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

Childhood Multiple Endocrine Neoplasia (MEN) Syndromes: Genetics, Clinical Heterogeneity and Modifying Genes

Multiple endocrine neoplasia (MEN) syndromes are part of a spectrum of clinically well-defined tumor syndromes ultimately characterized by histologically similar tumors arising in patients and families with mutations in one of the following four genes: MEN1, RET, CDKN1B, and MAX. The high level of genetic and phenotypic heterogeneity has been linked to phenocopies and modifying genes, as well as unknown mechanisms that might be investigated in the future based on preclinical and translational considerations. MEN1, also known as Wermer's syndrome (OMIM *131100), is an autosomal dominant syndrome codifying for the most frequent MEN syndrome showing high penetrance due to mutations in the MEN1 gene; nevertheless, clinical manifestations vary among patients in terms of tumor localization, age of onset, and clinical aggressiveness/severity, even within the same families. This has been linked to the effect of modifying genes, as described in the review. MEN 2-2b-4 and 5 also show remarkable clinical heterogeneity. The traditional view of genetically predisposing monogenic or multifactorial disorders is no longer valid, and mandates a change in scientific focus. Phenotypes are indeed rarely consistent across genetic backgrounds and environments. In the future, understanding factors and genetic variants that control cellular functions and the expression of disease genes should provide insights into fundamental disease processes, providing implications for counseling and therapeutic and prophylactic possibilities.

Insulinoma Unmasked: A Continuous Glucose Monitoring-Fueled Journey

Insulinomas are rare functional neuroendocrine tumors that are usually indolent and small. Due to their rarity, there is often a delay in disease recognition and diagnosis, and small tumor size makes their localization challenging. Glucose monitoring and dietary modification with or without pharmacotherapy are crucial during diagnostics, and surgery is the only definite treatment. Continuous glucose monitoring (CGM) systems can be a valuable tool in managing insulinoma patients. We present three patients with confirmed endogenous hyperinsulinemic hypoglycemia undergoing tumor localization, medical treatment, and surgery while wearing a CGM system. By accurately depicting glucose fluctuations, CGM can help prevent hypoglycemia, decrease hypoglycemia unawareness, track hypoglycemia frequency, aid in medical therapy dose titration, and confirm a cure after surgery.

[Primary hyperparathyroidism: From diagnosis to treatment]

Primary hyperparathyroidism (PHPT) is the leading cause of hypercalcemia. It is secondary to hypersecretion of parathyroid hormone (PTH) by the parathyroid glands. Today, PHTP is asymptomatic in 80-90% of cases. Its repercussions are mainly renal (nephrolithiasis, nephrocalcinosis, decline in renal function) and skeletal (osteoporosis, fractures), and should be systematically investigated. Diagnosis is only biological, and in its classic form relies on the association of hypercalcemia, inappropriate PTH (normal or elevated) and hypercalciuria. Diagnosis of normocalcemic forms, where only PTH is elevated, requires elimination of secondary hyperparathyroidism and confirmation of elevated PTH on two consecutive samples, over a 3 to 6 months period. Imaging evaluation, which combines neck ultrasound with scintigraphy or 18F-choline PET/CT, is of interest only if surgery is indicated. Surgical management of the hyperfunctioning parathyroid gland(s) is the only curative treatment for HPTP. Medical management concerns patients for whom surgery is not indicated, who present a surgical contraindication or who refuse surgery. The diagnosis of HPTP warrants contact with an endocrinologist to ensure its management.

Agonists, Antagonists and Receptors of Somatostatin: Pathophysiological and Therapeutical Implications in Neoplasias

Somatostatin is a peptide that plays a variety of roles such as neurotransmitter and endocrine regulator; its actions as a cell regulator in various tissues of the human body are represented mainly by inhibitory effects, and it shows potent activity despite its physiological low concentrations. Somatostatin binds to specific receptors, called somatostatin receptors (SSTRs), which have different tissue distributions and associated signaling pathways. The expression of SSTRs can be altered in various conditions, including tumors; therefore, they can be used as biomarkers for cancer cell susceptibility to certain pharmacological agents and can provide prognostic information regarding disease evolution. Moreover, based on the affinity of somatostatin analogs for the different types of SSTRs, the therapeutic range includes conditions such as tumors, acromegaly, post-prandial hypotension, hyperinsulinism, and many more. On the other hand, a number of somatostatin antagonists may prove useful in certain medical settings, based on their differential affinity for SSTRs. The aim of this review is to present in detail the principal characteristics of all five SSTRs and to provide an overview of the associated therapeutic potential in neoplasias.

Familial states of primary hyperparathyroidism: an update

BACKGROUND

Familial primary hyperparathyroidism (PHPT) includes syndromic and non-syndromic disorders. The former are characterized by the occurrence of PHPT in association with extra-parathyroid manifestations and includes multiple endocrine neoplasia (MEN) types 1, 2, and 4 syndromes, and hyperparathyroidism-jaw tumor (HPT-JT). The latter consists of familial hypocalciuric hypercalcemia (FHH) types 1, 2 and 3, neonatal severe primary hyperparathyroidism (NSHPT), and familial isolated primary hyperparathyroidism (FIHP). The familial forms of PHPT show different levels of PHPT penetrance, developing earlier and with multiglandular involvement compared to sporadic counterpart. All these diseases exhibit Mendelian inheritance patterns, and for most of them, the genes responsible have been identified. DNA testing for predisposing mutations is helpful in index cases or in individuals with a high suspicion of the disease. Early recognition of hereditary disorders of PHPT is of great importance for the best clinical and surgical approach. Genetic testing is useful in routine clinical practice because it will also involve appropriate screening for extra-parathyroidal manifestations related to the syndrome as well as the identification of asymptomatic carriers of the mutation.

PURPOSE

The aim of the review is to discuss the current knowledge on the clinical and genetic profile of these disorders along with the importance of genetic testing in clinical practice.

Multiple Endocrine Neoplasia Type 1, Type 2A, and Type 2B

Multiple endocrine neoplasia type 1 is a rare genetic neuroendocrine syndrome caused by over 1500 different germline mutations. It can cause 20 different endocrine tumors affecting primarily the parathyroid glands, gastroenteropancreatic tract, and the anterior pituitary gland. Multiple endocrine neoplasia type 2A (MEN2A) and Multiple endocrine neoplasia type 2B (MEN2B) are autosomal dominant genetic syndromes because of a germline variant in the 'rearranged during transfection' (RET) proto-oncogene. There are common RET mutations causing receptor hyperactivation and induction of downstream signals that cause oncogenesis. Common conditions with MEN2A are medullary thyroid cancer (MTC), pheochromocytoma, and primary hyperparathyroidism. Common conditions with MEN2B include MTC, pheochromocytomas, and benign ganglioneuromas.

Novel classification of gastric polyps: The good, the bad and the ugly

Gastric polyps (GPs) are increasingly common. On upper endoscopy, they should be examined with white light and occasionally chromoendoscopy, and their morphology classified according to the Paris classification. Most GPs have a typical endoscopic appearance and can be associated with diseases like Helicobacter pylori infection. Histological examination is necessary for an accurate diagnosis. While most polyps are non-neoplastic and do not require treatment, some carry a risk of malignancy or are already malignant. Therefore, understanding the diagnosis, classification, and management of GPs is crucial for patient prognostication. Our new classification categorizes GPs into "good", "bad", and "ugly" based on their likelihood of becoming malignant. We aim to provide descriptions of the endoscopic appearance, pathology, treatment, and follow-up for different GPs, as well as clinical management flowcharts.

Prospective Genetic Screening in Multiple Endocrine Neoplasia Syndromes

Multiple endocrine neoplasia syndromes are a rare but potentially fatal pathology due to the lack of early diagnosis. We have performed a narrative review of the medical literature, summarizing the main clinical concepts useful in current clinical practice, showing the importance of screening and early diagnosis during childhood.

Unlocking the Genetic Secrets of Acromegaly: Exploring the Role of Genetics in a Rare Disorder

Acromegaly is a rare endocrine disorder characterized by the excessive production of growth hormone (GH) in adulthood. Currently, it is understood that certain pituitary neuroendocrine tumors (PitNETs) exhibit a hereditary predisposition. These tumors' genetic patterns fall into two categories: isolated and syndromic tumors. The isolated forms are characterized by molecular defects that predispose exclusively to PitNETs, including familial isolated pituitary adenomas (FIPAs) and sporadic genetic defects not characterized by hereditary predisposition. All the categories involve either germline or somatic mutations, or both, each associated with varying levels of penetrance and different phenotypes. This highlights the importance of genetic testing and the need for a more comprehensive view of the whole disease. Despite the availability of multiple treatment options, diagnosis often occurs after several years, and management is still difficult. Early detection and intervention are crucial for preventing complications and enhancing the quality of life for affected individuals. This review aims to elucidate the molecular, clinical, and histological characteristics of GH-secreting PitNETs, providing insights into their prevalence, treatment nuances, and the benefits of genetic testing for each type of genetic disorder associated with acromegaly.

Complex Primary Hyperparathyroidism: Hereditary and Recurrent Disease

Primary hyperparathyroidism can be sporadic or part of a genetic syndrome, such as MEN1 or HPT-JT. Diagnosis of hereditary HPT requires a thorough history and physical. Parathyroidectomy is curative with greater than 95% success. However, some patients have persistent or recurrent disease requiring reoperation. Reoperative parathyroidectomy is technically challenging, and localizing the pathologic gland can difficult. Patients needing reoperation should undergo evaluation by a high-volume surgeon. Care should be taken to obtain all of the preoperative workup and operative note from the initial surgery. Radioguided parathyroidectomy can be safely and effectively performed in patients with hereditary HPT or undergoing reoperative surgery.

A Rare Case of Ectopic Adrenocorticotropic Hormone Syndrome (EAS) in an Adolescent Girl With a Thymic Neuroendocrine Tumour

In adults, Cushing's syndrome (CS) caused by tumours that produce adrenocorticotropic hormone (ACTH) outside of the pituitary gland is quite prevalent. However, it is uncommon in children and teenagers. Ectopic ACTH syndrome (EAS) is a rare occurrence in young children, accounting for less than 1% of cases. Nevertheless, when it does occur, it tends to be a severe condition due to the profound hypercortisolism that can occur independently of the tumour. Consequently, EAS should be regarded as a critical endocrine emergency, necessitating prompt action in terms of diagnostic procedures and therapeutic interventions. A 14-year-old White female from the United Kingdom (UK) presented with a two-week history of hands and feet swelling, accompanied by a non-itchy rash on the face, back, and chest for one week. Initial investigations revealed hypokalemic alkalosis, hyperglycaemia, elevated serum and 24-hour urinary cortisol, and high ACTH level. Further investigations confirmed EAS, and to find out the primary tumour location, a contrast-enhanced thoracic CT scan was done and identified a 5x3 cm mass with enhanced thymic shadow. Increased radioactivity uptake in the left upper chest along with widespread GAD-avid metastatic disease unveiled by Gallium-DOTA-TATE PET scan. An abdominal MRI, detecting multiple liver deposits, prompted a liver biopsy, revealing a malignant tumour with neuroendocrine differentiation. The patient was diagnosed with EAS with a primary neuroendocrine tumour of the thymus and metastasis. This case underscores the significance of considering EAS in patients with a diagnosis of CS, especially in young individuals with no known risk factors.

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.

Giant parathyroid adenoma and hungry bone syndrome in MEN1 syndrome: A case report

An 18-year-old male with multiple endocrine neoplasm type 1 (MEN1) syndrome presented with hyperparathyroidism. Parathyroidectomy was performed. Patient complained of bone pain afterwards, multiple imaging modalities revealed features of osteitis fibrosa cystica and biochemical profile showed features of hungry bone syndrome. Incidental suspicious pancreatic lesion was initially revealed by 18F-FDG PET/CT scan while MRI further characterized the possibility of insulinoma. Ultimately, the patient was diagnosed of MEN1 syndrome by genetic test. This case report demonstrates the utilization of various imaging modalities such as ultrasound, Tc99m-sestamibi parathyroid scintigraphy, bone scintigraphy, CT, PET/CT and MRI, which leads to ultimately the diagnosis of MEN1 syndrome.

Menin signaling and therapeutic targeting in breast cancer

To date, mounting evidence have shown that patients with multiple endocrine neoplasia type 1 (MEN1) may face an increased risk for breast carcinogenesis. The product of the MEN1 gene, menin, was also indicated to be an important regulator in breast cancer signaling network. Menin directly interacts with MLL, EZH2, JunD, NF-κB, PPARγ, VDR, Smad3, β-catenin and ERα to modulate gene transcriptions leading to cell proliferation inhibition. Moreover, interaction of menin-FANCD2 contributes to the enhancement of BRCA1-mediated DNA repair mechanism. Ectopic expression of menin causes Bax-, Bak- and Caspase-8-dependent apoptosis. However, despite numbers of menin inhibitors were exploited in other cancers, data on the usage of menin inhibitors in breast cancer treatment remain limited. In this review, we focused on the menin associated signaling pathways and gene transcription regulations, with the aim of elucidating its molecular mechanisms and of guiding the development of novel menin targeted drugs in breast cancer therapy.

The risk of concurrent malignancies in patients with multiple endocrine neoplasia type 1: insights into clinical characteristics of those with multiple endocrine neoplasia type 1

OBJECTIVE

Summarize and analyze the characteristics of patients with Multiple Endocrine Neoplasia type 1 (MEN-1) who were diagnosed with malignant tumors that do not belong to MEN-1 components.

METHODS

Clinical data from patients with MEN-1 who visited Peking Union Medical College Hospital between April 2012 and April 2022 were collected. We compared the clinical characteristics of patients with malignant tumors outside of their MEN-1 components to those without additional tumors. MEN-1 gene testing was performed on most of these patients using Sanger sequencing, whole-exome sequencing, or MLPA.

RESULTS

A total of 221 MEN-1 patients were diagnosed, of which 23 (10.40%) were found to have malignant tumors that did not belong to MEN-1 components, including papillary thyroid carcinoma (PTC) (4.52%), breast cancer (1.81%), urologic neoplasms (1.35%), primary hepatic carcinoma (PCC) (0.09%), meningeal sarcoma (0.05%), glioblastoma (0.05%), cervical cancer (0.05%), and lung carcinoma (0.05%). MEN-1 gene mutations were identified in 11 patients, including missense mutations, frameshift mutations, and splice mutations. The prevalence of each endocrine neoplasm, particularly gastroenteropancreatic neuroendocrine tumor, was higher in MEN-1 patients with other malignant tumors compared to MEN-1 patients without malignant tumors.

CONCLUSION

Our retrospective study revealed a higher incidence of non-MEN-1 component malignant tumors in MEN-1 patients, especially breast cancer, PTC, and urologic neoplasms. These patients also exhibit more severe clinical phenotypes of MEN-1.

[30 years of prophylactic thyroidectomy for hereditary medullary thyroid cancer : A milestone in translational medicine]

Medullary thyroid cancer (MTC) is the most frequent manifestation of multiple endocrine neoplasia type 2 (MEN2) that determines the oncological outcome. Germline mutations in the rearranged during transfection (RET) protooncogene, a tumor suppressor gene on chromosome 10q11.2, were identified 30 years ago as the genetic basis of MEN2 and published in 1993 and 1994. These seminal findings gave rise to the concept of prophylactic thyroidectomy for asymptomatic gene mutation carriers based on a positive RET gene test, which has become the standard of care ever since. Clinical genetic investigations showed genotype-phenotype correlations with respect to the individual gene mutation regarding the penetrance and onset of MTC and to a lesser extent also with respect to the other components of MEN2, pheochromocytoma and primary hyperparathyroidism. From this a clinically relevant risk stratification could be derived. Initially, the optimal timing of prophylactic thyroidectomy was primarily based on the RET genotype alone, which was not sufficient for a precise age recommendation and subsequently required additional consideration of calcitonin serum levels for fine tuning. Calcitonin levels first show the risk of lymph node metastasis when they exceed the upper normal limit of the assay independent of carrier age and RET mutation. Routine calcitonin screening of patients with nodular thyroid disease, screening of families on identification of MEN2 index patients, and pre-emptive thyroidectomy in carriers of gene mutations with normal calcitonin levels have led to the fact that nowadays, 30 years after the first description of the gene mutations causing the disease, the life-threatening hereditary MTC has become curable: a shining example for the success of translational transnational medical research for the benefit of patients.

The diverging role of O-GlcNAc transferase in corticotroph and somatotroph adenomas

PURPOSE

Molecular mechanisms involved in the pathogenesis and tumor progression of pituitary adenomas (PA) remain incompletely understood. Corticotroph and somatotroph PA are associated with a high clinical burden, and despite improved surgical outcomes and medical treatment options, they sometimes require multiple surgeries and radiation. Preliminary data suggested a role for O-GlcNAc Transferase (OGT), the enzyme responsible for the O-GlcNAcylation of proteins. O-GlcNAcylation and OGT have been found elevated in other types of tumors.

METHODS

We evaluated 60 functioning and nonfunctioning PA (NFPA) from operated patients and postmortem normal and tumoral pituitary tissue by immunohistochemistry. We performed transcriptomic analyses to explore the relevance of the O-GlcNAc Transferase (OGT) in PAs. We detected OGT in immunobiological analysis and define its level in PA tissue in patients.

RESULTS

OGT was strongly associated with PA hormone secretory capacity in functioning PA and with tumor growth in NFPAs. In NFPAs, OGT was positively associated with tumor size but not with cavernous sinus invasion (Knosp grading). In GH-secreting PA, OGT expression was negatively correlated with circulating Insulin-like Growth Factor 1 level. In adrenocorticotropic hormone (ACTH)-secreting PA, OGT expression was positively associated with circulating ACTH levels. OGT did not correlate with tumor size in secreting PAs. OGT levels were higher in gonadotroph PA compared to normal glands.

CONCLUSION

O-GlcNAcylation can be downregulated in non-cancerous tumors such as GH-secreting adenomas. Future studies are warranted to elucidate the role of OGT in the pathogenesis of PAs.

WC, Medina B. VL, Romero-Rojas AE, Vieda-Celemin I, Avila-Moya JA, Baron-Cardona JA, Bravo-Patiño JP, Torres-Zambrano OS, Maya LFF. Case report: Comprehensive follow-up of a Colombian family carrying a novel MEN1 variant linked to a rare ACTH-producing pancreatic neuroendocrine carcinoma

Background

Multiple Endocrine Neoplasia type 1 (MEN1) is an autosomal dominant disorder marked by pathogenic variants in the MEN1 tumor suppressor gene, leading to tumors in the parathyroid glands, pancreas, and pituitary. The occurrence of ACTH-producing pancreatic neuroendocrine carcinoma is exceedingly rare in MEN1.

Case presentation

This report details a Colombian family harboring a novel MEN1 variant identified through genetic screening initiated by the index case. Affected family members exhibited primary hyperparathyroidism (PHPT) symptoms from their 20s to 50s. Uniquely, the index case developed an ACTH-secreting pancreatic neuroendocrine carcinoma, a rarity in MEN1 syndromes. Proactive screening enabled the early detection of pituitary neuroendocrine tumors (PitNETs) as microadenomas in two carriers, with subsequent surgical or pharmacological intervention based on the clinical presentation.

Conclusion

Our findings underscore the significance of cascade screening in facilitating the early diagnosis and individualized treatment of MEN1, contributing to better patient outcomes. Additionally, this study brings to light a novel presentation of ACTH-producing pancreatic neuroendocrine carcinoma within the MEN1 spectrum, expanding our understanding of the disease's manifestations.

Early detection of multiple endocrine neoplasia type 1: A case report

BACKGROUND

Multiple endocrine neoplasias (MENs) are a group of hereditary diseases involving multiple endocrine glands, and their prevalence is low. MEN type 1 (MEN1) has diverse clinical manifestations, mainly involving the parathyroid glands, gastrointestinal tract, pancreas and pituitary gland, making it easy to miss the clinical diagnosis.

CASE SUMMARY

We present the case of a patient in whom MEN1 was detected early. A middle-aged male with recurrent abdominal pain and diarrhea was admitted to the hospital. Blood tests at admission revealed hypercalcemia and hypophosphatemia, and emission computed tomography of the parathyroid glands revealed a hyperfunctioning parathyroid lesion. Gastroscopy findings suggested a duodenal bulge and ulceration. Ultrasound endoscopy revealed a hypoechoic lesion in the duodenal bulb. Further blood tests revealed elevated levels of serum gastrin. Surgery was performed, and pathological analysis of the surgical specimens revealed a parathyroid adenoma after parathyroidectomy and a neuroendocrine tumor after duodenal bulbectomy. The time from onset to the definitive diagnosis of MEN1 was only approximately 1 year.

CONCLUSION

For patients who present with gastrointestinal symptoms accompanied by hypercalcemia and hypophosphatemia, clinicians need to be alert to the possibility of MEN1.

Treatment, Prognostic Markers, and Survival in Thymic Neuroendocrine Tumors, with Special Reference to Temozolomide-Based Chemotherapy

BACKGROUND

Thymic neuroendocrine tumors (Th-NETs) are rare and aggressive, with a scarcity of research on predicting patient prognosis. Our study aimed to assess the impact of prognostic markers and temozolomide (TMZ)-based chemotherapy on survival in Th-NETs.

METHODS

We retrospectively reviewed the medical records of patients diagnosed with Th-NETs between 2013 and 2023 at our institution. We collected clinicopathological data, including tumor pathological grading, staging, serum concentrations of neuron-specific enolase (NSE) and pro-gastrin-releasing peptide, levels of inflammatory factors, and expression of oxygen 6-methylguanine-DNA methyltransferase (MGMT). Treatment details (such as surgery and chemotherapy) and survival outcomes were also documented.

RESULTS

A total of 32 patients were included in our study after excluding those without complete available information. The median progression-free survival (PFS) was 12.5 months (95%CI, 8-16 months) for 19 patients who received TMZ-based chemotherapy. Twenty-one patients underwent surgery as the primary treatment, demonstrating a median disease-free survival (DFS) of 51.0 months. The inflammatory factor neutrophil-to-lymphocyte ratio (NLR) was an independent prognostic indicator of DFS in postoperative patients and PFS in TMZ-treated patients. The overall 3-, 5-, and 10-year survival rates were 86.6%, 69.5%, and 33.8%, respectively. Ki67 level exceeding 10% (p = 0.048) and absence of surgical resection (p = 0.003) were significantly associated with worse overall survival (OS).

CONCLUSION

Surgical treatment was currently the primary method for treating Th-NETs, and postoperative adjuvant therapy was an essential consideration for specific patient cohorts. Despite widespread positive MGMT expression, TMZ-based chemotherapy showed promise. Some potential prognostic biomarkers such as NLR and NSE need more attention.

Germline Testing Identifies Pathogenic/Likely Pathogenic Variants in Patients with Pancreatic Neuroendocrine Tumors

Ten percent of pancreatic neuroendocrine tumors (pNET) are related to inherited syndromes (MEN1, MEN4, VHL, NF1, and TSC). Growing evidence suggests that clinically sporadic pNETs can also harbor germline pathogenic variants. In this study, we report the prevalence of pathologic/likely pathologic (P/LP) germline variants in a high-risk cohort and an unselected cohort. We collected clinical data of patients with pNETs seen at MD Anderson Cancer Center and Johns Hopkins Hospital. The high-risk cohort included (n = 132) patients seen at MD Anderson Cancer Center who underwent germline testing for high-risk criteria (early onset, personal or family history of cancer, and syndromic features) between 2013 and 2019. The unselected cohort included (n = 106) patients seen at Johns Hopkins Hospital who underwent germline testing following their diagnosis of pNETs between 2020 and 2022. In the high-risk cohort (n = 132), 33% (n = 44) had P/LP variants. The majority of the patients had P/LP variants in MEN1 56% (n = 25), followed by DNA repair pathways 18% (n = 8), and 7% (n = 3) in MSH2 (Lynch syndrome). Patients with P/LP were younger (45 vs. 50 years; P = 0.002). In the unselected cohort (n = 106), 21% (n = 22) had P/LP. The majority were noted in DNA repair pathways 40% (n = 9) and MEN1 36% (n = 8). Multifocal tumors correlated with the presence of P/LP (P = 0.0035). MEN1 germline P/LP variants correlated with younger age (40 vs. 56 years; P = 0.0012), presence of multifocal tumors (P < 0.0001), and World Health Organization grade 1 histology (P = 0.0078). P/LP variants are prevalent in patients with clinically sporadic pNET irrespective of high-risk features. The findings support upfront universal germline testing in all patients with pNET. Prevention Relevance: Here, we present germline data from the largest reported cohort of patients with pNET (n = 238), comprising both a high-risk cohort and an unselected cohort. In both cohorts, we identify a high number of P/LPs, including those in the DNA repair pathway. Our findings support universal germline testing in patients with pNET.

Safety and Efficacy of 177 Lu-DOTATATE in Children and Young Adult Population : A Single-Center Experience

PURPOSE

This single-center retrospective study explores the safety and efficacy of 177 Lu-DOTATATE in children and young adult population with metastatic/inoperable neuroendocrine tumors (NETs).

PATIENTS AND METHODS

This study is a retrospective analysis of all children and young adult patients (≤29 years) with advanced inoperable/metastatic epithelial or nonepithelial NETs who were administered a median of 4 cycles of 177 Lu-DOTATATE therapy and low-dose oral capecitabine as a radiosensitizer every 8-12 weeks, except 2 patients who received CAPTEM chemotherapy. The radiological response was assessed using RECIST 1.1 on interim and end-of-treatment 68 Ga-DOTANOC PET/CT. The primary endpoint was objective response rate, whereas disease control rate, toxicity profile, progression-free survival, and overall survival were secondary endpoints.

RESULTS

Nineteen biopsy-proven NET patients (median age, 22 ± 10 years) with 8 of them adolescents (10-18 years) and the remaining young adults (19-29 years) were included. Fourteen patients had gastroenteropancreatic neuroendocrine tumor (pancreas being most common primary site), whereas the rest had non-gastroenteropancreatic neuroendocrine tumor. A total of 65 cycles of 177 Lu-DOTATATE (range, 1-6 cycles) were administered with a median cumulative activity of 600 mCi (range, 100-1000 mCi). The objective response rate and disease control rate were 41% and 94%, respectively. Grade 1 and 2 adverse events were observed in 14 (74%) and 5 (26%) of 19 patients, respectively. In a total of 8 events (42%), 4 events each of disease progression and death occurred during a median follow-up of 80.1 months with an estimated 5-year progression-free survival and overall survival of 54% (95% confidence interval, 30-78) and 63% (95% confidence interval, 39-87), respectively.

CONCLUSIONS

177 Lu-DOTATATE appears safe and effective in children and young adults with metastatic/inoperable NETs. Large prospective trials are required to validate these results.

A Cohort Study of CNS Tumors in Multiple Endocrine Neoplasia Type 1

PURPOSE

Multiple endocrine neoplasia type 1 (MEN1) is thought to increase the risk of meningioma and ependymoma. Thus, we aimed to describe the frequency, incidence, and specific clinical and histological features of central nervous system (CNS) tumors in the MEN1 population (except pituitary tumors).

EXPERIMENTAL DESIGN

The study population included patients harboring CNS tumors diagnosed with MEN1 syndrome after 1990 and followed up in the French MEN1 national cohort. The standardized incidence ratio (SIR) was calculated based on the French Gironde CNS Tumor Registry. Genomic analyses were performed on somatic DNA from seven CNS tumors, including meningiomas and ependymomas from patients with MEN1, and then on 50 sporadic meningiomas and ependymomas.

RESULTS

A total of 29 CNS tumors were found among the 1,498 symptomatic patients (2%; incidence = 47.4/100,000 person-years; SIR = 4.5), including 12 meningiomas (0.8%; incidence = 16.2/100,000; SIR = 2.5), 8 ependymomas (0.5%; incidence = 10.8/100,000; SIR = 17.6), 5 astrocytomas (0.3%; incidence = 6.7/100,000; SIR = 5.8), and 4 schwannomas (0.3%; incidence = 5.4/100,000; SIR = 12.7). Meningiomas in patients with MEN1 were benign, mostly meningothelial, with 11 years earlier onset compared with the sporadic population and an F/M ratio of 1/1. Spinal and cranial ependymomas were mostly classified as World Health Organization grade 2. A biallelic MEN1 inactivation was observed in 4/5 ependymomas and 1/2 meningiomas from patients with MEN1, whereas MEN1 deletion in one allele was present in 3/41 and 0/9 sporadic meningiomas and ependymomas, respectively.

CONCLUSIONS

The incidence of each CNS tumor was higher in the MEN1 population than in the French general population. Meningiomas and ependymomas should be considered part of the MEN1 syndrome, but somatic molecular data are missing to conclude for astrocytomas and schwannomas.

Imaging Update for Hereditary Abdominopelvic Neuroendocrine Neoplasms

ABSTRACT

Neuroendocrine neoplasms have shown a linear increase in incidence and prevalence in recent decades, primarily due to improved cross-sectional imaging, expanded use of endoscopic procedures, and advanced genetic analysis. However, diagnosis of hereditary neuroendocrine tumors is still challenging because of heterogeneity in their presentation, the variety of tumor locations, and multiple associated syndromes. Radiologists should be familiar with the spectrum of these tumors and associated hereditary syndromes. Furthermore, as the assessment of multiple tumor elements such as morphology, biochemical markers, and presence of metastatic disease are essential for the treatment plan, conventional anatomic and functional imaging methods are fundamental in managing and surveilling these cases. Our article illustrates the role of different cross-sectional imaging modalities in diagnosing and managing various hereditary abdominopelvic neuroendocrine tumors.

A novel likely pathogenetic variant p.(Cys235Arg) of the MEN1 gene in multiple endocrine neoplasia type 1 with multifocal glucagonomas

PURPOSE

Multiple endocrine neoplasia type 1 (MEN1) is a hereditary endocrine syndrome caused by pathogenic variants in MEN1 tumor suppressor gene. Diagnosis is commonly based on clinical criteria and confirmed by genetic testing. The objective of the present study was to report on a MEN1 case characterized by multiple pancreatic glucagonomas, with particular concern on the possible predisposing genetic defects.

METHODS

While conducting an extensive review of the most recent scientific evidence on the unusual glucagonoma familial forms, we analyzed the MEN1 gene in a 35-year-old female with MEN1, as well as her son and daughter, using Sanger and next-generation sequencing (NGS) approaches. We additionally explored the functional and structural consequences of the identified variant using in silico analyses.

RESULTS

NGS did not show any known pathogenic variant in the tested regions. However, a new non-conservative variant in exon 4 of MEN1 gene was found in heterozygosity in the patient and in her daughter, resulting in an amino acid substitution from hydrophobic cysteine to hydrophilic arginine at c.703T > C, p.(Cys235Arg). This variant is absent from populations databases and was never reported in full papers: its characteristics, together with the high specificity of the patient's clinical phenotype, pointed toward a possible causative role.

CONCLUSION

Our findings confirm the need for careful genetic analysis of patients with MEN1 and establish a likely pathogenic role for the new p.(Cys235Arg) variant, at least in the rare subset of MEN1 associated with glucagonomas.

Beyond MEN1, When to Think About MEN4? Retrospective Study on 5600 Patients in the French Population and Literature Review

CONTEXT

Germline CDKN1B variants predispose patients to multiple endocrine neoplasia type 4 (MEN4), a rare MEN1-like syndrome, with <100 reported cases since its discovery in 2006. Although CDKN1B mutations are frequently suggested to explain cases of genetically negative MEN1, the prevalence and phenotype of MEN4 patients is poorly known, and genetic counseling is unclear.

OBJECTIVE

To evaluate the prevalence of MEN4 in MEN1-suspected patients and characterize the phenotype of MEN4 patients.

DESIGN

Retrospective observational nationwide study. Narrative review of literature and variant class reassessment.

PATIENTS

We included all adult patients with class 3/4/5 CDKN1B variants identified by the laboratories from the French Oncogenetic Network on Neuroendocrine Tumors network between 2015 and 2022 through germline genetic testing for MEN1 suspicion. After class reassessment, we compared the phenotype of symptomatic patients with class 4/5 CDKN1B variants (ie, with genetically confirmed MEN4 diagnosis) in our series and in literature with 66 matched MEN1 patients from the UMD-MEN1 database.

RESULTS

From 5600 MEN1-suspected patients analyzed, 4 with class 4/5 CDKN1B variant were found (0.07%). They presented with multiple duodenal NET, primary hyperparathyroidism (PHPT) and adrenal nodule, isolated PHPT, PHPT, and pancreatic neuroendocrine tumor. We listed 29 patients with CDKN1B class 4/5 variants from the literature. Compared with matched MEN1 patients, MEN4 patients presented lower NET incidence and older age at PHPT diagnosis.

CONCLUSION

The prevalence of MEN4 is low. PHPT and pituitary adenoma represent the main associated lesions, NETs are rare. Our results suggest a milder and later phenotype than in MEN1. Our observations will help to improve genetic counseling and management of MEN4 families.

Menin Deficiency Induces Autism-Like Behaviors by Regulating Foxg1 Transcription and Participates in Foxg1-Related Encephalopathy

FOXG1 syndrome is a developmental encephalopathy caused by FOXG1 (Forkhead box G1) mutations, resulting in high phenotypic variability. However, the upstream transcriptional regulation of Foxg1 expression remains unclear. This report demonstrates that both deficiency and overexpression of Men1 (protein: menin, a pathogenic gene of MEN1 syndrome known as multiple endocrine neoplasia type 1) lead to autism-like behaviors, such as social defects, increased repetitive behaviors, and cognitive impairments. Multifaceted transcriptome analyses revealed that Foxg1 signaling is predominantly altered in Men1 deficiency mice, through its regulation of the Alpha Thalassemia/Mental Retardation Syndrome X-Linked (Atrx) factor. Atrx recruits menin to bind to the transcriptional start region of Foxg1 and mediates the regulation of Foxg1 expression by H3K4me3 (Trimethylation of histone H3 lysine 4) modification. The deficits observed in menin deficient mice are rescued by the over-expression of Foxg1, leading to normalized spine growth and restoration of hippocampal synaptic plasticity. These findings suggest that menin may have a putative role in the maintenance of Foxg1 expression, highlighting menin signaling as a potential therapeutic target for Foxg1-related encephalopathy.

Management of surgical diseases of Primary Hyperparathyroidism: indications of the United Italian Society of Endocrine Surgery (SIUEC)

A task force of the United Italian society of Endocrine Surgery (SIUEC) was commissioned to review the position statement on diagnostic, therapeutic and health‑care management protocol in parathyroid surgery published in 2014, at the light of new technologies, recent oncological concepts, and tailored approaches. The objective of this publication was to support surgeons with modern rational protocols of treatment that can be shared by health-care professionals, taking into account important clinical, healthcare and therapeutic aspects, as well as potential sequelae and complications. The task force consists of 12 members of the SIUEC highly trained and experienced in thyroid and parathyroid surgery. The main topics concern diagnostic test and localization studies, mode of admission and waiting time, therapeutic pathway (patient preparation for surgery, surgical treatment, postoperative management, management of major complications), hospital discharge and patient information, outpatient care and follow-up, outpatient initial management of patients with pHPT.

Hereditary Syndromes Associated with Pancreatic and Lung Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PanNETs) and lung NETs (LNETs) represent a rare but clinically significant subgroup of neoplasms. While the majority is sporadic, approximately 17% of PanNETs and a subset of LNETs develop in the context of monogenic familial tumor syndromes, especially multiple endocrine neoplasia type 1 (MEN1) syndrome. Other inherited syndromes associated with PanNETs include MEN4, von Hippel-Lindau (VHL) syndrome, neurofibromatosis type 1 (NF1), and tuberous sclerosis complex (TSC). These syndromes are highly penetrant and their clinical manifestations may vary even among members of the same family. They are attributed to genetic mutations involving key molecular pathways regulating cell growth, differentiation, and angiogenesis. Pancreatic NETs in hereditary syndromes are often multiple, develop at a younger age compared to sporadic tumors, and are associated with endocrine and nonendocrine tumors derived from multiple organs. Lung NETs are not as common as PanNETs and are mostly encountered in MEN1 syndrome and include typical and atypical lung carcinoids. Early detection of PanNETs and LNETs related to inherited syndromes is crucial, and specific follow-up protocols need to be employed to optimize diagnosis and management. Genetic screening is recommended in childhood, and diagnostic screening starts often in adolescence, even in asymptomatic mutation carriers. Optimal management and therapeutic decisions should be made in the context of a multidisciplinary team in specialized centers, whereas specific biomarkers aiming to identify patients denoted to follow a more aggressive course need to be developed.

Role of Nutrition in the Management of Patients with Multiple Endocrine Neoplasia Type 1

Multiple endocrine neoplasia type 1 (MEN1) is a rare syndrome caused by inactivating mutations in the MEN1 tumor suppressor gene. The three main clinical manifestations of MEN1 are primary hyperparathyroidism (PHPT), duodenal-pancreatic neuroendocrine tumors (DP-NETs) and anterior pituitary tumors. Endocrine tumors in patients with MEN1 differ from sporadic tumors because of their younger age at onset, common multiple presentations and the different clinical course. MEN1 is characterized by a complex clinical phenotype; thus, patients should be followed by a multidisciplinary team of experts that includes an endocrinologist, a surgeon, a oncologist, a radiotherapist, and not least, a nutritionist. It is important to remember the fundamental role that diet plays as a primary prevention tool, together with a healthy and active lifestyle in preventing osteoporosis/osteopenia and reducing the risk of developing kidney stones due to hypercalciuria, two frequent clinical complications in MEN1 patients. Is very important for MEN1 patients to have an adequate intake of calcium, vitamin D, magnesium and phosphate to maintain good bone health. The intake of foods containing oxalates must also be kept under control because in combination with calcium they concur to form calcium oxalate crystals, increasing the risk of nephrolithiasis. Another aspect to consider is the management of patients with pancreatic neuroendocrine tumors undergoing major surgical resections of the pancreas that can lead to alterations in digestion and absorption mechanisms due to partial or total reduction in pancreatic enzymes such as amylase, lipase, and protease, resulting in malabsorption and malnutrition. Therefore, the nutritionist's aim should be to devise a dietary plan that takes into consideration each single patient, educating them about a healthy and active lifestyle, and accompanying them through various life stages by implementing strategies that can enhance their quality of life.

Syndromic MEN1 parathyroid adenomas consist of both subclonal nodules and clonally independent tumors

Primary hyperparathyroidism with parathyroid tumors is a typical manifestation of Multiple Endocrine Neoplasia Type 1 (MEN1) and is historically termed "primary hyperplasia". Whether these tumors represent a multi-glandular clonal disease or hyperplasia has not been robustly proven so far. Loss of Menin protein expression is associated with inactivation of both alleles and a good surrogate for a MEN1 gene mutation. The cyclin-dependent kinase inhibitor 1B (CDKN1B) gene is mutated in MEN4 and encodes for protein p27 whose expression is poorly studied in the syndromic MEN1 setting.Here, we analyzed histomorphology and protein expression of Menin and p27 in parathyroid adenomas of 25 patients of two independent, well-characterized MEN1 cohorts. The pattern of loss of heterozygosity (LOH) was assessed by fluorescence in situ hybridization (FISH) in one MEN1-associated parathyroid adenoma. Further, next-generation sequencing (NGS) was performed on eleven nodules of four MEN1 patients.Morphologically, the majority of MEN1 adenomas consisted of multiple distinct nodules, in which Menin expression was mostly lost and p27 protein expression reduced. FISH analysis revealed that most nodules exhibited MEN1 loss, with or without the loss of centromere 11. NGS demonstrated both subclonal evolution and the existence of clonally unrelated tumors.Syndromic MEN1 parathyroid adenomas therefore consist of multiple clones with subclones, which supports the current concept of the novel WHO classification of parathyroid tumors (2022). p27 expression was lost in a large fraction of MEN1 parathyroids and must therefore be used with caution in suggesting MEN4.

Consensus guideline for the diagnosis and management of pituitary adenomas in childhood and adolescence: Part 1, general recommendations

Tumours of the anterior part of the pituitary gland represent just 1% of all childhood (aged <15 years) intracranial neoplasms, yet they can confer high morbidity and little evidence and guidance is in place for their management. Between 2014 and 2022, a multidisciplinary expert group systematically developed the first comprehensive clinical practice consensus guideline for children and young people under the age 19 years (hereafter referred to as CYP) presenting with a suspected pituitary adenoma to inform specialist care and improve health outcomes. Through robust literature searches and a Delphi consensus exercise with an international Delphi consensus panel of experts, the available scientific evidence and expert opinions were consolidated into 74 recommendations. Part 1 of this consensus guideline includes 17 pragmatic management recommendations related to clinical care, neuroimaging, visual assessment, histopathology, genetics, pituitary surgery and radiotherapy. While in many aspects the care for CYP is similar to that of adults, key differences exist, particularly in aetiology and presentation. CYP with suspected pituitary adenomas require careful clinical examination, appropriate hormonal work-up, dedicated pituitary imaging and visual assessment. Consideration should be given to the potential for syndromic disease and genetic assessment. Multidisciplinary discussion at both the local and national levels can be key for management. Surgery should be performed in specialist centres. The collection of outcome data on novel modalities of medical treatment, surgical intervention and radiotherapy is essential for optimal future treatment.

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

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

Challenges in genetic screening for inherited endocrinopathy affecting the thyroid, parathyroid and adrenal glands in Singapore

Significant progress has been made in the understand-ing of many human diseases, especially cancers, which has contributed to improved and increased survival. The Human Genome Project and The Cancer Genome Atlas project brought about a new era, with an understanding of inherited diseases at a molecular level, which subsequently facilitated the option of precision medicine. Precision medicine has helped tailor treatment decisions at an individual level, for instance in terms of surgical treatments or targeted therapies in advanced diseases. Despite the increasing advances in genetic-lead precision medicine, this has not translated into increasing uptake among patients. Reasons for this may be potential knowledge gaps among clinicians; on reasons for poor uptake of genetic testing such as for cultural, religious or personal beliefs; and on financial implications such as lack of support from insurance companies. In this review, we look at the current scenario of genetic screening for common inherited endocrine conditions affecting the thyroid, parathyroid and adrenal glands in Singapore, and the implications associated with it.

Mixed-Lineage Leukaemia Gene Regulates Glucose-Sensitive Gene Expression and Insulin Secretion in Pancreatic Beta Cells

The escalating prevalence of diabetes mellitus underscores the need for a comprehensive understanding of pancreatic beta cell function. Interest in glucose effectiveness has prompted the exploration of novel regulatory factors. The myeloid/lymphoid or mixed-lineage leukaemia gene (MLL) is widely recognised for its role in leukemogenesis and nuclear regulatory mechanisms through its histone methyltransferase activity in active chromatin. However, its function within pancreatic endocrine tissues remains elusive. Herein, we unveil a novel role of MLL in glucose metabolism and insulin secretion. MLL knockdown in βHC-9 pancreatic beta cells diminished insulin secretion in response to glucose loading, paralleled by the downregulation of the glucose-sensitive genes SLC2a1 and SLC2a2. Similar observations were made in MLL heterozygous knockout mice (MLL+/-), which exhibited impaired glucose tolerance and reduced insulin secretion without morphological anomalies in pancreatic endocrine cells. The reduction in insulin secretion was independent of changes in beta cell mass or insulin granule morphology, suggesting the regulatory role of MLL in glucose-sensitive gene expression. The current results suggest that MLL interacts with circadian-related complexes to modulate the expression of glucose transporter genes, thereby regulating glucose sensing and insulin secretion. Our findings shed light on insulin secretion control, providing potential avenues for therapeutics against diabetes.

Optimal surgical management of unifocal vs. multifocal NF-PNETs: a respective cohort study

BACKGROUND

Pancreatic neuroendocrine tumors (PNETs) represent 1-2% of pancreatic tumors, with recent guidelines recommending active surveillance for non-functioning PNETs (NF-PNETs) smaller than 2 cm. However, the management of multiple NF-PNETs, as well as the influence of tumor number on prognosis, remains under-researched.

METHODS

This retrospective study analyzed NF-PNET patients who underwent pancreatic resection at Severance Hospital between February 1993 and August 2023, comparing the characteristics of patients diagnosed with multifocal tumors and those with unifocal tumors. A subgroup analysis of overall survival (OS) and recurrence-free survival (RFS) was performed based on multifocality employing the Kaplan-Meier method and the log-rank test.

RESULTS

Of 187 patients, 169 (90.4%) had unifocal and 18 (9.6%) had multifocal tumors. Multifocal tumors were more likely to be diffusely spread, necessitating more total pancreatectomies (diffuse tumor location: 4.7% in unifocal vs. 38.9% in multifocal cases, p < 0.001; total pancreatectomy: 4.1% in unifocal vs. 33.3% in multifocal cases, p < 0.001). In patients with NF-PNET who underwent the same extent of pancreatic resection, no significant difference in the incidence of complication was observed regardless of multifocality. Moreover, no significant difference in OS was seen between the unifocal and multifocal groups (log-rank test: p = 0.93). However, the multifocal group exhibited a poorer prognosis in terms of RFS compared to the unifocal group (log-rank test: p = 0.004) Hereditary syndrome, tumor grade, size, lymphovascular invasion, and lymph node metastasis were key factors in the recurrence.

CONCLUSION

This study's findings suggest that the presence of multiple tumors was associated with poorer recurrence-free survival but did not affect long-term survival following surgery. Given the long-term oncologic outcome and quality of life following surgery, resection of tumors over 2 cm is advisable in patients with multifocal PNETs, while a cautious "wait-and-see" approach for smaller tumors (under 2 cm) can minimize the extent of resection and improve the quality of life. In cases with only small multifocal NF-PNETs (< 2 cm), immediate resection may not be crucial, but the higher recurrence rate than that in solitary NF-PNET necessitates intensified surveillance.

The Use of Glucagon-like Peptide-1 Receptor Agonists in Patients with Type 2 Diabetes Mellitus Does Not Increase the Risk of Pancreatic Cancer: A U.S.-Based Cohort Study

BACKGROUND

GLP-1 RAs are widely used for T2DM treatment due to their cardiorenal and metabolic benefits. This study examines the risk of pancreatic cancer with GLP-1 RA use in patients with T2DM.

METHODS

We analyzed TriNetX's deidentified research database using the U.S. Collaborative Network comprising 62 healthcare organizations across the U.S.A. Patients with T2DM were split into two cohorts: one receiving GLP-1 RAs, and one not receiving GLP-1 RAs. We excluded patients with known risk factors for pancreatic cancer, including pancreatic cysts, a personal or family history of BRCA1, BRCA2, CDKN2A, KRAS, MEN1, MLH1, MSH2, NOTCH1, PALB2, PMS2, and PRSS1S genes, family history of pancreatic cancer, and VHL syndrome. Using a 1:1 propensity score-matching model based on baseline characteristics and comorbidities, we created comparable cohorts. We then compared the rate of pancreatic cancer between the two cohorts at a 7-year interval.

RESULTS

Out of 7,146,015 identified patients with T2DM, 10.3% were on a GLP-1 RA and 89.7% were not. Post-PSM, 721,110 patients were in each group. Patients on GLP-1 RAs had a 0.1% risk compared to a 0.2% risk of pancreatic cancer in the 7-year timeframe.

CONCLUSION

The use of GLP-1 RAs in patients with type 2 diabetes mellitus (T2DM) does not appear to substantially elevate the risk of pancreatic cancer; in fact, it may potentially exert a protective effect.

A Japanese Family Meeting the Clinical Diagnostic Criteria for MEN1 with a MEN1 Variant of Uncertain Significance

Multiple gastroenteric, pancreatic, and pituitary neuroendocrine neoplasms (NENs) were diagnosed in a 74-year-old man with a history of primary hyperparathyroidism (PHPT). Germline testing demonstrated a variant of MEN1 (c.1694T>A, p.L565Q), whose pathogenicity was classified as a variant of uncertain significance (VUS) according to the ACMG/AMP guidelines. The same germline variant was detected in the patient's son and daughter, who also showed PHPT or hypercalcemia and met the clinical diagnostic criteria for multiple endocrine neoplasia type 1 (MEN1). During surveillance of the son, multiple pancreatic tumors suggestive of NENs were detected. The pathogenicity of the current MEN1 variant was re-evaluated as likely pathogenic, based on additional family data.

Gastric neuroendocrine neoplasms

Gastric neuroendocrine neoplasms (gNENs) display peculiar site-specific features among all NENs. Their incidence and prevalence have been rising in the past few decades. gNENs comprise gastric neuroendocrine carcinomas (gNECs) and gastric neuroendocrine tumours (gNETs), the latter further classified into three types. Type I anatype II gNETs are gastrin-dependent and develop in chronic atrophic gastritis and as part of Zollinger-Ellison syndrome within a multiple endocrine neoplasia type 1 syndrome (MEN1), respectively. Type III or sporadic gNETs develop in the absence of hypergastrinaemia and in the context of a near-normal or inflamed gastric mucosa. gNECs can also develop in the context of variable atrophic, relatively normal or inflamed gastric mucosa. Each gNEN type has different clinical characteristics and requires a different multidisciplinary approach in expert dedicated centres. Type I gNETs are managed mainly by endoscopy or surgery, whereas the treatment of type II gNETs largely depends on the management of the concomitant MEN1. Type III gNETs may require both locoregional approaches and systemic treatments; NECs are often metastatic and therefore require systemic treatment. Specific data regarding the systemic treatment of gNENs are lacking and are derived from the treatment of intestinal NETs and NECs. An enhanced understanding of molecular and clinical pathophysiology is needed to improve the management and outcomes of patients' gNETs.

The lesion detection rate of Ga-68 DOTATATE PET/MR in multiple endocrine neoplasia type 1

INTRODUCTION

The purpose of the study was to determine the usefulness of Ga-68 DOTATATE PET/MR in the identification of tumours in individuals with multiple endocrine neoplasia type 1 (MEN1).

METHODS

In this retrospective investigation, five individuals who had tested positive for a hereditary MEN1 variant underwent Ga-68 DOTATATE PET/MR between May 2020 and January 2023. Several types of tumours associated with MEN1 were studied. MEN1-related tumours included pituitary, parathyroid, gastroenteropancreatic, and adrenal. The rates of lesion identification between MRI, Ga-68 DOTATATE PET, and Ga-68 DOTATATE PET/MRI were examined. The maximum and mean standard uptake values (SUVmax and SUVmean) were evaluated in carefully delineated volumes of interest (VOI) for the relevant tumours.

RESULTS

Of the 24 primary lesions, 14 were identified by Ga-68 DOTATATE PET, 18 by MRI, and 20 by Ga-68 DOTATATE PET/MRI. Two pituitary tumours were detected by all three techniques. All parathyroid tumours that were not detected by Ga-68 DOTATATE PET and MRI were found by Tc-99m MIBI SPECT/CT or/and EUS. Ga-68 DOTATATE PET/MR detected more gastroenteropancreatic lesions. All adrenal tumours not identified by Ga-68 DOTATATE PET were found by MRI or CT. The median SUVmax for lesions identified on Ga-68 DOTATATE PET/MRI was 18.4 (range, 3.8-85.2), and the median SUVmean was 12.0 (range, 2.3-49.8).

CONCLUSION

The combination of Ga-68 DOTATATE PET and MRI demonstrated a higher detection rate and may be more useful in the work-up of MEN1 providing a panoramic view of MEN1-related lesions. To increase the identification of MEN1-associated neuroendocrine lesions in the parathyroid gland, approaches other than Ga-68 DOTATATE PET/MRI should be used.

Updates on the genetics of multiple endocrine neoplasia

Multiple endocrine neoplasia (MEN) is a group of syndromes with a genetic predisposition to the appearance of endocrine tumors, and shows autosomal dominant transmission. The advent of molecular genetics has led to improvements in the management of MEN in terms of diagnosis, prognosis and therapy. The genetics of MEN is the subject of regular updates, which will be presented throughout this paper. MEN1, the first to be described, is associated with the MEN1 gene. MEN1 is well known in terms of the observed phenotype, with genetic analysis being conclusive in 90% of patients with a typical phenotype, but is negative in around 10% of families with MEN1. Improvement in analysis techniques and the identification of other genes responsable for phenocopies allows the resolution of some, but not all, cases, notably non-familial forms suspected to be fortuitous assocations with tumors. MEN4 is a rare phenocopy of MEN1 linked to constitutional mutations in the CDKN1B gene. Though it closely resembles the phenotype of MEN1, published data suggests the appearance of tumors is later and less frequent in MEN4. MEN2, which results from mutations in the RET oncogene, shows a strong genotype-phenotype correlation. This correlation is particularly evident in the major manifestation of MEN2, medullary thyroid carcinoma (MTC), in which disease aggressiveness is dependent on the pathogenic variant of RET. However, recent studies cast doubt on this correlation between MTC and pathogenic variant. Lastly, the recent description of families carrying a mutation in MAX, which is known to predispose to the development of pheochromocytoma and paraganglioma, and presents a phenotypic spectrum that evokes MEN, suggests the existence of another syndrome, MEN5.

Tall stature and gigantism in transition age: clinical and genetic aspects-a literature review and recommendations

PURPOSE

Tall stature is defined as height greater than the threshold of more than 2 standard deviations above the average population height for age, sex, and ethnicity. Many studies have described the main aspects of this condition during puberty, but an analysis of the characteristics that the physician should consider in the differential diagnosis of gigantism-tall stature secondary to a pituitary tumour-during the transition age (15-25 years) is still lacking.

METHODS

A comprehensive search of English-language original articles was conducted in the MEDLINE database (December 2021-March 2022). We selected all studies regarding epidemiology, genetic aspects, and the diagnosis of tall stature and gigantism during the transition age.

RESULTS

Generally, referrals for tall stature are not as frequent as expected because most cases are familial and are usually unreported by parents and patients to endocrinologists. For this reason, lacking such experience of tall stature, familiarity with many rarer overgrowth syndromes is essential. In the transition age, it is important but challenging to distinguish adolescents with high constitutional stature from those with gigantism. Pituitary gigantism is a rare disease in the transition age, but its systemic complications are very relevant for future health. Endocrine evaluation is crucial for identifying conditions that require hormonal treatment so that they can be treated early to improve the quality of life and prevent comorbidities of individual patient in this age range.

CONCLUSION

The aim of our review is to provide a practical clinical approach to recognise adolescents, potentially affected by gigantism, as early as possible.

Performance of [18F]fluorocholine PET/CT in MEN1-related primary hyperparathyroidism before initial surgery or for persistent/recurrent disease

PURPOSE

The aims of the study were to evaluate the performance and robustness of [18F]fluorocholine PET/CT in detecting hyperfunctioning parathyroid glands in MEN1-related primary hyperparathyroidism (pHPT) at different stages of their disease.

METHODS

Retrospective French multicenter study including patients with MEN1 pHPT who underwent [18F]fluorocholine PET/CT at initial diagnosis or for evaluation of persistent/recurrent disease. PET/CT were independently reviewed by two readers in a blinded manner. The assessment of PET/CT on a per-patient basis was assessed using a comprehensive set of criteria that considered pathological findings or agreement with alternative diagnostic methods in non-operated patients. The secondary objectives included the analysis of the performance of PET/CT at a per-lesion level, with reference to a pathological Gold Standard, and examining its interobserver reproducibility.

RESULTS

A total of 71 MEN1 patients were included (73 PET/CT) in the study. At the per-patient level (entire cohort), [18F]fluorocholine PET/CT sensitivity ranged from 98.5 to 100% among the different readers. An average of 1.77 glands per PET was described, with 2.35 glands at the initial diagnosis (n = 23) and 1.5 in previously operated cases (n = 50). PET/CT detected more lesions than conventional imaging work-up (neck ultrasound and/or scintigraphy). At the per-lesion level (41 operated patients), sensitivity ranged across different readers from 84.4 to 87%, and specificity ranged from 94.7 to 98.8%. At initial diagnosis, all patients that exhibited 3 or more abnormal glands on PET underwent subtotal parathyroidectomy while 7 out of 13 patients with 1 or 2 gland abnormalities on PET underwent less than subtotal parathyroidectomy. Finally, the degree of inter-observer agreement was high.

CONCLUSION

[18F]fluorocholine PET/CT is a reliable and robust imaging modality for the evaluation of MEN1-related pHPT and could guide surgeons in achieving the optimal benefit-risk ratio. This study gives a great impetus for its adoption as a primary diagnostic tool in this context.

PDP type brain tumor in association with multiple endocrine neoplasia type 1

Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant syndrome caused by inactivating pathogenic variants in the tumor suppressor gene menin 1 on chromosome 11q13 (Falchetti et al., 2009). The syndrome is characterized by neoplasia in two or more endocrine glands and has a high degree of penetrance. Pathogenic germline multiple neoplasia type 1 variants primarily result in neoplasia affecting the parathyroid glands, the pancreatic islet cells, and the anterior pituitary in combination. Primary hyperparathyroidism is the most common pathological manifestation of the syndrome, followed by pancreatic neuroendocrine tumors. Important genetic confirmation has been provided showing that ependymoma should be considered as a neoplasm that can occur in patients with MEN1 (Kato et al., 1996; Cuevas-Ocampo et al., 2017). The biphasic histopathological tumor entity shown in the present case we name Pleomorphic Xanthoastocytoma grade 3 differential pathology (PDP) in association with Multiple Endocrine Neoplasia type 1. This MEN1 associated tumor subtype is an extension of the findings on MEN1 associated ependymoma, where we show that the clinical phenotype itself may potentially be triggered by a frameshift germline pathogenic variant for the MEN1 gene, in combination with cyclin-dependent kinase inhibitor 1B gene germline variant and cyclin dependent kinase inhibitor 2A somatic deletion downstream of menin.

Approach to the Patient: Insulinoma

Insulinomas are hormone-producing pancreatic neuroendocrine neoplasms with an estimated incidence of 1 to 4 cases per million per year. Extrapancreatic insulinomas are extremely rare. Most insulinomas present with the Whipple triad: (1) symptoms, signs, or both consistent with hypoglycemia; (2) a low plasma glucose measured at the time of the symptoms and signs; and (3) relief of symptoms and signs when the glucose is raised to normal. Nonmetastatic insulinomas are nowadays referred to as "indolent" and metastatic insulinomas as "aggressive." The 5-year survival of patients with an indolent insulinoma has been reported to be 94% to 100%; for patients with an aggressive insulinoma, this amounts to 24% to 67%. Five percent to 10% of insulinomas are associated with the multiple endocrine neoplasia type 1 syndrome. Localization of the insulinoma and exclusion or confirmation of metastatic disease by computed tomography is followed by endoscopic ultrasound or magnetic resonance imaging for indolent, localized insulinomas. Glucagon-like peptide 1 receptor positron emission tomography/computed tomography or positron emission tomography/magnetic resonance imaging is a highly sensitive localization technique for seemingly occult, indolent, localized insulinomas. Supportive measures and somatostatin receptor ligands can be used for to control hypoglycemia. For single solitary insulinomas, curative surgical excision remains the treatment of choice. In aggressive malignant cases, debulking procedures, somatostatin receptor ligands, peptide receptor radionuclide therapy, everolimus, sunitinib, and cytotoxic chemotherapy can be valuable options.

Heterogeneity of Multiple Pancreatic Neuroendocrine Tumors Identified by 68Ga-DOTANOC and 68Ga-Exendin-4 PET/CT in a Patient with Endogenous Hyperinsulinemic Hypoglycemia and Multiple Endocrine Neoplasia 1

INTRODUCTION

Insulinomas are the most frequent functional pancreatic neuroendocrine tumors. In about 10% of cases, insulinomas are associated with hereditary syndromes, including multiple endocrine neoplasia 1 (MEN1).

CASE PRESENTATION

Herein, we present a 44-year-old female with recurrent hypoglycemia. In December 1998, this patient underwent resection of two pancreatic lesions due to hypoglycemia and was diagnosed with insulinoma. After the operation, the symptoms of hypoglycemia disappeared. However, from 2021, hypoglycemic symptoms reappeared frequently, as did coma. In June 2023, enhanced CT showed multiple pancreatic lesions abundant with blood supply. Fasting serum blood glucose and insulin were 1.73 mmol/L and 15.2 U/L (2.6-11.8 U/L). Germline genes suggested MEN1 pathogenic mutations. 68Ga-DOTANOC PET/CT indicated there were multiple lesions located in the pancreas and duodenum with high expression of the somatostatin receptor (SSTR). 68Ga-exendin-4 PET/CT was added to localize the insulinoma. Most lesions with high expression of SSTR in the body and tail of the pancreas manifested parts of them with high uptake of 68Ga-exendin-4, and an additional lesion with high expression of glucagon-like peptide-1 receptor (GLP-1R) was only detected by 68Ga-exendin-4 PET/CT. It showed inter-tumor heterogeneity in the expression of SSTR and GLP-1R. From the distal pancreatectomy, a total of 5 tumors were found in the body and tail of the pancreas, which were diagnosed as neuroendocrine tumors (NETs). After the operation, all the symptoms related to hypoglycemia disappeared. Immunohistochemical results of SSTR2 and insulin were consistent with the imaging findings of dual-tracer PET/CT.

CONCLUSION

From this case, a combination of 68Ga-DOTANOC and 68Ga-exendin-4 PET/CT was recommended in the patients with MEN1 and insulinoma to estimate the heterogeneity of multiple neuroendocrine tumors that contribute to detect all the NET lesions and locate the tumors with secretion of insulin.

Genetics of hereditary forms of primary hyperparathyroidism

Primary hyperparathyroidism (PHPT), a relatively common disorder characterized by hypercalcemia with raised or inappropriately normal serum parathyroid hormone (PTH) concentrations, may occur as part of a hereditary syndromic disorder or as a non-syndromic disease. The associated syndromic disorders include multiple endocrine neoplasia types 1-5 (MEN1-5) and hyperparathyroidism with jaw tumor (HPT-JT) syndromes, and the non-syndromic forms include familial hypocalciuric hypercalcemia types 1-3 (FHH1-3), familial isolated hyperparathyroidism (FIHP), and neonatal severe hyperparathyroidism (NS-HPT). Such hereditary forms may occur in > 10% of patients with PHPT, and their recognition is important for implementation of gene-specific screening protocols and investigations for other associated tumors. Syndromic PHPT tends to be multifocal and multiglandular with most patients requiring parathyroidectomy with the aim of limiting end-organ damage associated with hypercalcemia, particularly osteoporosis, nephrolithiasis, and renal failure. Some patients with non-syndromic PHPT may have mutations of the MEN1 gene or the calcium-sensing receptor (CASR), whose loss of function mutations usually cause FHH1, a disorder associated with mild hypercalcemia and may follow a benign clinical course. Measurement of the urinary calcium-to-creatinine ratio clearance (UCCR) may help to distinguish patients with FHH from those with PHPT, as the majority of FHH patients have low urinary calcium excretion (UCCR < 0.01). Once genetic testing confirms a hereditary cause of PHPT, further genetic testing can be offered to the patients' relatives and subsequent screening can be carried out in these affected family members, which prevents inappropriate testing in normal individuals.

Utility of Intraoperative Intrinsic Near-Infrared Imaging for Primary Hyperparathyroidism in Multiple Endocrine Neoplasia Type 1

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder caused by mutations in the tumor suppressor gene MEN1 and is characterized by parathyroid, pancreatic islet, and anterior pituitary tumors. Primary hyperparathyroidism is the most characteristic finding in MEN1, and intraoperative identification and accurate removal of the diseased parathyroid glands are vital since incomplete excision results in recurrence. This case report describes a 59-year-old woman who had pancreatic islet cell tumors and pituitary tumors and underwent selective transsphenoidal adenomectomy. Based on her medical history and examination, the diagnosis of primary hyperparathyroidism in MEN1 was made, and she underwent total parathyroidectomy with autotransplantation with SPY-Elite®️ Fluorescence Imaging (Stryker Corp., Kalamazoo, MI). Intraoperative identification of the parathyroid glands using autofluorescence with real-time intrinsic near-infrared (NIR) imaging made it easier to detect all of the parathyroid hyperplasia. After the surgery, she had hypoparathyroidism and continued with her oral calcium and vitamin D supplementation to maintain normal calcium levels during follow-up. Herein, we would like to advocate that the use of parathyroid gland autofluorescence with real-time intrinsic NIR imaging may be useful for identifying parathyroid tumors in patients with primary hyperparathyroidism in MEN1.