Prospective study of surgery for primary hyperparathyroidism (HPT) in multiple endocrine neoplasia-type 1 and Zollinger-Ellison syndrome: Long-term outcome of a more virulent form of HPT. Ann Surg. 2008;247:501-510. [PMID: 18376196 DOI: 10.1097/sla.0b013e31815efda5]

Progress report on multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN1) syndrome is an autosomal dominant disorder caused by a germline pathogenic variant in the MEN1 tumor suppressor gene. Patients with MEN1 have a high risk for primary hyperparathyroidism (PHPT) with a penetrance of nearly 100%, pituitary adenomas (PitAd) in 40% of patients, and neuroendocrine neoplasms (NEN) of the pancreas (40% of patients), duodenum, lung, and thymus. Increased MEN1-related mortality is mainly related to duodenal-pancreatic and thymic NEN. Management of PHPT differs from that of patients with sporadic disease, as the surgical approach in MEN1-related PHPT includes near-total or total parathyroidectomy because of multigland hyperplasia in most patients and the consequent high risk of recurrence. NEN management also differs from patients with sporadic disease due to multiple synchronous and metasynchronous neoplasms. In addition, the lifelong risk of developing NEN requires special considerations to avoid excessive surgeries and to minimize damage to the patient's function and well-being. This progress report will outline current insights into surveillance and management of the major clinical manifestation of MEN1 syndrome in children and adults with MEN1 diagnosis. In addition, we will discuss MEN1-like clinical presentation with negative MEN1-genetic workup and future clinical and research directions.

Chapter 6: Syndromic primary hyperparathyroidism

Syndromic primary hyperparathyroidism has several features in common: younger age at diagnosis when compared with sporadic primary hyperparathyroidism, often synchronous or metachronous multi-glandular involvement, higher possibility of recurrence, association with other endocrine or extra-endocrine disorders, and suggestive family background with autosomal dominant inheritance. Hyperparathyroidism in multiple endocrine neoplasia type 1 is the most common syndromic hyperparathyroidism. It is often asymptomatic in adolescents and young adults, but may be responsible for recurrent lithiasis and/or bone loss. Hyperparathyroidism-jaw tumor syndrome is less frequent, but often immediately symptomatic, with higher blood calcium levels, and is sometimes associated with an atypic parathyroid tumor or parathyroid carcinoma. Hyperparathyroidism in multiple endocrine neoplasia type 2A is not at the forefront of the clinical picture, rarely revealing the disease, and often manifests with few symptoms. Multiple endocrine neoplasia type 4 is a more recently described entity, in which hyperparathyroidism seems to occur later and be less severe than in previous syndromes. In all cases, the indications and modalities of surgical treatment should be discussed in an expert center. The risk of recurrence after surgery, particularly high in multiple endocrine neoplasia type 1, requires long-term monitoring.

Impact of fresh grape juice on the pharmacokinetics of omeprazole: results of a food-drug interaction study

Grapes have been widely used for dietary ailments due to their attributed pharmacological activities. Resveratrol, the chief constituent of grapes, is responsible for their pharmacological benefits. However, apart from their beneficial effects, grapes have also recently been considered in drug interaction studies. This study investigated the pharmacokinetic profile of omeprazole administered alone compared to omeprazole administered with grape juice, with a prior intake of grape juice, for 1 continuous week. The study was conducted on two groups of healthy male volunteers [n = 12]. One group was orally administered 40 mg of omeprazole alone, while the other group was administered omeprazole with grape juice. Blood samples were analyzed for omeprazole concentration by a reverse-phase HPLC method. Co-administration of 40 mg omeprazole with grape juice significantly decreased the AUC0-t and Cmax by 32% and 34%, respectively, suggesting a role being played by grapes in the activation of P-glycoprotein and omeprazole metabolizing enzymes, including CYP3A4 and CYP2C19. In conclusion, the addition of grapes as a dietary supplement in patients taking omeprazole for the management of peptic ulcer symptoms may lead to a higher required dose of omeprazole.

Evaluation and Surgical Management of Multiple Endocrine Neoplasias

Multiple endocrine neoplasia (MEN) syndromes are rare autosomal dominant diseases that are associated with a mixture of both endocrine and non-endocrine tumors. Traditionally, there are 2 types of MEN that have unique clinical associations: MEN 1 (parathyroid hyperplasia, pancreatic neuroendocrine tumors, and pituitary tumors) and MEN 2 (medullary thyroid carcinoma and pheochromocytoma), which is further classified into MEN 2A (adds parathyroid adenomas) and 2B (adds ganglioneuromas and marfanoid habitus). Many of the endocrine tumors are resected surgically, and the pre, intra, and postoperative management strategies used must take into account the high recurrence rates asscioated with MEN tumors.

Recurrence After Surgery for Primary Hyperparathyroidism in 517 Patients With Multiple Endocrine Neoplasia Type 1: An Association Francophone de Chirurgie Endocrinienne and Groupe d'étude des Tumeurs Endocrines study

OBJECTIVE

To assess recurrence according to the type of surgery for primary hyperparathyroidism (pHPT) in multiple endocrine neoplasia type 1 ( MEN1 ) patients and to identify the risk factors for recurrence after the initial surgery.

BACKGROUND

In MEN1 patients, pHPT is multiglandular, and the optimal extent of initial parathyroid resection influences the risk of recurrence.

METHODS

MEN1 patients who underwent initial surgery for pHPT between 1990 and 2019 were included. Persistence and recurrence rates after less than subtotal parathyroidectomy (LTSP) and subtotal parathyroidectomy (STP) were analyzed. Patients with total parathyroidectomy with reimplantation were excluded.

RESULTS

Five hundred seventeen patients underwent their first surgery for pHPT: 178 had LTSP (34.4%) and 339 STP (65.6%). The recurrence rate was significantly higher after LTSP (68.5%) than STP (45%) ( P < 0.001). The median time to recurrence after pHPT surgery was significantly shorter after LTSP than after STP: 4.25 (1.2-7.1) versus 7.2 (3.9-10.1) years ( P < 0.001). A mutation in exon 10 was an independent risk factor of recurrence after STP (odds ratio = 2.19; 95% CI: 1.31; 3.69; P = 0.003). The 5 and 10-year recurrent pHPT probabilities were significantly higher in patients after LTSP with a mutation in exon 10 (37% and 79% vs 30% and 61%; P = 0.016).

CONCLUSIONS

Persistence, recurrence of pHPT, and reoperation rate are significantly lower after STP than LTSP in MEN1 patients. Genotype seems to be associated with the recurrence of pHPT. A mutation in exon 10 is an independent risk factor for recurrence after STP, and LTSP may not be recommended when exon 10 is mutated.

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 Type 1 Syndrome Pancreatic Neuroendocrine Tumor Genotype/Phenotype: Is There Any Advance on Predicting or Preventing?

Multiple endocrine neoplasia type 1 syndrome (MEN1) is a disease caused by mutations in the MEN1 tumor suppressor gene leading to hyperparathyroidism, pituitary adenomas, and entero-pancreatic neuroendocrine tumors. Pancreatic neuroendocrine tumors (PNETs) are a major cause of mortality in patients with MEN1. Identification of consistent genotype-phenotype correlations has remained elusive, but MEN1 mutations in exons 2, 9, and 10 may be associated with metastatic PNETs; patients with these mutations may benefit from more intensive surveillance and aggressive treatment. In addition, epigenetic differences between MEN1-associated PNETs and sporadic PNETs are beginning to emerge, but further investigation is required to establish clear phenotypic associations.

Successful Lifetime/Long-Term Medical Treatment of Acid Hypersecretion in Zollinger-Ellison Syndrome (ZES): Myth or Fact? Insights from an Analysis of Results of NIH Long-Term Prospective Studies of ZES

Analysis of the efficacy/pharmacology of long-term/lifetime medical treatment of acid hypersecretion in a large cohort of ZES patients in a prospective study. This study includes the results from all 303 patients with established ZES who were prospectively followed and received acid antisecretory treatment with either H2Rs or PPIs, with antisecretory doses individually titrated by the results of regular gastric acid testing. The study includes patients treated for short-term periods (<5 yrs), patients treated long-term (>5 yrs), and patients with lifetime treatment (30%) followed for up to 48 years (mean 14 yrs). Long-term/lifelong acid antisecretory treatment with H2Rs/PPIs can be successfully carried out in all patients with both uncomplicated and complicated ZES (i.e., with MEN1/ZES, previous Billroth 2, severe GERD). This is only possible if drug doses are individually set by assessing acid secretory control to establish proven criteria, with regular reassessments and readjustments. Frequent dose changes both upward and downward are needed, as well as regulation of the dosing frequency, and there is a primary reliance on the use of PPIs. Prognostic factors predicting patients with PPI dose changes are identified, which need to be studied prospectively to develop a useful predictive algorithm that could be clinically useful for tailored long-term/lifetime therapy in these patients.

Classical and Nonclassical Manifestations of Primary Hyperparathyroidism

This narrative review summarizes data on classical and nonclassical manifestations of primary hyperparathyroidism (PHPT). It is based on a rigorous literature search, inclusive of a Medline search for systematic reviews from 1940 to December 2020, coupled with a targeted search for original publications, covering four databases, from January 2013-December 2020, and relevant articles from authors' libraries. We present the most recent information, identify knowledge gaps, and suggest a research agenda. The shift in the presentation of PHPT from a predominantly symptomatic to an asymptomatic disease, with its varied manifestations, has presented several challenges. Subclinical nephrolithiasis and vertebral fractures are common in patients with asymptomatic disease. The natural history of asymptomatic PHPT with no end organ damage at diagnosis is unclear. Some observational and cross-sectional studies continue to show associations between PHPT and cardiovascular and neuropsychological abnormalities, among the different disease phenotypes. Their causal relationship is uncertain. Limited new data are available on the natural history of skeletal, renal, cardiovascular, neuropsychological, and neuromuscular manifestations and quality of life. Normocalcemic PHPT (NPHPT) is often diagnosed without the fulfillment of rigorous criteria. Randomized clinical trials have not demonstrated a consistent long-term benefit of parathyroidectomy (PTX) versus observation on nonclassical manifestations. We propose further refining the definition of asymptomatic disease, into two phenotypes: one without and one with evidence of target organ involvement, upon the standard evaluation detailed in our recommendations. Each of these phenotypes can present with or without non-classical manifestations. We propose multiple albumin-adjusted serum calcium determinations (albumin-adjusted and ionized) and exclusion of all secondary causes of high parathyroid hormone (PTH) when establishing the diagnosis of NPHPT. Refining the definition of asymptomatic disease into the phenotypes proposed will afford insights into their natural history and response to interventions. This would also pave the way for the development of evidence-based guidance and recommendations. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Surgical Aspects of Primary Hyperparathyroidism

Parathyroidectomy (PTX) is the treatment of choice for symptomatic primary hyperparathyroidism (PHPT). It is also the treatment of choice in asymptomatic PHPT with evidence for target organ involvement. This review updates surgical aspects of PHPT and proposes the following definitions based on international expert consensus: selective PTX (and reasons for conversion to an extended procedure), bilateral neck exploration for non-localized or multigland disease, subtotal PTX, total PTX with immediate or delayed autotransplantation, and transcervical thymectomy and extended en bloc PTX for parathyroid carcinoma. The systematic literature reviews discussed covered (i) the use of intraoperative PTH (ioPTH) for localized single-gland disease and (ii) the management of low BMD after PTX. Updates based on prospective observational studies are presented concerning PTX for multigland disease and hereditary PHPT syndromes, histopathology, intraoperative adjuncts, localization techniques, perioperative management, "reoperative" surgery and volume/outcome data. Postoperative complications are few and uncommon (<3%) in centers performing over 40 PTXs per year. This review is the first global consensus about surgery in PHPT and reflects the current practice in leading endocrine surgery units worldwide. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Ultrasound-Guided Radiofrequency Ablation for Primary Hyperparathyroidism Induced by Multiple Endocrine Neoplasia 1—A Case Report

Multiple endocrine neoplasia type 1 (MEN1) is a syndrome characterized by the occurrence of two or more endocrine gland tumors. Here, we show a case of a 52-year-old man diagnosed with MEN1 through gastrinoma, parathyroid adenoma and gene detection. The MEN1 patient’s case was complicated with relapsed primary hyperparathyroidism (PHPT), and they received ultrasound-guided radiofrequency ablation (RFA). The patient had a remarkable recovery after RFA treatment for the relapsed PHPT. It might be an alternative treatment for MEN1 patients with poor conditions such as high surgical risk, unwillingness to choose parathyroid surgery or those unable to tolerate surgery. Individualized therapy significantly benefits the prognosis of MEN1 patients.

Less Than Subtotal Parathyroidectomy for Multiple Endocrine Neoplasia Type 1 Primary Hyperparathyroidism: A Systematic Review and Meta-Analysis

BACKGROUND

Multiple endocrine neoplasia type 1 (MEN1)-associated primary hyperparathyroidism (pHPT) is classically associated with an asymmetric and asynchronous parathyroid involvement. Subtotal parathyroidectomy (STP), which is currently the recommended surgical treatment, carries a high risk of permanent hypoparathyroidism. The results of less than subtotal parathyroidectomy (LSTP) are conflicting, and its place in this setting is still a matter of debate. The aim of this study was to identify the place of LSTP in the surgical management of patients with MEN-associated pHPT.

METHODS

A systematic literature review was conducted in accordance with PRISMA and MOOSE guidelines, for studies comparing STP and LSTP for MEN1-associated pHPT. The results of the two techniques, regarding permanent hypoparathyroidism, persistent hyperparathyroidism and recurrent hyperparathyroidism were computed using pairwise random-effect meta-analysis.

RESULTS

Twenty-five studies comparing STP and LSTP qualified for inclusion in the quantitative synthesis. In total, 947 patients with MEN1-associated pHPT were allocated to STP (n = 569) or LSTP (n = 378). LSTP reduces the risk of permanent hypoparathyroidism [odds ratio (OR) 0.29, confidence interval (CI) 95% 0.17-0.49)], but exposes to higher rates of persistent hyperparathyroidism [OR 4.60, 95% CI 2.66-7.97]. Rates of recurrent hyperparathyroidism were not significantly different between the two groups [OR 1.26, CI 95% 0.83-1.91].

CONCLUSIONS

LSTP should not be abandoned and should be considered as a suitable surgical option for selected patients with MEN1-associated pHPT. The increased risk of persistent hyperparathyroidism could improve with the emergence of more efficient preoperative localization imaging techniques and a more adequate patients selection.

Impact of parathyroidectomy on quality of life in multiple endocrine neoplasia type 1

BACKGROUND

Potential influences of parathyroidectomy (PTx) on the quality of life (QoL) in multiple endocrine neoplasia type 1-related primary hyperparathyroidism (HPT/MEN1) are unknown.

METHOD

Short Form 36 Health Survey Questionnaire was prospectively applied to 30 HPT/MEN1 patients submitted to PTx (20, subtotal; 10, total with autograft) before, 6 and 12 months after surgery. Parameters that were analyzed included QoL, age, HPT-related symptoms, general pain, comorbidities, biochemical/hormonal response, PTx type and parathyroid volume.

RESULTS

Asymptomatic patients were younger (30 vs 38 years; P = 0.04) and presented higher QoL scores than symptomatic ones: Physical Component Summary score (PCS) 92.5 vs 61.2, P = 0.0051; Mental Component Summary score (MCS) 82.0 vs 56.0, P = 0.04. In both groups, QoL remained stable 1 year after PTx, independently of the number of comorbidities. Preoperative general pain was negatively correlated with PCS (r = -0.60, P = 0.0004) and MCS (r = -0.57, P = 0.0009). Also, moderate/intense pain was progressively (6/12 months) more frequent in cases developing hypoparathyroidism. The PTx type and hypoparathyroidism did not affect the QoL at 12 months although remnant parathyroid tissue volume did have a positive correlation (P = 0.0490; r = 0.3625) to PCS 12 months after surgery. Patients with one to two comorbidities had as pre-PTx PCS (P = 0.0015) as 12 months and post-PTx PCS (P = 0.0031) and MCS (P = 0.0365) better than patients with three to four comorbidities.

CONCLUSION

A variable QoL profile was underscored in HPT/MEN1 reflecting multiple factors associated with this complex disorder as comorbidities, advanced age at PTx and presence of preoperative symptoms or of general pain perception. Our data encourage the early indication of PTx in HPT/MEN1 by providing known metabolic benefits to target organs and avoiding potential negative impact on QoL.

The role of menin in bone pathology

Multiple endocrine neoplasia type 1 (MEN1) is the most common cause of hereditary primary hyperparathyroidism (PHPT). Bone disorders are considered one of the key symptoms in PHPT present with the significant reduction in bone mineral density and low-energy fractures. Previously, these bone disorders were believed to be caused solely by the increase in the level of parathyroid hormone and its subsequent effect on bone resorption. The current paradigm, however, states that the mutations in the menin gene, which cause the development of MEN1, can also affect the metabolism of the cells of the osteoid lineage. This review analyzes both the proven and the potential intracellular mechanisms through which menin can affect bone metabolism.

[Severe bone complications of primary hyperparathyroidism in a young patient with the rare verified mutation of MEN1]

Multiple endocrine neoplasia type 1 syndrome (MEN1) is a rare inherited disorder that can include combinations of more than 20 endocrine and non-endocrine tumors. Unfortunately, none of the described MEN1 mutations has been associated with a peculiar clinical phenotype, even within members of the same family, thus a genotype-to-phenotype correlation does not exist. MEN1 syndrome is the most common cause of hereditary primary hyperparathyroidism (PHPT), the disease penetrance of which exceeds 50% by the age of 20 and reaches 95% by the age of 40. At the same time, PHPT with hyperplasia or adenomas of the parathyroid glands (PTG) is the most distinctive manifestation of the MEN1 syndrome. One of the main symptoms of PHPT, both in sporadic and hereditary forms of the disease, is bone damage. At the time of diagnosis in PHPT/MEN1, the bone mineral density is generally lower in comparison with the sporadic form of PHPT. This may be due to excessive secretion of parathyroid hormone during the period of peak bone mass, concomitant components of the syndrome, extended surgical treatment, and the direct effect of a mutation in the menin gene on bone remodeling. This clinical case describes a young patient with severe bone complications of PHPT and uncertain rare MEN1 mutation. PHPT was diagnosed five years later from the first onset of bone complications and repeated orthopedic operations. There was the «hungry bones» syndrome after successful surgery of PHPT, which was managed with vitamin D and calcium carbonate supplementation and there is a positive dynamic in increased bone mineral density in the main skeleton after 6 months.

Gastrinoma and Zollinger Ellison syndrome: A roadmap for the management between new and old therapies

Zollinger-Ellison syndrome (ZES) associated with pancreatic or duodenal gastrinoma is characterized by gastric acid hypersecretion, which typically leads to gastroesophageal reflux disease, recurrent peptic ulcers, and chronic diarrhea. As symptoms of ZES are nonspecific and overlap with other gastrointestinal disorders, the diagnosis is often delayed with an average time between the onset of symptoms and final diagnosis longer than 5 years. The critical step for the diagnosis of ZES is represented by the initial clinical suspicion. Hypergastrinemia is the hallmark of ZES; however, hypergastrinemia might recognize several causes, which should be ruled out in order to make a final diagnosis. Gastrin levels > 1000 pg/mL and a gastric pH below 2 are considered to be diagnostic for gastrinoma; some specific tests, including esophageal pH-recording and secretin test, might be useful in selected cases, although they are not widely available. Endoscopic ultrasound is very useful for the diagnosis and the local staging of the primary tumor in patients with ZES, particularly in the setting of multiple endocrine neoplasia type 1. Some controversies about the management of these tumors also exist. For the localized stage, the combination of proton pump inhibitory therapy, which usually resolves symptoms, and surgery, whenever feasible, with curative intent represents the hallmark of gastrinoma treatment. The high expression of somatostatin receptors in gastrinomas makes them highly responsive to somatostatin analogs, supporting their use as anti-proliferative agents in patients not amenable to surgical cure. Other medical options for advanced disease are super-imposable to other neuroendocrine neoplasms, and studies specifically focused on gastrinomas only are scant and often limited to case reports or small retrospective series. The multidisciplinary approach remains the cornerstone for the proper management of this composite disease. Herein, we reviewed available literature about gastrinoma-associated ZES with a specific focus on differential diagnosis, providing potential diagnostic and therapeutic algorithms.

[The clinical practice guidelines for primary hyperparathyroidism, short version]

Primary hyperparathyroidism (PHPT) is an endocrine disorder of parathyroid glands characterized by excessive secretion of parathyroid hormone (PTH) with an upper normal or elevated blood calcium level. Classical PHPT refers to a symptomatic, multi-system disorder, wich can lead to a significant decrease in the quality of life, disability of patients, and even an increased risk of premature death. Hypercalcemia and the catabolic effect of PTH on various cells are considered as the main pathogenetic mechanisms of the PHPT associated complications. In the last two decades, there has been an increase in the incidence of PHPT, mainly due to the mild forms of the disease, primarily due to the routine calcium screening in North America, Western Europe and, Asia. High prevalence of the disease, as well as the variety of clinical manifestations, cause the attention of different specialists - physicians, rheumatologists, urologists, nephrologists, cardiologists and other doctors. This review cover the main issues of Russian guidelines for the management of PHPT, approved in 2020, including laboratory and instrumental methods, differential diagnosis, surgical and conservative approach, short-term and long-term follow-up. This guidelines also include the recommendations for special groups of patients with hereditary forms of PHPT, parathyroid carcinoma, PHPT during pregnancy.

Multimodality Imaging Review of Multiple Endocrine Neoplasia

OBJECTIVE. The purpose of this article is to review the clinical manifestations, endocrine tumors types, and multimodality diagnostic tools available to physicians involved in the management of patients with multiple endocrine neoplasia (MEN) syndrome, in addition to discussing relevant imaging findings and appropriate imaging follow-up. CONCLUSION. Thorough knowledge of the spectrum of tumors associated with MEN gene mutations aids in the screening, diagnostic workup, and posttreatment monitoring of patients with MEN-related gene mutations.

Multiple endocrine neoplasia type 1 (MEN-1) and neuroendocrine neoplasms (NENs)

Neuroendocrine neoplasms (NENs) are relatively rare neoplasms with 6.4-times increasing age-adjusted annual incidence during the last four decades. NENs arise from neuroendocrine cells, which release hormones in response to neuronal stimuli and they are distributed into organs and tissues. The presentation and biological behaviour of the NENs are highly heterogeneous, depending on the organ. The increased incidence is mainly due to increased awareness and improved detection methods both in the majority of sporadic NENs (non-inherited), but also the inherited groups of neoplasms appearing in at least ten genetic syndromes. The most important one is multiple endocrine neoplasia type 1 (MEN-1), caused by mutations in the tumour suppressor gene MEN1. MEN-1 has been associated with different tumour manifestations of NENs e.g. pancreas, gastrointestinal tract, lungs, thymus and pituitary. Pancreatic NENs tend to be less aggressive when arising in the setting of MEN-1 compared to sporadic pancreatic NENs. There have been very important improvements over the past years in both genotyping, genetic counselling and family screening, introduction and validation of various relevant biomarkers, as well as newer imaging modalities. Alongside this development, both medical, surgical and radionuclide treatments have also advanced and improved morbidity, quality of life and mortality in many of these patients. Despite this progress, there is still space for improving insight into the genetic and epigenetic factors in relation to the biological mechanisms determining NENs as part of MEN-1. This review gives a comprehensive update of current evidence for co-occurrence, diagnosis and treatment of MEN-1 and neuroendocrine neoplasms and highlight the important progress now finding its way to international guidelines in order to improve the global management of these patients.

Primary Hyperparathyroidism: A Narrative Review of Diagnosis and Medical Management

Primary hyperparathyroidism (PHPT) is the most common cause of hypercalcemia in the outpatient setting. Symptomatic presentation includes non-specific signs and symptoms of hypercalcemia, skeletal fragility, nephrolithiasis and nephrocalcinosis. The majority of individuals present at an asymptomatic stage following routine biochemical screening, without any signs or symptoms of calcium or parathyroid hormone (PTH) excess or target organ damage. Indications for surgery have recently been revised as published in recent guidelines and consensus statements. Parathyroidectomy is advised in patients younger than 50 years old and in the presence of either significant hypercalcemia, impaired renal function, renal stones or osteoporosis. Surgery is always appropriate in suitable surgical candidates, however, medical management may be considered in those with mild asymptomatic disease, contraindications to surgery or failed previous surgical intervention. We summarized the optimal medical interventions available in the care of PHPT patients not undergoing parathyroidectomy. Calcium and vitamin D intake should be optimized. Antiresorptive therapy may be used for skeletal protection in patients with an increased fracture risk. Cinacalcet, a calcimimetic agent, has been shown to effectively lower serum calcium and PTH levels. The effect of medical treatment on the reduction in fracture risk is unknown and should be the focus of future research.

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.

A Parathyroid-Gut Axis: Hypercalcemia and the Pathogenesis of Gastrinoma in Multiple Endocrine Neoplasia 1

Patients with multiple endocrine neoplasia 1 (MEN1) syndrome have a germline mutation in the MEN1 gene. Loss of the wild-type allele can initiate endocrine tumorigenesis. Microscopic and macroscopic pituitary, parathyroid, and pancreatic tumors (referred to as the 3 P's) show loss of the wild-type MEN1 allele up to 100%. In contrast, the duodenal gastrinoma pathogenesis in MEN1 syndrome follows a hyperplasia-to-neoplasia sequence. Gastrinomas have loss of heterozygosity of the MEN1 locus in <50%, and invariably coincide with linear, diffuse, or micronodular gastrin-cell hyperplasia. The factor initiating the gastrin-cell hyperplasia-to-neoplasia sequence is unknown. In this perspective, we argue that hypercalcemia may promote the gastrin-cell hyperplasia-to-neoplasia sequence through the calcium sensing receptor. Hypercalcemia is present in almost all patients with MEN1 syndrome due to parathyroid adenomas. We propose a parathyroid-gut axis, which could well explain why patients with MEN1 syndrome are regularly cured of duodenal gastrinoma after parathyroid surgery, and might cause MEN1 syndrome phenocopies in MEN1-mutation negative individuals with parathyroid adenomas. This perspective on the pathogenesis of the gastrin-cell hyperplasia and neoplasia sequence sheds new light on tumorigenic mechanisms in neuroendocrine tumors and might open up novel areas of gastrinoma research. It may also shift focus in the treatment of MEN1 syndrome-related gastrinoma to biochemical prevention.

Perspectives on the current pharmacotherapeutic strategies for management of functional neuroendocrine tumor syndromes

Introduction: In the past, controlling the hormone-excess-state was the main determinant of survival in Functional-Neuroendocrine-Neoplasm-syndromes (F-NENs). This was difficult because the pharmacological-armamentarium available was limited. Recently, new therapeutic strategies have increased but it also generated controversies/uncertainties.Areas covered: The authors briefly review: established/proposed F-NENs; the rationale for treatments; the recommended initial-pharmacotherapeutic-approach to controlling F-NENs hormone-excess-state; the secondary-approaches if the initial approach fails or resistance develops; and the approach to deal with the malignant nature of the NEN. Also discussed are controversies/uncertainties related to new treatments.Expert opinion: Unfortunately, except for patients with insulinomas (>90-95%), gastrinomas (<20-40%), a minority with the other F-panNENs and 0-<1% with Carcinoid-syndrome is curative-surgery possible. Except for insulinomas, gastrinomas, and ACTHomas, long-acting somatostatin-analogs are the initial-pharmacological-treatments for hormone-excess-state. For insulinomas prior to surgery/malignancy, diazoxide is the initial drug-treatment; for gastrinomas, oral PPIs; and for ACTHomas, steroidogenesis inhibitors. There are now several secondary pharmacotherapeutic treatments. Surgery and liver-directed therapies also have a role in selected patients. Particularly promising is the recent results with PRRT for the hormone-excess-state, independent of its anti-growth effect. The sequence to use various agents and the approach to syndrome diagnosis while taking various agents remains unclear/controversial in many cases.

Optimal extent of initial parathyroid resection in patients with multiple endocrine neoplasia syndrome type 1: A meta-analysis

BACKGROUND

Hyperparathyroidism is an almost universal feature of multiple endocrine neoplasia type 1 syndrome. We present a systematic review and meta-analysis of the postoperative outcomes of patients undergoing initial operative treatment of primary hyperparathyroidism complicating multiple endocrine neoplasia 1.

METHODS

A comprehensive literature search was performed with a priori defined exclusion criteria for studies comparing total parathyroidectomy, subtotal parathyroidectomy, and less than subtotal parathyroidectomy.

RESULTS

Twenty-one studies incorporating 1,131 patients (272 undergoing total parathyroidectomy, 510 subtotal parathyroidectomy, and 349 less than subtotal parathyroidectomy) were identified. Pooled results revealed increased risk for long-term hypoparathyroidism in total parathyroidectomy patients (relative risk 1.61; 95% confidence interval, 1.12-2.31; P = .009) versus those undergoing subtotal parathyroidectomy. In the less than subtotal parathyroidectomy or subtotal parathyroidectomy comparison group, a greater risk for recurrence of hyperparathyroidism (relative risk 1.37; 95% confidence interval, 1.05-1.79; P = .02), persistence of hyperparathyroidism (relative risk 2.26; 95% confidence interval, 1.49-3.41; P = .0001), and reoperation for hyperparathyroidism (relative risk 2.48; 95% confidence interval, 1.65-3.73; P < .0001) was noted for less than subtotal parathyroidectomy patients, albeit with lesser risk for long-term for hypoparathyroidism (relative risk 0.47; 95% confidence interval, 0.29-0.75; P = .002).

CONCLUSION

Subtotal parathyroidectomy compares favorably to total parathyroidectomy, exhibiting similar recurrence and persistence rates with a decreased propensity for long-term postoperative hypoparathyroidism. The benefit of the decreased risk of hypoparathyroidism in less than subtotal parathyroidectomy is negated by the increase in the risk for recurrence, persistence, and reoperation. Future studies evaluating the performance of less than subtotal parathyroidectomy in specific multiple endocrine neoplasia 1 phenotypes should be pursued in an effort to delineate a patient-tailored, operative approach that optimizes long-term outcomes.

Multiple endocrine neoplasia type 1 revealed by a hip pathologic fracture

Multiple endocrine neoplasia type 1 is a rare autosomal inherited syndrome that affects a variety of endocrine tissues such as the parathyroid, endocrine pancreas, and anterior pituitary. Osseous complications are often misdiagnosed. We presented a case of a 46-year-old woman with pathological fractures of the lower limb. She had a history of type 1 diabetes and galactorrhea. Laboratory examinations showed hypercalcemia and an increased level of parathyroid hormone related to hyperparathyroidism. Serum chromogranin A level was increased at 9369 ng/mL (N < 102). A somatostatin receptor scintigraphy (octreoscan) revealed pathological uptake in the gastric wall, later cave adenopathy, and liver. The diagnosis of multiple endocrine neoplasia type 1 was made based on radiological and histological findings. The patient underwent a subtotal parathyroidectomy associated with somatostatin analog treatment leading to significant improvement. A literature review was conducted by searching PubMed using these following terms: multiple endocrine neoplasia type 1, hyperparathyroidism, fracture, menin, osteoporosis. We emphasized bone involvement related to multiple endocrine neoplasia type 1 syndrome. This diagnosis should be considered when pathological fractures occur in young patients with a history of endocrine disorder. We highlighted the importance of imaging features in making the diagnosis of multiple endocrine neoplasia type 1. Early management of this disease is necessary. Treatment including parathyroidectomy and somatostatin analogs leads to bone preservation and functional improvement.

Bone Metabolism and Vitamin D Implication in Gastroenteropancreatic Neuroendocrine Tumors

Patients affected by gastroenteropancreatic–neuroendocrine tumors (GEP–NETs) have an increased risk of developing osteopenia and osteoporosis, as several factors impact on bone metabolism in these patients. In fact, besides the direct effect of bone metastasis, bone health can be affected by hormone hypersecretion (including serotonin, cortisol, and parathyroid hormone-related protein), specific microRNAs, nutritional status (which in turn could be affected by medical and surgical treatments), and vitamin D deficiency. In patients with multiple endocrine neoplasia type 1 (MEN1), a hereditary syndrome associated with NET occurrence, bone damage may carry other consequences. Osteoporosis may negatively impact on the quality of life of these patients and can increment the cost of medical care since these patients usually live with their disease for a long time. However, recommendations suggesting screening to assess bone health in GEP–NET patients are missing. The aim of this review is to critically analyze evidence on the mechanisms that could have a potential impact on bone health in patients affected by GEP–NET, focusing on vitamin D and its role in GEP–NET, as well as on factors associated with MEN1 that could have an impact on bone homeostasis.

Insights into Effects/Risks of Chronic Hypergastrinemia and Lifelong PPI Treatment in Man Based on Studies of Patients with Zollinger-Ellison Syndrome

The use of proton pump inhibitors (PPIs) over the last 30 years has rapidly increased both in the United States and worldwide. PPIs are not only very widely used both for approved indications (peptic ulcer disease, gastroesophageal reflux disease (GERD), Helicobacter pylori eradication regimens, stress ulcer prevention), but are also one of the most frequently off-label used drugs (25–70% of total). An increasing number of patients with moderate to advanced gastroesophageal reflux disease are remaining on PPI indefinitely. Whereas numerous studies show PPIs remain effective and safe, most of these studies are <5 years of duration and little data exist for >10 years of treatment. Recently, based primarily on observational/epidemiological studies, there have been an increasing number of reports raising issues about safety and side-effects with very long-term chronic treatment. Some of these safety issues are related to the possible long-term effects of chronic hypergastrinemia, which occurs in all patients taking chronic PPIs, others are related to the hypo-/achlorhydria that frequently occurs with chronic PPI treatment, and in others the mechanisms are unclear. These issues have raised considerable controversy in large part because of lack of long-term PPI treatment data (>10–20 years). Zollinger–Ellison syndrome (ZES) is caused by ectopic secretion of gastrin from a neuroendocrine tumor resulting in severe acid hypersecretion requiring life-long antisecretory treatment with PPIs, which are the drugs of choice. Because in <30% of patients with ZES, a long-term cure is not possible, these patients have life-long hypergastrinemia and require life-long treatment with PPIs. Therefore, ZES patients have been proposed as a good model of the long-term effects of hypergastrinemia in man as well as the effects/side-effects of very long-term PPI treatment. In this article, the insights from studies on ZES into these controversial issues with pertinence to chronic PPI use in non-ZES patients is reviewed, primarily concentrating on data from the prospective long-term studies of ZES patients at NIH.

MEN1-associated primary hyperparathyroidism in the Spanish Registry: clinical characterictics and surgical outcomes

Primary hyperparathyroidism is the most frequent manifestation of multiple endocrine neoplasia type 1 (MEN1) syndrome. Bone and renal complications are common. Surgery is the treatment of choice, but the best timing for surgery is controversial and predictors of persistence and recurrence are not well known. Our study describes the clinical characteristics and the surgical outcomes, after surgery and in the long term, of the patients with MEN1 and primary hyperparathyroidism included in the Spanish Registry of Multiple Endocrine Neoplasia, Pheochromocytomas and Paragangliomas (REGMEN). Eighty-nine patients (49 men and 40 women, 34.2 ± 13 years old) were included. Sixty-four out of the 89 underwent surgery: a total parathyroidectomy was done in 13 patients, a subtotal parathyroidectomy in 34 and a less than subtotal parathyroidectomy in 15. Remission rates were higher after a total or a subtotal parathyroidectomy than after a less than subtotal (3/4 and 20/22 vs 7/12, P < 0.05), without significant differences in permanent hypoparathyroidism (1/5, 9/23 and 0/11, N.S.). After a median follow-up of 111 months, 20 of the 41 operated patients with long-term follow-up had persistent or recurrent hyperparathyroidism. We did not find differences in disease-free survival rates between different techniques, patients with or without permanent hypoparathyroidism and patients with different mutated exons, but a second surgery was more frequent after a less than subtotal parathyroidectomy.

Contemporary surgical management of the Zollinger-Ellison syndrome in multiple endocrine neoplasia type 1

About 30% of patients with MEN1 develop a Zollinger-Ellison syndrome. Meanwhile it is well established that the causative gastrinomas are almost exclusively localized in the duodenum and not in the pancreas, MEN1 gastrinomas occur multicentric and are associated with hyperplastic gastrin cell lesions and tiny gastrin-producing micro tumors in contrast to sporadic duodenal gastrinomas. Regardless of the high prevalence of early lymphatic metastases, the survival is generally good with an aggressive course of disease in only about 20% of patients. Symptoms can be controlled medically. The indication, timing, type, and extent of surgery are highly controversial and are discussed in detail in this article by a thorough and critical review of literature. More radical procedures, like partial pancreaticoduodenectomy, are weighed against less aggressive local excision of gastrinomas and the pros and cons of both approaches are discussed in terms of long-term morbidity, biochemical cure, and survival.

Surgical management of Zollinger-Ellison syndrome: Classical considerations and current controversies

Zollinger-Ellison syndrome (ZES) is characterized by gastric acid hypersecretion causing severe recurrent acid-related peptic disease. Excessive secretion of gastrin can now be effectively controlled with powerful proton pump inhibitors, but surgical management to control gastrinoma itself remains controversial. Based on a thorough literature review, we design a surgical algorithm for ZES and list some significant consensus findings and recommendations: (1) For sporadic ZES, surgery should be routinely undertaken as early as possible not only for patients with a precisely localized diagnosis but also for those with negative imaging findings. The surgical approach for sporadic ZES depends on the lesion location (including the duodenum, pancreas, lymph nodes, hepatobiliary tract, stomach, and some extremely rare sites such as the ovaries, heart, omentum, and jejunum). Intraoperative liver exploration and lymphadenectomy should be routinely performed; (2) For multiple endocrine neoplasia type 1-related ZES (MEN1/ZES), surgery should not be performed routinely except for lesions > 2 cm. An attempt to perform radical resection (pancreaticoduodenectomy followed by lymphadenectomy) can be made. The ameliorating effect of parathyroid surgery should be considered, and parathyroidectomy should be performed first before any abdominal surgery for ZES; and (3) For hepatic metastatic disease, hepatic resection should be routinely performed. Currently, liver transplantation is still considered an investigational therapeutic approach for ZES. Well-designed prospective studies are desperately needed to further verify and modify the current considerations.

[Diagnostics and treatment of primary hyperparathyroidism]

Primary hyperparathyroidism is a disease that occurs more frequently than generally thought and is often overlooked. Classical symptoms are bone pain and osteoporosis, renal calculi and peptic ulcers. Many patients are asymptomatic or have unspecific complaints. It is easy to establish the biochemical diagnosis based on calcium and parathormone (PTH) levels and 24-h urine calcium excretion. The most sensitive localization procedures for parathyroid adenomas are sonography and Tc-99^m-MIBI scintigraphy. The indication for surgery is undisputed in symptomatic patients; however, there is controversy concerning patients without classical symptoms. Operative therapy is highly successful. Focused operative procedures are currently available besides the traditional 4‑gland exploration. When focused techniques are used, the operative success should be confirmed by intraoperative determination of the parathormone level.

A case of hyperinsulinemic hypoglycemia related with a calcimimetic agent

We herein report a case of a 60-year-old female receiving hemodialysis who developed severe hyperinsulinemic hypoglycemia and lost her consciousness. A calcimimetic agent had been administered for the secondary hyperparathyroidism. The calcimimetic agent, mimicking the elevation of the extracellular calcium ion concentration, activates calcium-sensing receptors (CaSR) of the parathyroid cells and inhibits the parathyroid hormone secretions. The previous study suggested that the CaSR are also expressed in both human β cells and insulinoma cells, but the reactivity to change in the extracellular calcium ion concentration is different between normal β cells and insulinoma cells. After cessation of the calcimimetic agent, hypoglycemic symptoms disappeared and endogenous insulin secretion dropped to normal levels. However, the result of a prolonged fasting test indicated that she remained hyperinsulinemic even after its cessation, suggesting that she had insulinoma which could not be detected by the imaging examinations. The previous autopsy data showed that there were many cases of the insulinoma without the symptoms of hypoglycemia. We considered the possibility that she had the insulinoma and the pancreatic tumor was too small to promote the insulin secretion and cause hypoglycemia without activation by the calcimimetic agent. We should know that the calcimimetic agent could cause hyperinsulinemic hypoglycemia with the unidentified insulinoma.

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.

Impact of "Tailored" Parathyroidectomy for Treatment of Primary Hyperparathyroidism in Patients with Multiple Endocrine Neoplasia Type 1

BACKGROUND

Whether total parathyroidectomy (TPTX) or subtotal parathyroidectomy (SPTX) should be performed for primary hyperparathyroidism (PHPT) in patients with multiple endocrine neoplasia type 1 (MEN1) is controversial. At our institution, the parathyroidectomy strategy is based on the number of enlarged intraoperative parathyroid glands. We retrospectively analyzed our parathyroidectomy procedures.

METHODS

Data of PHPT treatment in patients with MEN1 who underwent parathyroidectomy from 1982 to 2012 at our department were retrospectively collected. The data were grouped according to the surgical procedure: TPTX, SPTX, and less than SPTX (LPTX). TPTX or SPTX was selected based on the preoperative examination findings and number of enlarged intraoperative parathyroid glands. The outcomes were the disease-free survival (DFS) rate and postoperative calcium replacement rate based on Kaplan-Meier analysis for each type of surgical procedure.

RESULTS

Forty-five patients were analyzed. The overall 5- and 10-year DFS was 91.7 and 55.8%, respectively. The 5- and 10-year DFS in each subgroup was 100.0 and 85.7% in the TPTX group, 89.4 and 57.3% in the SPTX group, and 91.6 and 57.3% in the LPTX group, respectively. The postoperative calcium replacement rate at 1 and 12 months was 91.7 and 58.3% in the TPTX group, 21.1 and 7.0% in the SPTX group, and 30.0 and 0.0% in the LPTX group, respectively.

CONCLUSIONS

Although LPTX was not satisfactory as a standard procedure, both SPTX and TPTX are effective treatment methods for PHPT in patients with MEN1. The parathyroidectomy strategy should be based on intraoperative evaluation of the parathyroid glands.

Gastrinomas: Medical or Surgical Treatment

This article reviews the role of surgical and medical management in patients with Zollinger-Ellison syndrome (ZES) due to a gastrin-secreting neuroendocrine tumor (gastrinoma). It concentrates on the status at present but also briefly reviews the changes over time in treatment approaches. Generally, surgical and medical therapy are complementary today; however, in some cases, such as patients with ZES and multiple endocrine neoplasia type 1, the treatment approach remains controversial.

Differential expression of miRNA199b-5p as a novel biomarker for sporadic and hereditary parathyroid tumors

MicroRNAs (miRNAs) are dysregulated in many tumors; however, miRNA regulation in parathyroid tumors remains poorly understood. To identify differentially expressed miRNAs between sporadic and hereditary parathyroid tumors and to analyze their correlation with clinicopathological features, a microarray containing 887 miRNAs was performed; then, the differentially expressed miRNAs were validated by qRT-PCR using 25 sporadic and 12 hereditary parathyroid tumors and 24 normal parathyroid tissue samples. A receiver operating characteristic curve (ROC) analysis was applied to evaluate the utility of the miRNAs for distinguishing parathyroid tumor types. Compared to the miRNAs in the normal parathyroid tissues, 10 miRNAs were differentially expressed between the sporadic and hereditary parathyroid tumors. Seven of these miRNAs (let-7i, miR-365, miR-125a-3p, miR-125a-5p, miR-142-3p, miR-193b, and miR-199b-5p) were validated in the parathyroid tumor samples. Among these miRNAs, only miR-199b-5p was differentially expressed (P < 0.001); miR-199b-5p was significantly downregulated and negatively associated with PTH levels (γ = −0.579, P = 0.002) in the sporadic tumors but was upregulated in the hereditary tumors. This miRNA showed 67% sensitivity and 100% specificity for distinguishing sporadic and hereditary parathyroid tumors. These results reveal altered expression of a miRNA between sporadic and hereditary parathyroid tumors and the potential role of miR-199b-5p as a novel biomarker for distinguishing these two types of parathyroid tumors.

The Zollinger-Ellison syndrome: is there a role for somatostatin analogues in the treatment of the gastrinoma?

PURPOSE

Analyze the role of somatostatin analogues (SSAs) in the treatment of sporadic and MEN1-related gastrinomas, trying to define whether recent trials have changed the landscape of gastrinoma therapy.

METHODS

We evaluate the rationale of SSA use in the treatment of gastrinomas, summarize the current literature concerning the effect of SSAs on the control of Zollinger-Ellison syndrome (ZES) and gastrinomas tumor progression and discuss their role in the most recent guidelines.

RESULTS

The medical treatment of gastrinoma and related ZES is aimed at controlling acid hypersecretion and tumor progression, in inoperable patients. The use of proton pump inhibitors (PPIs) to control the syndrome is a cornerstone in the ZES therapy. SSAs are not usually indicated for antisecretory purpose, because PPIs are considered the treatment of choice, due to their long lasting high efficacy and oral availability. The antiproliferative effect of SSAs has been established by two placebo-controlled trials that have clearly demonstrated a significant increase in progression free survival in patients affected by non-functioning well-differentiated advanced neuroendocrine tumors (NETs). The recent ENETS guidelines recommend the use of SSAs in advanced well differentiated NETs as antiproliferative agents.

CONCLUSIONS

The high sstr-expression in gastrinomas make them highly responsive to SSAs and support the use of such drugs to counteract the tumour growth in patients not amenable to surgical cure. Unfortunately, limited data, mainly case reports or small series, support the use of SSAs in advanced gastrinomas, therefore, it is difficult to quantify their ability to control tumour growth and disease progression.

Intraoperative Decision-Making and Technical Aspects of Parathyroidectomy in Young Patients With MEN1 Related Hyperparathyroidism

One in 5,000 to 1 in 50,000 births have multiple endocrine neoplasia type 1 (MEN1). MEN1 is a hereditary syndrome clinically defined by the presence of two of the following endocrine tumors in the same patient: parathyroid adenomas, entero-pancreatic endocrine tumors and pituitary tumors. Most commonly, patients with MEN1 manifest primarily with signs and symptoms linked to primary hyperparathyroidism. By age 50, it is estimated that 100% of patients with MEN1 will have been diagnosed with primary hyperparathyroidism. These patients will need to undergo resection of their hyperfunctioning glands, however there is no clear consensus on which procedure to perform and when to perform it in these patients. In this original study we describe and explain the rational of our peri-operative approach and management at MD Anderson Cancer Center of MEN1 patients with hyperparathyroidism. This protocol includes preoperative evaluation, intraoperative decision-making and detailed surgical technique adopted for these patients' care. Additionally we review follow-up and disease management in instances of recurrent primary hyperparathyroidism in patients with MEN1 syndrome.

Diagnosis of Zollinger-Ellison syndrome in the era of PPIs, faulty gastrin assays, sensitive imaging and limited access to acid secretory testing

In recent years the diagnosis of Zollinger-Ellison syndrome (ZES) has become increasingly controversial with several new approaches and criteria proposed, differing from the classical biochemical criterion of inappropriate hypergastrinemia (i.e., hypergastrinemia in the presence of hyperchlorhydria) (Table 1). These changes have come about because of the difficulty and potential dangers of stopping proton pump inhibitors (PPIs) for gastric acid analysis; the recognition than many of the current assays used to assess gastrin concentrations are unreliable; the development of sensitive imaging modalities that detect neuroendocrine tumors (NETs) including an increasing number of the primary gastrinomas; the increased use of percutaneous or endoscopic ultrasound (EUS)-directed biopsies/cytology and the general lack of availability of acid secretory testing. In this article we will discuss the basis for these controversies, review the proposed changes in diagnostic approaches and make recommendations for supporting the diagnosis of ZES in the modern era.

The future: diagnostic and imaging advances in MEN1 therapeutic approaches and management strategies

Prospective randomized data are lacking, but current clinical expert guidelines recommend annual screening examinations, including laboratory assessments and various imaging modalities (e.g. CT, MRI, scintigraphy and EUS) for patients with multiple endocrine neoplasia type 1 (MEN1). Routine screening is proposed to detect and localize neuroendocrine manifestations as early as possible. The goal is timely intervention to improve quality of life and to increase life expectancy by preventing the development of life-threatening hormonal syndromes and/or metastatic disease. In recent years, some studies compared different and new imaging methods regarding their sensitivity and utility in MEN1 patients. This present article reviews the proposed diagnostic tools for MEN1 screening as well as potential future perspectives.

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.

Catching the Zebra: Clinical Pearls and Pitfalls for the Successful Diagnosis of Zollinger-Ellison Syndrome

Zollinger-Ellison syndrome (ZES) results from an ectopic gastrin-secreting tumor leading to peptic ulcer disease, reflux, and chronic diarrhea. While early recognition portends an excellent prognosis with >80% survival at 15 years, symptoms are often nonspecific making the diagnosis difficult to establish. Diagnosis involves a series of tests, including fasting gastrin, gastric pH, chromogranin A, and secretin stimulation. Performing these tests in the correct sequence and at the proper time is essential to avoid inaccurate results. Tumor localization is equally nuanced. Although providers have classically used ¹¹¹indium-radiolabeled octreotide with somatostatin receptor scintigraphy to evaluate tumor size and metastases, recent studies have shown superior results with newer imaging modalities. In particular, ⁶⁸gallium (⁶⁸Ga)-labeled somatostatin radiotracers (i.e., ⁶⁸Ga-DOTATOC, ⁶⁸Ga-DOTANOC and ⁶⁸Ga-DOTATATE) used with positron emission tomography/computed tomography can provide excellent results. Endoscopic ultrasound is another useful modality, particularly in patients with ZES in the setting of multiple endocrine neoplasia type 1. This review aims to provide clinicians with an overview of ZES with a focus on both clinical presentation and the proper utilization of the various biochemical and imaging tests available.

Endocrine neoplasms in familial syndromes of hyperparathyroidism

Familial syndromes of hyperparathyroidism, including multiple endocrine neoplasia type 1 (MEN1), multiple endocrine neoplasia type 2A (MEN2A), and the hyperparathyroidism-jaw tumor (HPT-JT), comprise 2-5% of primary hyperparathyroidism cases. Familial syndromes of hyperparathyroidism are also associated with a range of endocrine and nonendocrine tumors, including potential malignancies. Complications of the associated neoplasms are the major causes of morbidities and mortalities in these familial syndromes, e.g., parathyroid carcinoma in HPT-JT syndrome; thymic, bronchial, and enteropancreatic neuroendocrine tumors in MEN1; and medullary thyroid cancer and pheochromocytoma in MEN2A. Because of the different underlying mechanisms of neoplasia, these familial tumors may have different characteristics compared with their sporadic counterparts. Large-scale clinical trials are frequently lacking due to the rarity of these diseases. With technological advances and the development of new medications, the natural history, diagnosis, and management of these syndromes are also evolving. In this article, we summarize the recent knowledge on endocrine neoplasms in three familial hyperparathyroidism syndromes, with an emphasis on disease characteristics, molecular pathogenesis, recent developments in biochemical and radiological evaluation, and expert opinions on surgical and medical therapies. Because these familial hyperparathyroidism syndromes are associated with a wide variety of tumors in different organs, this review is focused on those endocrine neoplasms with malignant potential.

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.

Hereditary hyperparathyroidism--a consensus report of the European Society of Endocrine Surgeons (ESES)

BACKGROUND

Hereditary hyperparathyroidism has been reported to occur in 5-10 % of cases of primary hyperparathyroidism in the context of multiple endocrine neoplasia (MEN) types 1, 2A and 4; hyperparathyroidism-jaw tumour (HPT-JT); familial isolated hyperparathyroidism (FIHPT); familial hypocalciuric hypercalcaemia (FHH); neonatal severe hyperparathyroidism (NSHPT) and autosomal dominant moderate hyperparathyroidism (ADMH). This paper aims to review the controversies in the main genetic, clinical and pathological features and surgical management of hereditary hyperparathyroidism.

METHODS

A peer review literature analysis on hereditary hyperparathyroidism was carried out and analyzed in an evidence-based perspective. Results were discussed at the 2015 Workshop of the European Society of Endocrine Surgeons devoted to hyperparathyroidism due to multiple gland disease.

RESULTS

Literature reports scarcity of prospective randomized studies; thus, a low level of evidence may be achieved.

CONCLUSIONS

Hereditary hyperparathyroidism typically presents at an earlier age than the sporadic variants. Gene penetrance and expressivity varies. Parathyroid multiple gland involvement is common, but in some variants, it may occur metachronously often with long disease-free intervals, simulating a single-gland involvement. Bilateral neck exploration with subtotal parathyroidectomy or total parathyroidectomy + autotransplantation should be performed, especially in MEN 1, in order to decrease the persistent and recurrent hyperparathyroidism rates; in some variants (MEN 2A, HPT-JT), limited parathyroidectomy can achieve long-term normocalcemia. In FHH, surgery is contraindicated; in NSHPT, urgent total parathyroidectomy is required. In FIHPT, MEN 4 and ADMH, a tailored case-specific approach is recommended.

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: Genetics and Clinical Management

Early diagnosis of multiple endocrine neoplasia (MEN) syndromes is critical for optimal clinical outcomes; before the MEN syndromes can be diagnosed, they must be suspected. Genetic testing for germline alterations in both the MEN type 1 (MEN1) gene and RET proto-oncogene is crucial to identifying those at risk in affected kindreds and directing timely surveillance and surgical therapy to those at greatest risk of potentially life-threatening neoplasia. Pancreatic, thymic, and bronchial neuroendocrine tumors are the leading cause of death in patients with MEN1 and should be aggressively considered by at least biannual computed tomography imaging.