop endocrine tumors, which include parathyroid tumors for which less-than-subtotal parathyroidectomy should be avoided; pancreaticoduodenal neuroendocrine tumors that may metastasize; and pituitary macroprolactinomas.

Clinical aspects of multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN1) is a rare syndrome characterized by the co-occurrence of primary hyperparathyroidism, duodenopancreatic neuroendocrine tumours (NETs) and/or pituitary adenomas. MEN1 can predispose patients to other endocrine and non-endocrine tumours, such as cutaneous tumours, central nervous system tumours and breast cancer. Endocrine tumours in patients with MEN1 differ from sporadic tumours in that they have a younger age at onset, present as multiple tumours in the same organ and have a different clinical course. Therefore, patients with overt MEN1 and those who carry a MEN1 mutation should be offered tailored biochemical and imaging screening to detect tumours and evaluate their progression over time. Fortunately, over the past 10 years, knowledge about the clinical phenotype of these tumours has markedly progressed, thanks to the implementation of national registries, particularly in France and the Netherlands. This Review provides an update on the clinical management of MEN1-related tumours. Epidemiology, the clinical picture, diagnostic work-up and the main lines of treatment for MEN1-related tumours are summarized. Controversial therapeutic aspects and issues that still need to be addressed are also discussed. Moreover, special attention is given to MEN1 manifestations in children and adolescents.

Familial Hyperparathyroidism

Regulation of the serum calcium level in humans is achieved by the endocrine action of parathyroid glands working in concert with vitamin D and a set of critical target cells and tissues including osteoblasts, osteoclasts, the renal tubules, and the small intestine. The parathyroid glands, small highly vascularized endocrine organs located behind the thyroid gland, secrete parathyroid hormone (PTH) into the systemic circulation as is needed to keep the serum free calcium concentration within a tight physiologic range. Primary hyperparathyroidism (HPT), a disorder of mineral metabolism usually associated with abnormally elevated serum calcium, results from the uncontrolled release of PTH from one or several abnormal parathyroid glands. Although in the vast majority of cases HPT is a sporadic disease, it can also present as a manifestation of a familial syndrome. Many benign and malignant sporadic parathyroid neoplasms are caused by loss-of-function mutations in tumor suppressor genes that were initially identified by the study of genomic DNA from patients who developed HPT as a manifestation of an inherited syndrome. Somatic and inherited mutations in certain proto-oncogenes can also result in the development of parathyroid tumors. The clinical and genetic investigation of familial HPT in kindreds found to lack germline variants in the already known HPT-predisposition genes represents a promising future direction for the discovery of novel genes relevant to parathyroid tumor development.

Unusual Combination of MEN-1 and the Contiguous Gene Deletion Syndrome of CAH and Ehlers-Danlos Syndrome (CAH-X)

The contiguous gene deletion syndrome of congenital adrenal hyperplasia and Ehlers-Danlos syndrome, named CAH-X, is a rare entity that occurs because of a deletion of a chromosomal area containing 2 neighboring genes, TNXB and CYP21A. Here, we describe a patient from a consanguineous family in which coincidentally MEN-1 syndrome is associated with CAH-X, causing particular challenges explaining the phenotypic features of the patient. A 33-year-old man with salt-wasting congenital adrenal hyperplasia and classic-like Ehlers-Danlos syndrome presented with an adrenal crisis with a history of recurrent hypoglycemia, abdominal pain, and vomiting. He was found to have primary hyperparathyroidism, hyperprolactinemia, and pancreatic neuroendocrine tumors, as well as primary hypogonadism, large adrenal myelolipomas, and low bone mineral density. A bladder diverticulum was incidentally found. Genetic analysis revealed a heterozygous previously well-described MEN1 mutation (c.784-9G > A), a homozygous complete deletion of CYP21A2 (c.1-?_1488+? del), as well as a large deletion of the neighboring TNXB gene (c.11381-?_11524+?). The deletion includes the complete CYP21A2 gene and exons 35 through 44 of the TNXB gene. CGH array found 12% homozygosity over the whole genome. This rare case illustrates a complex clinical scenario with some initial diagnostic challenges.

La néoplasie endocrinienne multiple de type 1 : mise au point après le congrès de l’ENETS 2019

Multiple Endocrine Neoplasia Type 1 (NEM1) is related to mutations of the menin gene. It is an autosomal dominant disease. Its prevalence is about 1/30 000 with a hugh penetrance. There is no genotype-phenotype correlation. This hereditary syndrome is characterized by the presence of tumors of the endocrine system (parathyroid, endocrine pancreas, pituitary and adrenal gland). Other disorders have also been described (bronchial and thymic carcinoid tumor, breast cancer, skin lesions). Management must take into account the specificities of these pathologies in NEM1 compared to sporadic forms (young age at diagnosis, multiple lesions within the same gland, multi-focal disease). © 2019 Published by Elsevier Masson SAS. All rights reserved. Cet article fait partie du numéro supplément Les Must de l'Endocrinologie 2019 réalisé avec le soutien institutionnel de Ipsen-Pharma.

What is the appropriate management of nonfunctioning pancreatic neuroendocrine tumours disclosed on screening in adult patients with multiple endocrine neoplasia type 1?

Multiple endocrine neoplasia type 1 (MEN1) is an inherited tumour syndrome characterised by a predisposition to the development of endocrine tumours of the parathyroid glands, pituitary and pancreas: 30%-80% of patients with MEN1 develop pancreatic neuroendocrine tumours (pNETs), with metastatic tumours and/or their sequelae contributing to increased morbidity and early mortality. The optimal management of nonfunctioning (NF) pNETs in MEN1 remains controversial. Whilst pancreatic resection is widely recommended for tumours >2 cm, for smaller tumours (≤2 cm) a well-established consensus guiding the indications for surgical intervention does not exist. Although total pancreatectomy may be curative for some patients, both short- and long-term complications make this an unsatisfactory option for many patients. For small (<2 cm) MEN1 NF-pNETs, some clinicians advocate surveillance based largely on retrospective data that suggest 50%-80% of these lesions are stable over time and infrequently exhibit accelerated growth rates. It is increasingly recognised, however, that NF-pNETs exhibit unpredictable malignant behaviour that is not determined by tumour size alone, thereby prompting other clinicians to advocate surgery for all MEN1 NF-pNETs, irrespective of size. Such uncertainty poses clinical management challenges with regards to the timing and extent of surgery, which is further hindered by the inability to stratify patients based on predicted tumour behaviour. It is therefore critical that future MEN1 research initiatives include: (a) the discovery of biomarkers that better predict tumour behaviour; (b) the evaluation of medical therapies that may delay, or even prevent, the need for pancreatic surgery; and, ultimately, (c) improvement in the quality of life for individuals with MEN1. Here, based on the published literature, we address the Clinical Question, 'What is the management of NF-pNETs disclosed on screening in adult patients with MEN1?'.

Results of Duodenopancreatic Reoperations in Multiple Endocrine Neoplasia Type 1

BACKGROUND

To evaluate the outcome of duodenopancreatic reoperations in patients with multiple endocrine neoplasia type 1 (MEN1).

METHODS

MEN1 patients who underwent reoperations for duodenopancreatic neuroendocrine neoplasms (dpNENs) were retrieved from a prospective database and retrospectively analyzed.

RESULTS

Twelve of 101 MEN1 patients underwent up to three reoperations, resulting in a total of 18 reoperations for dpNEN recurrence. Patients initially underwent either formal pancreatic resections (n = 7), enucleations (n = 3), or duodenotomy with lymphadenectomy for either NF-pNEN (seven patients), Zollinger-Ellison syndrome (ZES, three patients), organic hyperinsulinism (one patient) or VIPoma (one patient). Six patients had malignant dpNENs with lymph node (n = 5) and/or liver metastases (n = 2). The indication of reoperations was NF-pNEN (five patients), ZES (five patients), organic hyperinsulinism (one patient), and recurrent VIPoma (one patient). Median time to first reoperation was 67.5 (range 6-251) months. Five patients required a second duodenopancreatic reoperation for 60-384 months after initial surgery, and one patient underwent a third reoperation after 249 months. The rate of complications (Clavien-Dindo ≥3) was 28%. Four patients required completion pancreatectomy. Six patients developed pancreoprivic diabetes. After a median follow-up of 18 (6-34) years after initial surgery, ten of 12 patients are alive, one died of metastatic pancreatic VIPoma, and one died of metastatic thymic NEN.

CONCLUSION

Reoperations are frequently necessary for dpNEN in MEN1 patients, but are not associated with an increased perioperative morbidity in specialized centers. Organ-sparing resections should be preferred as initial duodenopancreatic procedures to maintain pancreatic function and avoid completion pancreatectomy.

Proposition of adjustments to the ACMG-AMP framework for the interpretation of MEN1 missense variants

In 2015, the ACMG-AMP guidelines provided a general procedure for the objective and reproducible classification of genomic variants. While the benefits of this framework are of major importance, its adaptation for locus-specific use is needed. Multiple Endocrine Neoplasia type 1 (MEN1) occurs due to inactivating mutations in the tumour suppressor gene MEN1, including 20% of missense variants. The classification of these variants may be extremely challenging. Here, we compared the interpretation of the 122 MEN1 missense variants, identified in the French population over the past 15 years by the TENGEN network (French oncogenetics network of neuroendocrine tumors) versus by using the ACMG-AMP guidelines, and analyzed the causes of discordance. A total of 59.8% of missense variants were termed as (likely)-pathogenic variants by TENGEN versus only 28.7% using ACMG-AMP guidelines. Actually, 53.4% (39/73) of TENGEN (likely)-pathogenic variants were declassified in variant of uncertain significance (VUS) by using ACMG-AMP guidelines, thereby affecting the clinical management of patients and their families. Twenty of these ACMG-AMP VUS were found in patients with a clinically authentic MEN1 disease. Here, TENGEN proposes adjustments to the ACMG-AMP framework for the interpretation of MEN1 missense variants. These propositions merge both the classification systems, and are particularly interesting, as MEN1 is included in the ACMG secondary findings list for reporting in clinical genomic sequencing.

Multiple Endocrine Neoplasia Type 1 (MEN1): An Update and the Significance of Early Genetic and Clinical Diagnosis

Multiple endocrine neoplasia type 1 (MEN1) is a rare hereditary tumor syndrome inherited in an autosomal dominant manner and characterized by a predisposition to a multitude of endocrine neoplasms primarily of parathyroid, enteropancreatic, and anterior pituitary origin, as well as nonendocrine neoplasms. Other endocrine tumors in MEN1 include foregut carcinoid tumors, adrenocortical tumors, and rarely pheochromocytoma. Nonendocrine manifestations include meningiomas and ependymomas, lipomas, angiofibromas, collagenomas, and leiomyomas. MEN1 is caused by inactivating mutations of the tumor suppressor gene MEN1 which encodes the protein menin. This syndrome can affect all age groups, with 17% of patients developing MEN1-associated tumors before 21 years of age. Despite advances in the diagnosis and treatment of MEN1-associated tumors, patients with MEN1 continue to have decreased life expectancy primarily due to malignant neuroendocrine tumors. The most recent clinical practice guidelines for MEN1, published in 2012, highlight the need for early genetic and clinical diagnosis of MEN1 and recommend an intensive surveillance approach for both patients with this syndrome and asymptomatic carriers starting at the age of 5 years with the goal of timely detection and management of MEN1-associated neoplasms and ultimately decreased disease-specific morbidity and mortality. Unfortunately, there is no clear genotype-phenotype correlation and individual mutation-dependent surveillance is not possible currently.

Diagnosing Nonfunctional Pancreatic NETs in MEN1: The Evidence Base

In multiple endocrine neoplasia type 1 (MEN1), nonfunctional pancreatic neuroendocrine tumors (NF-pNETs) are the most frequently diagnosed NETs and a leading cause of MEN1-related death. The high prevalence and malignant potential of NF-pNETs outline the need for an evidence-based screening program, as early diagnosis and timely intervention could reduce morbidity and mortality. Controversies exist regarding the value of several diagnostic tests. This systematic review aims to evaluate current literature and amplify an up-to-date evidence-based approach to NF-pNET diagnosis in MEN1. Three databases were systematically searched on the diagnostic value of biomarkers and imaging modalities. Twenty-seven studies were included and critically appraised (modified Quality Assessment of Diagnostic Accuracy Studies). Another 12 studies, providing data on age-related penetrance and tumor growth, were included to assess the optimal frequency and timing of screening. Based on current literature, biomarkers should no longer play a role in the diagnostic process for NF-pNETs, as accuracies are too low. Studies evaluating the diagnostic value of imaging modalities are heterogeneous with varying risks of bias. For the detection of NF-pNETs, endoscopic ultrasound (EUS) has the highest sensitivity. A combined strategy of EUS and MRI seems to be the most useful. Gallium 68 octreotate-DOTA positron emission tomography-CT could be added if NF-pNETs are diagnosed to identify metastasis. Reported growth rates were generally low, and two distinct phenotypes were observed. Surveillance programs should focus on and be adapted to the presence of substantial growth in NF-pNETs. The optimal age to start screening must yet be determined, as insufficient evidence for an evidence-based recommendation was available.

Current and emerging therapies for PNETs in patients with or without MEN1

Pancreatic neuroendocrine tumours (PNETs) might occur as a non-familial isolated endocrinopathy or as part of a complex hereditary syndrome, such as multiple endocrine neoplasia type 1 (MEN1). MEN1 is an autosomal dominant disorder characterized by the combined occurrence of PNETs with tumours of the parathyroids and anterior pituitary. Treatments for primary PNETs include surgery. Treatments for non-resectable PNETs and metastases include biotherapy (for example, somatostatin analogues, inhibitors of receptors and monoclonal antibodies), chemotherapy and radiological therapy. All these treatments are effective for PNETs in patients without MEN1; however, there is a scarcity of clinical trials reporting the efficacy of the same treatments of PNETs in patients with MEN1. Treatment of PNETs in patients with MEN1 is challenging owing to the concomitant development of other tumours, which might have metastasized. In recent years, preclinical studies have identified potential new therapeutic targets for treating MEN1-associated neuroendocrine tumours (including PNETs), and these include epigenetic modification, the β-catenin-wingless (WNT) pathway, Hedgehog signalling, somatostatin receptors and MEN1 gene replacement therapy. This Review discusses these advances.

Is Routine Screening of Young Asymptomatic MEN1 Patients Necessary?

BACKGROUND

Recent clinical practice guidelines recommend that routine screening of MEN1 mutation carriers should start at the age of 5 years. The occurrence of clinically relevant MEN1 organ manifestations in children (≤18 years) was evaluated.

METHODS

Two prospective collected databases of MEN1 patients (n = 166) who underwent annual screening were retrospectively analyzed for organ manifestations in MEN1 patients ≤18 years. The follow-up was based on the most recent screening examination until December 2015.

RESULTS

Twenty [11 females, 9 males, (12%)] of 166 MEN1 patients were diagnosed with at least one organ manifestation at age ≤18 years. The most frequent manifestation was mild asymptomatic pHPT (n = 9, 45%, age range 8-18 years). Eight (40%) young patients had pNENs (three non-functioning pNENs, five insulinomas, age range 9-18 years). All five insulinomas were diagnosed based on hypoglycemic symptoms. The other organ manifestations were asymptomatic pituitary adenomas in six patients (30%, age range 15-18 years) and a bronchial carcinoid in one 15-year-old patient. Only six (30%) patients ≤18 years had clinically relevant organ manifestations.

CONCLUSION

Symptomatic or severe manifestations in MEN1 patients rarely occur below the age of 16 years. With regard to psychological burden and cost-effectiveness, routine screening of asymptomatic MEN1 patients should be postponed at least until the age of 16 years.

MEN1 in children and adolescents: Data from patients of a regional referral center for hereditary endocrine tumors

PURPOSE

To retrospectively evaluate the age of onset of MEN1-associated lesions in a group of affected children and adolescents and to compare the clinical features of our series with the evidence derived from the literature.

METHODS

The study population consisted of 22 Italian children and adolescents (age 6-31 years at the time of the inclusion in this study) all with a clinical and/or a genetic diagnosis of MEN1 performed before the age of 16 who have been followed-up regularly from 1998 to 2016 at the Regional Referral Center for Hereditary Endocrine Tumors. Clinical, biochemical, imaging and genetic data have been collected for each patient.

RESULTS

Ten subjects (45.5%) have not yet presented any clinical/biochemical/radiological manifestation of MEN1 disease, whereas 12 patients (54.5%) developed at least one MEN1-associated endocrine manifestation. The second group of patients was significantly older than the first one. The most frequent manifestation was primary hyperparathyroidism (50%), followed by pituitary tumors (prolactinomas) (31.8%) and nonfunctioning pancreatic neuroendocrine tumors (9%). The earliest cases of primary hyperparathyroidism and prolactinoma were a 12-year-old girl and a 13-year-old boy, respectively.

CONCLUSIONS

MEN1 disease seems to present with different features in children and adolescents from those in adults. Our study confirms the fundamental importance of screening for tumors in young MEN1 patients beginning in early childhood, in order to avoid diagnostic and therapeutic delays.

Synchronous Solid Pseudopapillary Tumor and Insulinoma in an Adolescent MEN1 Patient Presenting with Diagnostic Dilemmas

Multiple endocrine neoplasia (MEN1) is a rare autosomal dominant disorder characterized by primary hyperparathyroidism, enteropancreatic neuroendocrine tumors, and anterior pituitary adenomas. A 16-year-old male presented to the emergency outpatient clinic with tonic convulsions. Physical examination in the postconvulsive period was unremarkable and revealed a muscular, postpubertal adolescent. Biochemical tests at admission were consistent with hyperinsulinemic hypoglycemia and remarkable for elevated levels of liver transaminases and creatine kinase. Work-up for a potential inborn error of metabolism and Doppler ultrasound for congenital portal-hepatic shunt were negative. When the patient was questioned, he reported using the anabolic steroid stanozolol to strengthen his muscles. His enzyme levels normalized after cessation of stanozolol. Hypoglycemia did not recur on diazoxide therapy. Magnetic resonance imaging showed two discrete lesions in the pancreas. Distal pancreatectomy revealed two masses 1.1 and 1.4 cm in diameter: a solid pseudopapillary tumor and an insulinoma. The patient also had asymptomatic primary hyperparathyroidism. DNA sequence analysis of the MEN1 gene in the index patient and his father and brother revealed a previously reported "pW183S" heterozygous mutation. This case further adds to the "pancreatic tumor" phenotype of MEN1 with the presence of a solid pseudopapillary tumor. This case report also confirms the need to meticulously question drug abuse in adolescents presenting to clinics with diagnostic challenges.

Hypercalcemic Disorders in Children

Hypercalcemia is defined as a serum calcium concentration that is greater than two standard deviations above the normal mean, which in children may vary with age and sex, reflecting changes in the normal physiology at each developmental stage. Hypercalcemic disorders in children may present with hypotonia, poor feeding, vomiting, constipation, abdominal pain, lethargy, polyuria, dehydration, failure to thrive, and seizures. In severe cases renal failure, pancreatitis and reduced consciousness may also occur and older children and adolescents may present with psychiatric symptoms. The causes of hypercalcemia in children can be classified as parathyroid hormone (PTH)-dependent or PTH-independent, and may be congenital or acquired. PTH-independent hypercalcemia, ie, hypercalcemia associated with a suppressed PTH, is commoner in children than PTH-dependent hypercalcemia. Acquired causes of PTH-independent hypercalcemia in children include hypervitaminosis; granulomatous disorders, and endocrinopathies. Congenital syndromes associated with PTH-independent hypercalcemia include idiopathic infantile hypercalcemia (IIH), William's syndrome, and inborn errors of metabolism. PTH-dependent hypercalcemia is usually caused by parathyroid tumors, which may give rise to primary hyperparathyroidism (PHPT) or tertiary hyperparathyroidism, which usually arises in association with chronic renal failure and in the treatment of hypophosphatemic rickets. Acquired causes of PTH-dependent hypercalcemia in neonates include maternal hypocalcemia and extracorporeal membrane oxygenation. PHPT usually occurs as an isolated nonsyndromic and nonhereditary endocrinopathy, but may also occur as a hereditary hypercalcemic disorder such as familial hypocalciuric hypercalcemia, neonatal severe primary hyperparathyroidism, and familial isolated primary hyperparathyroidism, and less commonly, as part of inherited complex syndromic disorders such as multiple endocrine neoplasia (MEN). Advances in identifying the genetic causes have resulted in increased understanding of the underlying biological pathways and improvements in diagnosis. The management of symptomatic hypercalcemia includes interventions such as fluids, antiresorptive medications, and parathyroid surgery. This article presents a clinical, biochemical, and genetic approach to investigating the causes of pediatric hypercalcemia. © 2017 American Society for Bone and Mineral Research.

The future: medical advances in MEN1 therapeutic approaches and management strategies

Multiple endocrine neoplasia type 1 is a rare autosomal inherited disorder associated with a high risk for patients to simultaneously develop tumors of the parathyroid glands, duodenopancreatic neuroendocrine tumors and tumors of the anterior pituitary gland. Early identification of MEN1 in patients enables presymptomatic screening of manifestations, which makes timely interventions possible with the intention to prevent morbidity and mortality. Causes of death nowadays have shifted toward local or metastatic progression of malignant neuroendocrine tumors. In early cohorts, complications like peptic ulcers in gastrinoma, renal failure in hyperparathyroidism, hypoglycemia and acute hypercalcemia were the primary causes of early mortality. Improved medical treatments of these complications led to a significantly improved life expectancy. The MEN1 landscape is still evolving, considering the finding of breast cancer as a new MEN1-related manifestation and ongoing publications on follow-up and medical care for patients with MEN1. This review aims at summarizing the most recent insights into the follow-up and medical care for patients with MEN1 and identifying the gaps for future research.

Late onset asymptomatic pancreatic neuroendocrine tumor - A case report on the phenotypic expansion for MEN1

Background

Multiple endocrine neoplasia type 1 (MEN1) is a hereditary cancer syndrome associated with several endocrine as well as non-endocrine tumors and is caused by mutations in the MEN1 gene. Primary hyperparathyroidism affects the majority of MEN1 individuals by age 50 years. Additionally, MEN1 mutations trigger familial isolated hyperparathyroidism. We describe a seemingly unaffected 76-year-old female who presented to our Genetics Clinic with a family history of primary hyperparathyroidism and the identification of a pathogenic MEN1 variant.

Case Presentation

The patient was a 76 year-old woman who appeared to be unaffected. She had a family history of a known MEN1 pathogenic variant. Molecular testing for the known MEN1 mutation c.1A > G, as well as, biochemical testing, MRI of the brain and abdomen were all performed using standard methods. Molecular testing revealed our patient possessed the MEN1 pathogenic variant previously identified in her two offspring. Physical exam revealed red facial papules with onset in her seventies, involving her cheeks, nose and upper lip. Formerly, she was diagnosed with rosacea by a dermatologist and noted no improvement with treatment. Clinically, these lesions appeared to be facial angiofibromas. Brain MRI was normal. However, an MRI of her abdomen revealed a 1.5 cm lesion at the tail of the pancreas with normal adrenal glands. Glucagon was mildly elevated and pancreatic polypeptide was nearly seven times the upper limit of the normal range. The patient underwent spleen sparing distal pancreatectomy and subsequent pathology was consistent with a well-differentiated pancreatic neuroendocrine tumor (pNET).

Conclusions

Age-related penetrance and variable expressivity are well documented in families with MEN1. It is thought that nearly all individuals with MEN1 manifest disease by age 40. We present a case of late-onset MEN1 in the absence of the most common feature, primary hyperparathyroidism, but with the presence of a pNET and cutaneous findings. This family expands the phenotype associated with the c.1A > G pathogenic variant and highlights the importance of providing comprehensive assessment of MEN1 mutation carriers in families that at first blush may appear to have isolated hyperparathyroidism.

Utility of chromogranin A, pancreatic polypeptide, glucagon and gastrin in the diagnosis and follow-up of pancreatic neuroendocrine tumours in multiple endocrine neoplasia type 1 patients

OBJECTIVE

Pancreatic neuroendocrine tumours (PNETs) are the major source of disease-specific mortality in multiple endocrine neoplasia type 1 (MEN1) patients. Chromogranin A (CgA), pancreatic polypeptide (PP), glucagon and gastrin have some diagnostic value in sporadic PNETs, but there is very little evidence for their efficacy in diagnosing PNETs in MEN1 patients.

DESIGN

We performed a retrospective chart review of the existing MEN1 database in our institution.

PATIENTS

One hundred and thirteen patients were eligible for diagnostic value analysis of tumour markers. Patients were excluded if measurement of tumour markers was missing, either 3 months prior to PNET diagnosis (PNET patients) or prior to abdominal imaging (non-PNET patients).

MEASUREMENTS

Clinicopathologic characteristics and of tumour marker measurements were analysed.

RESULTS

Of 293 confirmed MEN1 cases, 55 PNETs and 58 non-PNETs met inclusion criteria. The area under the curve (AUC) for CgA, PP, glucagon and gastrin in MEN1 cases was 59·5%, 64·1%, 77·0% and 75·9%, respectively. The AUC for the combination of CgA, PP and gastrin was 59·6%. PP, but not CgA, glucagon or gastrin was significantly associated with both age and PNET functional status (P = 0·0485 and 0·0188, respectively). No markers were significantly associated with sex, PNET size, tumour number, tumour location, American Joint Committee on Cancer (AJCC) stage, presence of lymph node metastasis, lymphovascular invasion or overall survival. CgA values were not significantly lower following PNET resection than pre-operatively (P = 0·554).

CONCLUSIONS

The value of blood markers for diagnosing PNETs in MEN1 patients is relatively low, even when used in combination.

Pasireotide Therapy of Multiple Endocrine Neoplasia Type 1-Associated Neuroendocrine Tumors in Female Mice Deleted for an Men1 Allele Improves Survival and Reduces Tumor Progression

Pasireotide, a somatostatin analog, is reported to have anti-proliferative effects in neuroendocrine tumors (NETs). We therefore assessed the efficacy of pasireotide for treating pancreatic and pituitary NETs that develop in a mouse model of multiple endocrine neoplasia type 1 (MEN1). Men1(+/-) mice were treated from age 12 mo with 40 mg/kg pasireotide long-acting release formulation, or PBS, intramuscularly monthly for 9 mo. The Men1(+/-) mice had magnetic resonance imaging at 12 and 21 mo, and from 20 mo oral 5-bromo-2-deoxyuridine for 1 mo, to assess tumor development and proliferation, respectively. NETs were collected at age 21 mo, and proliferation and apoptosis assessed by immunohistochemistry and TUNEL assays, respectively. Pasireotide-treated Men1(+/-) mice had increased survival (pasireotide, 80.9% vs PBS, 65.2%; P < .05), with fewer mice developing pancreatic NETs (pasireotide, 86.9% vs PBS, 96.9%; P < .05) and smaller increases in pituitary NET volumes (pre-treated vs post-treated, 0.803 ± 0.058 mm(3) vs 2.872 ± 0.728 mm(3) [pasireotide] compared with 0.844 ± 0.066 mm(3) vs 8.847 ±1.948 mm(3) [PBS]; P < .01). In addition, pasireotide-treated mice had fewer pancreatic NETs compared with PBS-treated mice (2.36 ± 0.25 vs 3.72 ± 0.32, respectively; P < .001), with decreased proliferation in pancreatic NETs (pasireotide, 0.35 ± 0.03% vs PBS, 0.78 ± 0.08%; P < .0001) and pituitary NETs (pasireotide, 0.73 ±0.07% vs PBS, 1.81 ± 0.15%; P < .0001), but increased apoptosis in pancreatic NETs (pasireotide, 0.42 ± 0.05% vs PBS, 0.19 ± 0.03%; P < .001) and pituitary NETs (pasireotide, 14.75 ± 1.58% vs PBS, 2.35 ± 0.44%; P < .001). Thus, pasireotide increased survival and inhibited pancreatic and pituitary NET growth, thereby indicating its potential as an anti-proliferative and pro-apoptotic therapy.

Multiple Endocrine Neoplasia Syndromes: A Comprehensive Imaging Review

MEN1, MEN2, and MEN4 comprise a series of familial disorders involving the simultaneous occurrence of tumors in more than one endocrine organ, collectively known as multiple endocrine neoplasia. Patients with this family of disorders develop tumors of the parathyroid gland, pancreas, pituitary gland, adrenal gland, and thyroid gland, along with miscellaneous neuroendocrine tumors of the respiratory and gastrointestinal tracts. Although some patients undergo early prophylactic surgical management, particularly in the setting of familial medullary thyroid carcinoma, many develop tumors later in life. These tumors are often discovered at imaging for screening purposes. Recognition of the imaging features of the known tumors is important for appropriate patient management.

Multiple Endocrine Neoplasia: A Genetically Diverse Group of Familial Tumor Syndromes

Multiple endocrine neoplasia (MEN) syndrome is a familial cancer syndrome characterized by neuroendocrine tumors. The syndrome encompasses four major subtypes: MEN1, MEN2A, MEN2B, and MEN4. MEN1 is caused by mutations in the MEN1 gene, MEN2A and MEN2B are caused by mutations in RET, and MEN4 is caused by mutations in CDKNB1. All are inherited in an autosomal dominant pattern, but de novo cases do arise. While all subtypes are associated with neuroendocrine tumors, each has characteristic organ involvement. Identifying patients with the syndrome can aid in proper screening and treatment.

Impact of Delay in Diagnosis in Outcomes in MEN1: Results From the Dutch MEN1 Study Group

OBJECTIVE

Identifying a germline mutation in the multiple endocrine neoplasia type 1 (MEN1) gene in an index case has consequences for a whole family. Eligible family members should be offered genetic counseling and MEN1 mutation testing. Subsequently, clinical screening of mutation carriers according to the guidelines should be initiated. We assessed whether there is a lag time from MEN1 diagnosis of the index case to MEN1 diagnosis of family members. In addition, we determined whether this lag time was associated with an increased morbidity and mortality risk.

DESIGN

A cohort study was performed using the Dutch MEN1 database, including >90% of the Dutch MEN1 population >16 years of age (n = 393).

RESULTS

Fifty-eight MEN1 families were identified, of whom 57 were index cases and 247 were non-index cases (n = 304). The median lag time in MEN1 diagnosis of family members was 3.5 (range, 0-30) years. At the time of MEN1 diagnosis, 30 (12.1%) non-index cases had a duodenopancreatic neuroendocrine tumor, of whom 20% had metastases with a mean lag time of 10.9 years, in comparison with 7.1 years without metastases. Twenty-five (10.1%) non-index cases had a pituitary tumor, of whom 80% had a microadenoma and 20% had a macroadenoma, with mean lag times of 7.2 and 10.6 years, respectively. Ninety-five (38.4%) non-index cases had a primary hyperparathyroidism with a mean lag time of 9.5 years in comparison with seven patients without a primary hyperparathyroidism with a mean lag time of 3 years (P = .005). Ten non-index cases died because of a MEN1-related cause that developed during or before the lag time.

CONCLUSION

There is a clinically relevant delay in MEN1 diagnosis in families because of a lag time between the diagnosis of an index case and the rest of the family. More emphasis should be placed on the conduct of proper counseling and genetic testing in all eligible family members.

Imaging in multiple endocrine neoplasia type 1: recent studies show enhanced sensitivities but increased controversies

In multiple endocrine neoplasia type 1 (MEN1) patients, a number of recent studies compare the ability of different, new imaging modalities to existing modalities to localize the important neuroendocrine tumors (NETs) that contribute to their decreased life expectancy (pancreatic NETs [pNETs] and thymic carcinoids). These included the use of ⁶⁸Ga-DOTATOC-PET/CT, endoscopic ultrasound and MRI. The current paper analyzes these results in light of current guidelines and controversies involved in the treatment/management of MEN1 patients. Particular attention is paid to results in these studies with thymic carcinoids and nonfunctional pNETs/gastrinomas, which recent studies show are particularly important in determining long-term survival. These studies show a number of promising imaging results but also raise a number of controversies, which will need to be addressed both in their use initially and for serial studies in these patients.

Controversies in surgery for multiple endocrine neoplasia type 1-associated Zollinger–Ellison syndrome

Zollinger–Ellison syndrome (ZES) is a common manifestation of multiple endocrine neoplasia type 1 (MEN1). At least 90% of MEN1-ZES patients have multiple duodenal gastrinomas, making the duodenum the target organ of ZES. The indication and the timing of surgery in MEN1-ZES is controversial, since there is yet no parameter that indicates an aggressive course of disease and long-term survival is generally good. An imageable, most likely nonfunctioning pancreatic neuroendocrine neoplasm (pNEN) >1–2 cm seems to be a good surrogate parameter to indicate surgery in order to prevent distant metastatic pNEN disease, although some groups indicate surgery at the time of biochemical ZES evidence. The optimal surgical procedure is also controversial. Different strategies encomprise local excision via duodenotomy with or without distal pancreatic resection and regional lymphadenectomy to partial pancreaticoduodenectomy. At present, the timing and type of surgery for MEN1-ZES should be individualized according to patient’s characteristics and preference.

Challenges and controversies in management of pancreatic neuroendocrine tumours in patients with MEN1

Multiple endocrine neoplasia type 1 (MEN1), an autosomal dominant disorder, is characterised by the occurrence of pancreatic neuroendocrine tumours (P-NETs) in association with parathyroid and pituitary tumours. P-NETs, which include gastrinomas, insulinomas, and non-functioning tumours, occur in more than 80% of MEN1 patients and account for 50% of disease-specific deaths. However, there is no consensus about the optimal methods for detecting and treating P-NETs in MEN1 patients, and extrapolations from approaches used in patients with non-familial (sporadic) P-NETs require caution because of differences, such as the younger age of onset, multi-focality of P-NETs, and concomitant presence of other tumours in MEN1 patients. Thus, the early detection of P-NETs by circulating biomarkers and imaging modalities, and their appropriate treatments by surgical approaches and/or radionuclide therapy, chemotherapy, and biotherapy pose challenges and controversies. These challenges and controversies will be reviewed and possible approaches proposed.

Multiple endocrine neoplasia syndromes 1 and 2: manifestations and management in childhood and adolescence

The identification of the genetic causes of the multiple endocrine neoplasia (MEN) syndromes 1 and 2, and associated genotype-phenotype relationships, has revolutionised the clinical care of affected patients. A genetic diagnosis can be made during infancy and careful clinical surveillance, coupled with early intervention, has the potential to improve both morbidity and mortality. These developments have seen the management of patients with MEN move into the arena of paediatric medicine. In this review article, we consider the genetic causes of MEN together with the clinical manifestations and management of these syndromes.

Multiple endocrine neoplasia type 1 (MEN1) and type 4 (MEN4)

Multiple endocrine neoplasia (MEN) is characterized by the occurrence of tumors involving two or more endocrine glands within a single patient. Four major forms of MEN, which are autosomal dominant disorders, are recognized and referred to as: MEN type 1 (MEN1), due to menin mutations; MEN2 (previously MEN2A) due to mutations of a tyrosine kinase receptor encoded by the rearranged during transfection (RET) protoncogene; MEN3 (previously MEN2B) due to RET mutations; and MEN4 due to cyclin-dependent kinase inhibitor (CDNK1B) mutations. Each MEN type is associated with the occurrence of specific tumors. Thus, MEN1 is characterized by the occurrence of parathyroid, pancreatic islet and anterior pituitary tumors; MEN2 is characterized by the occurrence of medullary thyroid carcinoma (MTC) in association with phaeochromocytoma and parathyroid tumors; MEN3 is characterized by the occurrence of MTC and phaeochromocytoma in association with a marfanoid habitus, mucosal neuromas, medullated corneal fibers and intestinal autonomic ganglion dysfunction, leading to megacolon; and MEN4, which is also referred to as MENX, is characterized by the occurrence of parathyroid and anterior pituitary tumors in possible association with tumors of the adrenals, kidneys, and reproductive organs. This review will focus on the clinical and molecular details of the MEN1 and MEN4 syndromes. The gene causing MEN1 is located on chromosome 11q13, and encodes a 610 amino-acid protein, menin, which has functions in cell division, genome stability, and transcription regulation. Menin, which acts as scaffold protein, may increase or decrease gene expression by epigenetic regulation of gene expression via histone methylation. Thus, menin by forming a subunit of the mixed lineage leukemia (MLL) complexes that trimethylate histone H3 at lysine 4 (H3K4), facilitates activation of transcriptional activity in target genes such as cyclin-dependent kinase (CDK) inhibitors; and by interacting with the suppressor of variegation 3-9 homolog family protein (SUV39H1) to mediate H3K methylation, thereby silencing transcriptional activity of target genes. MEN1-associated tumors harbor germline and somatic mutations, consistent with Knudson's two-hit hypothesis. Genetic diagnosis to identify individuals with germline MEN1 mutations has facilitated appropriate targeting of clinical, biochemical and radiological screening for this high risk group of patients for whom earlier implementation of treatments can then be considered. MEN4 is caused by heterozygous mutations of CDNK1B which encodes the 196 amino-acid CDK1 p27Kip1, which is activated by H3K4 methylation.

Multiple endocrine neoplasia (MEN) syndromes

Multiple endocrine neoplasia (MEN) syndromes are characterised by the combined occurrence of two or more endocrine tumours in a patient. These autosomal dominant conditions occur in four types: MEN1 due to inactivating MEN1 mutations; MEN2A and MEN2B (MEN3) due to activating mutations of RET and MEN4 due to inactivating cyclin-dependent kinase inhibitor 1B (CDKN1B) mutations. Each MEN syndrome exhibits different combinations of pancreatic islet, anterior pituitary, parathyroid, medullary thyroid and adrenal tumours. This article provides an overview of the clinical features, treatments and molecular genetics of each endocrine tumour syndrome.

Preoperative multiple endocrine neoplasia type 1 diagnosis improves the surgical outcomes of pediatric patients with primary hyperparathyroidism

BACKGROUND

Primary hyperparathyroidism (PHPT) is uncommon in children. The surgical management of PHPT in children has evolved over the past two decades.

METHODS

A retrospective study of patients who underwent parathyroidectomy for PHPT diagnosed at age < 18 years and managed at a tertiary referral center for endocrine and familial disorders.

RESULTS

Thirty-eight patients met eligibility criteria (1981-2012). Median age at PHPT diagnosis was 15 years. Two-thirds of patients were symptomatic (68%, n=26), most commonly from nephrolithiasis. Twenty-six (68%) patients underwent a standard cervical exploration while 32% underwent a focused unilateral parathyroidectomy. Multiple endocrine neoplasia type 1 (MEN1) was diagnosed preoperatively in 22/26 patients. Patients with a preoperative diagnosis of MEN1 were more likely to undergo a complete initial operation (≥ 3 gland parathyroidectomy with transcervical thymectomy, 13/22, 59% vs. 0/4, 0%; P=0.03) and less likely to have recurrent disease (10/22, 45% vs. 3/4, 75%; P<0.001) during follow up than patients diagnosed postoperatively.

CONCLUSIONS

Children with PHPT should raise suspicion for MEN1. Preoperative MEN1 evaluation helped guide the extent of initial parathyroidectomy and was associated with lower rates of recurrence in sporadic and familial PHPT in pediatric patients. Management should occur at a high volume center with experienced clinicians and genetic counseling services.

Causes of death and prognostic factors in multiple endocrine neoplasia type 1: a prospective study: comparison of 106 MEN1/Zollinger-Ellison syndrome patients with 1613 literature MEN1 patients with or without pancreatic endocrine tumors

Multiple endocrine neoplasia type 1 (MEN1) is classically characterized by the development of functional or nonfunctional hyperplasia or tumors in endocrine tissues (parathyroid, pancreas, pituitary, adrenal). Because effective treatments have been developed for the hormone excess state, which was a major cause of death in these patients in the past, coupled with the recognition that nonendocrine tumors increasingly develop late in the disease course, the natural history of the disease has changed. An understanding of the current causes of death is important to tailor treatment for these patients and to help identify prognostic factors; however, it is generally lacking.To add to our understanding, we conducted a detailed analysis of the causes of death and prognostic factors from a prospective long-term National Institutes of Health (NIH) study of 106 MEN1 patients with pancreatic endocrine tumors with Zollinger-Ellison syndrome (MEN1/ZES patients) and compared our results to those from the pooled literature data of 227 patients with MEN1 with pancreatic endocrine tumors (MEN1/PET patients) reported in case reports or small series, and to 1386 patients reported in large MEN1 literature series. In the NIH series over a mean follow-up of 24.5 years, 24 (23%) patients died (14 MEN1-related and 10 non-MEN1-related deaths). Comparing the causes of death with the results from the 227 patients in the pooled literature series, we found that no patients died of acute complications due to acid hypersecretion, and 8%-14% died of other hormone excess causes, which is similar to the results in 10 large MEN1 literature series published since 1995. In the 2 series (the NIH and pooled literature series), two-thirds of patients died from an MEN1-related cause and one-third from a non-MEN1-related cause, which agrees with the mean values reported in 10 large MEN1 series in the literature, although in the literature the causes of death varied widely. In the NIH and pooled literature series, the main causes of MEN1-related deaths were due to the malignant nature of the PETs, followed by the malignant nature of thymic carcinoid tumors. These results differ from the results of a number of the literature series, especially those reported before the 1990s. The causes of non-MEN1-related death for the 2 series, in decreasing frequency, were cardiovascular disease, other nonendocrine tumors > lung diseases, cerebrovascular diseases. The most frequent non-MEN1-related tumor deaths were colorectal, renal > lung > breast, oropharyngeal. Although both overall and disease-related survival are better than in the past (30-yr survival of NIH series: 82% overall, 88% disease-related), the mean age at death was 55 years, which is younger than expected for the general population.Detailed analysis of causes of death correlated with clinical, laboratory, and tumor characteristics of patients in the 2 series allowed identification of a number of prognostic factors. Poor prognostic factors included higher fasting gastrin levels, presence of other functional hormonal syndromes, need for >3 parathyroidectomies, presence of liver metastases or distant metastases, aggressive PET growth, large PETs, or the development of new lesions.The results of this study have helped define the causes of death of MEN1 patients at present, and have enabled us to identify a number of prognostic factors that should be helpful in tailoring treatment for these patients for both short- and long-term management, as well as in directing research efforts to better define the natural history of the disease and the most important factors determining long-term survival at present.

Multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN1) is characterized by the occurrence of parathyroid, pancreatic islet and anterior pituitary tumors. Some patients may also develop carcinoid tumors, adrenocortical tumors, facial angiofibromas, collagenomas, and lipomas. MEN1 is an autosomal-dominant disorder, due to mutations in the tumor suppressor gene MEN1, which encodes a 610 amino acid protein, menin. Thus, the finding of MEN1 in a patient has important implications for family members because first-degree relatives have a 50% risk of developing the disease and can often be identified by MEN1 mutational analysis. Patients with MEN1 have a decreased life-expectancy and the outcomes of current treatments, which are generally similar to that for the respective tumors occurring in non-MEN1 patients, are not as successful because of multiple tumors, which may be larger, more aggressive, and resistant to treatment, and the concurrence of metastases. The prognosis for MEN1 patients might be improved by pre-symptomatic tumor detection and undertaking treatment specific for MEN1-tumors. Thus, it is recommended that MEN1 patients and their families should be cared for by multi-disciplinary teams comprising relevant specialists with experience in the diagnosis and treatment of patients with endocrine tumors.

Proliferation rates of multiple endocrine neoplasia type 1 (MEN1)-associated tumors

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by the combined occurrence of parathyroid and adrenocortical tumors, and neuroendocrine tumors (NETs) of the pancreas and pituitary. The pancreatic NETs are predominantly gastrinomas and insulinomas, and the pituitary NETs are mostly prolactinomas and somatotrophinomas. We postulated that the different types of pancreatic and pituitary NETs may be partly due to differences in their proliferation rates, and we therefore assessed these in MEN1-associated tumors and gonadal tumors that developed in mice deleted for an Men1 allele (Men1(+/-)). To label proliferating cells in vivo, Men1(+/-) and wild-type (Men1(+/+)) mice were given 5-bromo-2-deoxyuridine (BrdU) in drinking water from 1-12 wk, and tissue sections were immunostained using anti-BrdU and hormone-specific antibodies. Proliferation in the tumors of Men1(+/-) mice was significantly (P < 0.001) increased when compared with the corresponding normal Men1(+/+) tissues. Pancreatic, pituitary and adrenocortical proliferation fitted first- and second-order regression lines in Men1(+/+) tissues and Men1(+/-) tumors, respectively, R(2) = 0.999. Apoptosis was similar in Men1(+/-) pancreatic, pituitary, and parathyroid tumors when compared with corresponding normal tissues, decreased in Men1(+/-) adrenocortical tumors, but increased in Men1(+/-) gonadal tumors. Mathematical modeling of NET growth rates (proliferation minus apoptosis rates) predicted that in Men1(+/-) mice, only pancreatic β-cells, pituitary lactotrophs and somatotrophs could develop into tumors within a murine lifespan. Thus, our studies demonstrate that Men1(+/-) tumors have low proliferation rates (<2%), second-order kinetics, and the higher occurrence of insulinomas, prolactinomas, and somatotrophinomas in MEN1 is consistent with a mathematical model for NET proliferation.

Clinical practice guidelines for multiple endocrine neoplasia type 1 (MEN1)

OBJECTIVE

The aim was to provide guidelines for evaluation, treatment, and genetic testing for multiple endocrine neoplasia type 1 (MEN1).

PARTICIPANTS

The group, which comprised 10 experts, including physicians, surgeons, and geneticists from international centers, received no corporate funding or remuneration.

PROCESS

Guidelines were developed by reviews of peer-reviewed publications; a draft was prepared, reviewed, and rigorously revised at several stages; and agreed-upon revisions were incorporated.

CONCLUSIONS

MEN1 is an autosomal dominant disorder that is due to mutations in the tumor suppressor gene MEN1, which encodes a 610-amino acid protein, menin. Thus, the finding of MEN1 in a patient has important implications for family members because first-degree relatives have a 50% risk of developing the disease and can often be identified by MEN1 mutational analysis. MEN1 is characterized by the occurrence of parathyroid, pancreatic islet, and anterior pituitary tumors. Some patients may also develop carcinoid tumors, adrenocortical tumors, meningiomas, facial angiofibromas, collagenomas, and lipomas. Patients with MEN1 have a decreased life expectancy, and the outcomes of current treatments, which are generally similar to those for the respective tumors occurring in non-MEN1 patients, are not as successful because of multiple tumors, which may be larger, more aggressive, and resistant to treatment, and the concurrence of metastases. The prognosis for MEN1 patients might be improved by presymptomatic tumor detection and undertaking treatment specific for MEN1 tumors. Thus, it is recommended that MEN1 patients and their families should be cared for by multidisciplinary teams comprising relevant specialists with experience in the diagnosis and treatment of patients with endocrine tumors.

Malignant pancreatic tumors in children: a single-institution series

BACKGROUND

Pancreatic tumors in children represent a very rare entity. We reviewed the clinical and pathologic features of pediatric patients with pancreatic tumors at a single institution.

METHODS

We conducted a retrospective review of cases diagnosed at the Hospital for Sick Children between 1986 and 2010.

RESULTS

Twenty-seven patients were diagnosed during the study period: 18 with solid pseudopapillary neoplasm (SPN), 6 with pancreatic endocrine neoplasia, and 3 with other tumors. Of the 27 children, 3 had associated syndromes, in specific tuberous sclerosis, von Hippel-Lindau, and polycystic ovarian syndrome. The most common symptoms were pain and vomiting in SPN and hypoglycemia and seizures in insulinomas. Magnetic resonance imaging and computed tomographic scan were equally accurate in determining size and site of origin of the tumor, and both were better than ultrasound. All patients underwent surgery (distal pancreatectomy in 14 cases, Whipple procedure in 8, other procedures in 5), which represented the only treatment for all but 3 cases. Seventeen patients (94%) with SPN are alive (median follow-up, 32 months), 3 of whom had positive margins. Two patients died: 1 male with SPN with malignant transformation and 1 with fibrosarcoma.

CONCLUSIONS

We describe the largest single-institution study of pediatric pancreatic tumors. Females with SPN have an excellent outcome, even in presence of positive margins, suggesting that limited surgical resection may be appropriate for these patients.

Role of multiple endocrine neoplasia type 1 mutational analysis in clinical practice

OBJECTIVE

To review and assess the role of MEN1 mutational analysis in clinical practice.

METHODS

Articles relevant to MEN1 mutation testing and screening were reviewed.

RESULTS

Multiple endocrine neoplasia type 1 (MEN 1) is an autosomal dominant disorder characterized by the combined occurrence of tumors of the parathyroid glands, pancreatic islet cells, and anterior pituitary gland. MEN 1 is associated with premature mortality attributable primarily to malignant pancreatic neuroendocrine tumors and foregut carcinoids. The MEN1 gene is located on chromosome 11q13, and germline MEN1 mutations are highly penetrant and lead to tumor development in >99% of patients by the age of 45 years. Current consensus guidelines recommend an integrated program of mutational analysis of the MEN1 gene and a combination of biochemical and radiologic screening to detect the early development of tumors and thereby reduce the morbidity and mortality associated with MEN 1. Our results reveal that MEN1 mutational analysis helps to confirm the clinical diagnosis, identify asymptomatic family members who have a MEN1 mutation and require screening from an early age, and identify the 50% of family members who do not have the MEN1 mutation and can therefore have the burden of screening and anxiety regarding potential disease removed. Moreover, MEN1 mutational analysis helps to resolve diagnostic challenges due to phenocopies, which occur in 5% to 10% of families with MEN 1.

CONCLUSION

MEN1 mutational analysis facilitates clinical management and provides benefits to patients and families with MEN 1.

Genetic susceptibility in pituitary adenomas: from pathogenesis to clinical implications

Pituitary adenomas usually present sporadically, with a multifactorial pathogenesis including somatic mutational events in cancer-related genes. Genetic predisposition implies the presence of germline DNA alterations with a range of impacts on pituitary cell biology, translating into a variable penetrance of the disease. Genetic causes must be considered in the presence of specific clinical settings, such as familial occurrence of pituitary adenoma, with or without extrapituitary diseases, and may also be suspected in young patients (<30 years of age) with macroadenomas. We review the clinical implications of genetic predisposition, with special attention on multiple endocrine neoplasia type 1, Carney complex and familial isolated pituitary adenoma. Genetic screening in selected patients with an apparently sporadic disease is also discussed.

Multiple endocrine neoplasia type 1 (MEN1)

Multiple Endocrine Neoplasia type 1 (MEN1) is an autosomal-dominant disorder characterised by the occurrence of tumours of the parathyroids, pancreas and anterior pituitary. The MEN1 gene, consists of 10 exons that encode a 610-amino acid protein referred to as Menin. Menin is predominantly a nuclear protein that has roles in transcriptional regulation, genome stability, cell division and proliferation. Germ-line mutations usually result in MEN1 or occasionally in an allelic variant referred to as Familial Isolated Hyperparathyroidism (FIHP). MEN1 tumours frequently have loss of heterozygosity (LOH) of the MEN1 locus, which is consistent with a tumour suppressor role of MEN1. Furthermore, somatic abnormalities of MEN1 have been reported in MEN1 and non-MEN1 endocrine tumours. To date, over 1300 mutations have been reported, and the majority (>70%) of these are predicted to lead to truncated forms of Menin. The mutations are scattered throughout the >9 kb genomic sequence of the MEN1 gene. Four, which consist of c.249_252delGTCT (deletion at codons 83-84), c.1546_1547insC (insertion at codon 516), c.1378C>T (Arg460Ter) and c.628_631delACAG (deletion at codons 210-211) have been reported to occur frequently in 4.5%, 2.7%, 2.6% and 2.5% of families, respectively. However, a comparison of the clinical features in patients and their families with the same mutations reveals an absence of phenotype-genotype correlations. The majority of MEN1 mutations are likely to disrupt the interactions of Menin with other proteins and thereby alter critical events in cell cycle regulation and proliferation.

Genetic screening for multiple endocrine neoplasia syndrome type 1 (MEN-1): when and how

Multiple endocrine neoplasia syndrome type 1 (MEN1) syndrome has benefited from the identification of the gene whose mutations account for the genetic susceptibility to develop endocrine tumors. Asymptomatic MEN1 mutant carriers need to be clearly recognized because the gene-related mutations confer a high risk of multiple primary cancers, occur at younger ages, and affect multiple family members who inherit the cancer-predisposing genetic mutation.