Glucagonoma and the glucagonoma syndrome - cumulative experience with an elusive endocrine tumour

Characteristics, therapy, and outcome of rare functioning pancreatic neuroendocrine neoplasms

Functioning pancreatic neuroendocrine neoplasms other than insulinomas and gastrinomas (rf-pNENs) are exceptionally rare tumours. Thus, their characteristics and long-term prognosis have not been well defined. This article aims to present data and experience from a single institution concerning this topic. Twelve of 216 (5.5%) patients with pNENs operated between 2002 and 2022 in the ENETS Centre of Excellence Marburg had rf-pNENs and their data were retrospectively analysed. We identified three vasoactive intestinal polypeptide producing pNENs, four glucagonomas and five calcitoninomas. The tumour could be visualised by preoperative imaging in all 12 patients, and six patients had distant metastases at the time of diagnosis. The tumour was located in the pancreatic tail in nine patients and the median tumour size was 82 (range 12-220) mm. Eleven patients underwent tumour resections (two robotic, nine conventional), nine of which were R0. After a median follow-up of 75 (range 1-247) months, six patients were alive, five of whom had no evidence of disease. All patients who remained disease-free had an initial R0 resection of the primary tumour and no initial liver involvement. This study sheds light on the distinct characteristics and outcomes of these exceedingly rare tumours, offering insights for improved understanding and management.

Diagnosis and comprehensive treatment of a glucagonoma in a patient with residual intrahepatic metastases postoperatively: A case report and literature review

Glucagonomas are rare neuroendocrine neoplasms of the pancreas with malignant potential. At present, their epidemiology is not entirely clear, so clinicians are not well versed, lacking any consensus on diagnosis or comprehensive treatment. The present study reports the case of a 32-year-old woman hospitalized for recurrent glossitis, perioral dermatitis and necrolytic migratory erythema (NME) of both lower limbs. Imaging studies revealed a low-density nodule (~2 cm) in the tail of the pancreas, as well as multiple space-occupying hepatic lesions. Surgical intervention was then selected, and distal pancreatectomy, splenectomy and palliative metastasectomies were performed. Tissue examination subsequently confirmed a primary pancreatic neuroendocrine tumor (grade 2), metastatic to the liver. The NME resolved postoperatively, aided by intramuscular injections of long-acting release octreotide (30 mg) every 28 days. A series of three percutaneous ablative treatments (microwave ablation) were also undertaken within a 2-year period, targeting the liver metastases. The present condition of the patient is good, with no cutaneous relapse to date. Palliative metastasectomies, in conjunction with ablative treatments and combination somatostatin analog (SSA) use, are unique aspects of this case that, to the best of our knowledge, have yet to be documented in the literature. Surgical palliation may benefit patients with liver involvement and prolong their survival time. Likewise, ablative treatments and SSA injections delivered together not only address hepatic spread, but also control hormone-related symptoms, having a positive impact on prognosis. As glucagonomas are so rare, there is no real agreement on their management. The present study aims to guide clinical practice by adding further to the available data.

Contemporary Approaches to the Surgical Management of Pancreatic Neuroendocrine Tumors

The incidence of pancreatic neuroendocrine tumors (PNETs) is on the rise primarily due to the increasing use of cross-sectional imaging. Most of these incidentally detected lesions are non-functional PNETs with a small proportion of lesions being hormone-secreting, functional neoplasms. With recent advances in surgical approaches and systemic therapies, the management of PNETs have undergone a paradigm shift towards a more individualized approach. In this manuscript, we review the histologic classification and diagnostic approaches to both functional and non-functional PNETs. Additionally, we detail multidisciplinary approaches and surgical considerations tailored to the tumor's biology, location, and functionality based on recent evidence. We also discuss the complexities of metastatic disease, exploring liver-directed therapies and the evolving landscape of minimally invasive surgical techniques.

Established and novel circulating neuroendocrine tumor biomarkers for diagnostic, predictive and prognostic use

The management of neuroendocrine tumors (NETs) represents a clinical challenge due to heterogeneity of their clinical behaviour, molecular biology and response to treatment. Over the years, several circulating biomarkers have been developed for the early diagnosis and follow-up of NETs. The specific secretory products of tumors associated with a secretory syndrome (functioning tumors) may be used as diagnostic and/or prognostic biomarkers while the most common non-specific circulating biomarkers, that may be increased in both functioning and non-functioning tumors, are chromogranin A and the neuron specific enolase. However, the diagnostic accuracy as well as the prognostic and predictive value of these biomarkers are limited and novel techniques of multianalyte analysis of regulators of tumor biology have been developed. The NETest has been most extensively studied and proved to be useful in NET diagnosis, early detection of post-operative recurrence and prediction of response to treatment but further investigation establishing higher level of evidence is required for implementation in clinical practice.

Diabetes Mellitus Secondary to Endocrine Diseases: An Update of Diagnostic and Treatment Particularities

Secondary diabetes mellitus is frequently ignored in specialized literature. In this narrative review, the main endocrinopathies accompanied by increased glycemic values are identified, as well as the mechanisms by which the excess or deficiency of certain hormones impact beta cell function or insulin resistance. The main endocrinopathies (acromegaly, Cushing's syndrome, Basedow-Graves' disease, pheochromocytoma, somatostatinoma and glucagonoma) and their characteristics are described along with the impact of hormone changes on blood sugar, body mass index and other parameters associated with diabetes. The overall information regarding the complex molecular mechanisms that cause the risk of secondary diabetes and metabolic syndrome is of crucial importance in order to prevent the development of the disease and its complications and particularly to reduce the cardiovascular risk of these patients. The purpose of this study is to highlight the particular features of endocrine pathologies accompanied by an increased risk of developing diabetes, in the context of personalized therapeutic decision making. The epidemiological, physiopathological, clinical and therapeutic approaches are presented along with the importance of screening for diabetes in endocrine diseases.

An Insight on Functioning Pancreatic Neuroendocrine Neoplasms

Pancreatic neuroendocrine neoplasms (PanNENs) are rare neoplasms arising from islets of the Langerhans in the pancreas. They can be divided into two groups, based on peptide hormone secretion, functioning and nonfunctioning PanNENs. The first group is characterized by different secreted peptides causing specific syndromes and is further classified into subgroups: insulinoma, gastrinoma, glucagonoma, somatostatinoma, VIPoma and tumors producing serotonin and adrenocorticotrophic hormone. Conversely, the second group does not release peptides and is usually associated with a worse prognosis. Today, although the efforts to improve the therapeutic approaches, surgery remains the only curative treatment for patients with PanNENs. The development of high-throughput techniques has increased the molecular knowledge of PanNENs, thereby allowing us to understand better the molecular biology and potential therapeutic vulnerabilities of PanNENs. Although enormous advancements in therapeutic and molecular aspects of PanNENs have been achieved, there is poor knowledge about each subgroup of functioning PanNENs.Therefore, we believe that combining high-throughput platforms with new diagnostic tools will allow for the efficient characterization of the main differences among the subgroups of functioning PanNENs. In this narrative review, we summarize the current landscape regarding diagnosis, molecular profiling and treatment, and we discuss the future perspectives of functioning PanNENs.

The past, present, and future physiology and pharmacology of glucagon

The evolution of glucagon has seen the transition from an impurity in the preparation of insulin to the development of glucagon receptor agonists for use in type 1 diabetes. In type 2 diabetes, glucagon receptor antagonists have been explored to reduce glycemia thought to be induced by hyperglucagonemia. However, the catabolic actions of glucagon are currently being leveraged to target the rise in obesity that paralleled that of diabetes, bringing the pharmacology of glucagon full circle. During this evolution, the physiological importance of glucagon advanced beyond the control of hepatic glucose production, incorporating critical roles for glucagon to regulate both lipid and amino acid metabolism. Thus, it is unsurprising that the study of glucagon has left several paradoxes that make it difficult to distill this hormone down to a simplified action. Here, we describe the history of glucagon from the past to the present and suggest some direction to the future of this field.

Necrolytic migratory erythema is an important visual cutaneous clue of glucagonoma

Glucagonoma is an extremely rare neuroendocrine tumor that arises from pancreatic islet alpha cells. Although glucagonoma is usually accompanied by a variety of characteristic clinical symptoms, early diagnosis is still difficult due to the scarcity of the disease. In this study, we present the cumulative experiences, clinical characteristics and treatments of seven patients diagnosed with glucagonoma during the past 10 years at the First Affiliated Hospital of Xi'an Jiaotong University. The seven patients in our cohort consisted of six females and one male with an average diagnosis age of 40.1 years (range 23-51). The average time from onset of symptoms to diagnosis of glucagonoma was 14 months (range 2-36 months). All the patients visited dermatology first for necrolytic migratory erythema (NME) 7/7 (100%), and other presenting symptoms included diabetes mellitus (DM) 4/7 (57%), stomatitis 2/7 (28%), weight loss 4/7 (57%), anemia 4/7 (57%), diarrhea 1/7 (14%), and DVT1/7 (14%). Plasma glucagon levels were increased in all patients (range 216.92-3155 pg/mL) and declined after surgery. Imaging studies revealed that four of seven patients had liver metastasis. Six of seven patients received surgical resection, and all of them received somatostatin analog therapy. Symptoms improved significantly in 6 out of 7 patients. Three of seven patients died of this disease by the time of follow-up. Our data suggest that if persistent NME is associated with DM and high glucagon levels, timely abdominal imaging should be performed to confirm glucagonoma. Once diagnosed, surgery and somatostatin analogs are effective for symptom relief and tumor control.

A Glucagonoma Presenting as Cerebral Vein Thrombosis and Diabetes

Glucagonomas are rare pancreatic neuroendocrine tumors (pNETs), malignant in 80% of cases, thus highlighting the importance of early diagnosis and treatment. Primary manifestations are diabetes, dermatosis, depression, weight loss, and deep vein thrombosis. Unlike other pNETs, glucagonomas are associated with a higher incidence of thromboembolic events, often resulting in death. We present the case of a glucagonoma patient whose primary manifestation was cerebral sinus venous thrombosis (CS-VT). Early diagnosis enabled curative resection. The purpose of this paper is to review the underlying mechanisms associated with increased coagulopathy in glucagonomas.

Vasoactive intestinal peptide secreting tumour: An overview

Vasoactive intestinal peptide (VIP) secreting tumour (VIPoma) is a rare functional neuroendocrine tumour that typically arises from pancreatic islet cells. These present as sporadic, solitary pancreatic neoplasias with an estimated incidence of one in ten million individuals per year. Only around 5% of VIPomas are associated with multiple endocrine neoplasia type I syndrome. Excessive VIP secretion produces a clinical syndrome characterized by refractory watery diarrhoea, hypokalemia and metabolic acidosis. These coupled with elevated plasma levels of VIP are diagnostic. The majority of VIPomas are malignant and have already metastasized at the time of diagnosis (60%). Metastases occur most frequently in the liver, or regional lymph nodes, lungs, kidneys and bones. Some reports of skin metastases have been documented. Complete surgical resection continues to be the only potentially curative treatment. However, when the neoplasia cannot be excised completely, surgical debulking may provide palliative benefit. Other palliative options have included recently the peptide receptor radionuclide therapy which has shown to be effective and well-tolerated. This article will review all aspects of pancreatic VIPomas highlighting aspects such as clinical presentation, diagnosis and management.

Thrombotic risk in gastroenteropancreatic neuroendocrine tumor patients: a single-center experience

Background

Only scanty specific studies are available on venous thromboembolism (VTE) in neuroendocrine neoplasms (NEN). We retrospectively assessed the incidence of VTE in gastroenteropancreatic (GEP) NEN patients.

Methods

Between 2000 and 2016, GEP-NEN patients were retrospectively evaluated for VTE. Major thrombotic events included deep venous thrombosis (DVT) and pulmonary embolism (PE). 160 patients were included. The primary tumor site was: the gut in 99, pancreas in 54, and unknown in 7. A total of 93 patients had grade (G) 1 tumor, 36 G2, 4 G3; G was not available in 27 patients. TNM stage was I in 76 patients, II in 17, III in 23, and IV in 44.

Results

Twelve patients developed VTE: 9 had DVT and 3 PE. The primary site of the tumor was located in the pancreas in 9 patients, in the gut in 2, and it was unknown in one patient. Two patients had a functioning tumor. Grading was G1 in 3 patients, G2 in 6, G3 in 2 cases, and not available in one. The TNM stage was IV in 5 patients, III in 2, II in 3, and I in 2. Two patients died during the study period, one of whom died from PE.

Conclusion

GEP-NEN patients harbor a considerable risk of VTE, particularly high for pancreatic NEN patients, for patients with moderate-poorly differentiated neoplasms, and at an advanced tumor stage.

Repositioning the Alpha Cell in Postprandial Metabolism

Glucose homeostasis is maintained in large part due to the actions of the pancreatic islet hormones insulin and glucagon, secreted from β- and α-cells, respectively. The historical narrative positions these hormones in opposition, with insulin primarily responsible for glucose-lowering and glucagon-driving elevations in glucose. Recent progress in this area has revealed a more complex relationship between insulin and glucagon, highlighted by data demonstrating that α-cell input is essential for β-cell function and glucose homeostasis. Moreover, the common perception that glucagon levels decrease following a nutrient challenge is largely shaped by the inhibitory effects of glucose administration alone on the α-cell. Largely overlooked is that a mixed nutrient challenge, which is more representative of typical human feeding, actually stimulates glucagon secretion. Thus, postprandial metabolism is associated with elevations, not decreases, in α-cell activity. This review discusses the recent advances in our understanding of how α-cells regulate metabolism, with a particular focus on the postprandial state. We highlight α- to β-cell communication, a term that describes how α-cell input into β-cells is a critical axis that regulates insulin secretion and glucose homeostasis. Finally, we discuss the open questions that have the potential to advance this field and continue to evolve our understanding of the role that α-cells play in postprandial metabolism.

Understanding the Management and Treatment of Well-Differentiated Pancreatic Neuroendocrine Tumors: A Clinician's Guide to a Complex Illness

Pancreatic neuroendocrine tumors (PanNETs) are rare neoplasms that arise in the neuroendocrine cells of the pancreas. Although their clinical presentations differ depending on cell type, most are indolent, whereas others cause noteworthy hormone-related symptoms. The increasing incidence of PanNETs, attributed to improved diagnostic modalities, demonstrates advances in current standard of care. However, given the heterogeneity of these tumors, treatment decisions can become complex and an individualized approach is often required. Surgical intervention has remained the mainstay for localized tumors, whereas systemic therapies remain viable options for patients with unresectable or metastatic disease. Liver-directed therapies such as radiofrequency ablation and hepatic arterial embolization have also become available adjunct therapies for patients with liver-predominant metastases. Despite the increase in the armamentarium of treatment options for patients with PanNETs, data regarding the ideal sequence of treatment, especially systemic treatments, are currently lacking. Ongoing clinical trials are aimed at addressing this knowledge gap in addition to developing the next generation of novel therapeutics.

Glucagonoma: From skin lesions to the neuroendocrine component (Review)

Glucagonoma is a hormonally active rare pancreatic neuroendocrine tumour causing an excess of glucagon. This is a narrative review based on a multidisciplinary approach of the tumour. Typically associated dermatosis is necrolytic migratory erythema (NME) which is most frequently seen at disease onset. Insulin-dependent diabetes mellitus, depression, diarrhoea, deep vein thrombosis are also identified, as parts of so-called 'D' syndrome. Early diagnosis is life saving due to potential aggressive profile and high risk of liver metastasis. NME as paraneoplastic syndrome may be present for months and even years until adequate recognition and therapy; it is remitted after successful pancreatic surgery. Thus the level of practitioners' awareness is essential. If surgery is not curative, debulking techniques may improve the clinical aspects and even the outcome in association with other procedures such as embolization of hepatic metastasis; ablation of radiofrequency type; medical therapy including chemotherapy, targeted therapy with mTOR inhibitors such as everolimus, PRRT (peptide receptor radiotherapy), and somatostatin analogues (including combinations of medical treatments). Increased awareness of the condition involves multidisciplinary practitioners.

Benign-Appearing Glucagonoma Undergoing Malignant Transformation after a Prolonged Period

Glucagonoma are rare neuroendocrine tumors arising in the Langerhans islets of the pancreas. We report a patient with glucagonoma differentiation into a malignant form after 13 years. A 63-year-old asymptomatic man was evaluated for an enhancing lesion at the distal pancreas. Physical examination was normal. Laboratory values were normal except for an elevated serum glucagon level (206 pg/mL, Ref. 50-150). Somatostatin and other tumor markers were normal. A PET scan confirmed abnormal uptake at the distal pancreas, correlating with a CT scan. The patient underwent laparoscopic distal pancreatectomy with resection of a 2.6-cm mass which predominantly expressed glucagon. Serum glucagon levels normalized immediately postoperatively. He remained asymptomatic for 13 years with normal blood glucose, glucagon, and chromogranin levels and normal surveillance MRI scans. Thirteen years following surgery, an elevated serum glucagon level (230 pg/mL) was observed. At this time he also remained asymptomatic. Abdominal MRI and a PET scan revealed hepatic lesions. Biopsy of the hepatic lesion confirmed metastatic glucagonoma. The patient was treated with lanreotide, which normalized the serum glucagon levels, and the tumor size remained stable for 12 months of follow-up. Complete remission without any treatment for more than 13 years confirmed the benign course of the glucagon-secreting tumor. The precipitating factors are unknown. This case highlights the importance of continuous monitoring of neuroendocrine tumors even beyond 10 years.

Multiple Endocrine Neoplasia: Spectrum of Abdominal Manifestations

OBJECTIVE. Multiple endocrine neoplasia (MEN) syndromes are autosomal-dominant genetic disorders that predispose two or more organs of the endocrine system to tumor development. Although the diagnosis relies on clinical and serologic findings, imaging provides critical information for surgical management with the ultimate goal of complete tumor resection. CONCLUSION. This article reviews abdominal neoplasms associated with the various subtypes of MEN syndromes, with a focus on clinical presentation and characteristic imaging features.

Biomarkers for Pancreatic Neuroendocrine Neoplasms (PanNENs) Management-An Updated Review

Pancreatic neuroendocrine tumors (PanNENs) are rare sporadic cancers or develop as part of hereditary syndromes. PanNENs can be both functioning and non-functioning based on whether they produce bioactive peptides. Some PanNENs are well differentiated while others-poorly. Symptoms, thus, depend on both oncological and hormonal causes. PanNEN diagnosis and treatment benefit from and in some instances are guided by biomarker monitoring. However, plasmatic monoanalytes are only suggestive of PanNEN pathological status and their positivity is typically followed by deepen diagnostic analyses through imaging techniques. There is a strong need for new biomarkers and follow-up modalities aimed to improve the outcome of PanNEN patients. Liquid biopsy follow-up, i.e., sequential analysis on tumor biomarkers in body fluids offers a great potential, that need to be substantiated by additional studies focusing on the specific markers and the timing of the analyses. This review provides the most updated panorama on PanNEN biomarkers.

Cutaneous manifestations of internal malignancy

Skin lesions associated with internal malignancy may present as cutaneous metastases or as typical lesions occurring in the context of certain cancer-associated genetic syndromes. Paraneoplastic syndromes, on the other hand, are only indirectly associated with an underlying malignancy and are not malignant per se. Historically, a distinction has been made between "obligate" and "facultative" paraneoplastic disorders, depending on the likelihood with which they are potentially associated with malignancy. In addition, there are nonspecific cutaneous manifestations that are only rarely associated with an underlying malignancy. Another possible classification is based on the pathophysiological mechanisms underlying the cutaneous lesions. In everyday practice, it is essential that dermatologists recognize potentially cancer-associated dermatoses, as this will frequently contribute to the initial diagnosis of an underlying neoplasm.

Advances in the Diagnosis and Management of Well-Differentiated Neuroendocrine Neoplasms

Neuroendocrine neoplasms constitute a diverse group of tumors that derive from the sensory and secretory neuroendocrine cells and predominantly arise within the pulmonary and gastrointestinal tracts. The majority of these neoplasms have a well-differentiated grade and are termed neuroendocrine tumors (NETs). This subgroup is characterized by limited proliferation and patients affected by these tumors carry a good to moderate prognosis. A substantial subset of patients presenting with a NET suffer from the consequences of endocrine syndromes as a result of the excessive secretion of amines or peptide hormones, which can impair their quality of life and prognosis. Over the past 15 years, critical developments in tumor grading, diagnostic biomarkers, radionuclide imaging, randomized controlled drug trials, evidence-based guidelines, and superior prognostic outcomes have substantially altered the field of NET care. Here, we review the relevant advances to clinical practice that have significantly upgraded our approach to NET patients, both in diagnostic and in therapeutic options.

The Liver-α-Cell Axis and Type 2 Diabetes

Both type 2 diabetes (T2D) and nonalcoholic fatty liver disease (NAFLD) strongly associate with increasing body mass index, and together these metabolic diseases affect millions of individuals. In patients with T2D, increased secretion of glucagon (hyperglucagonemia) contributes to diabetic hyperglycemia as proven by the significant lowering of fasting plasma glucose levels following glucagon receptor antagonist administration. Emerging data now indicate that the elevated plasma concentrations of glucagon may also be associated with hepatic steatosis and not necessarily with the presence or absence of T2D. Thus, fatty liver disease, most often secondary to overeating, may result in impaired amino acid turnover, leading to increased plasma concentrations of certain glucagonotropic amino acids (e.g., alanine). This, in turn, causes increased glucagon secretion that may help to restore amino acid turnover and ureagenesis, but it may eventually also lead to increased hepatic glucose production, a hallmark of T2D. Early experimental findings support the hypothesis that hepatic steatosis impairs glucagon's actions on amino acid turnover and ureagenesis. Hepatic steatosis also impairs hepatic insulin sensitivity and clearance that, together with hyperglycemia and hyperaminoacidemia, lead to peripheral hyperinsulinemia; systemic hyperinsulinemia may itself contribute to worsen peripheral insulin resistance. Additionally, obesity is accompanied by an impaired incretin effect, causing meal-related glucose intolerance. Lipid-induced impairment of hepatic sensitivity, not only to insulin but potentially also to glucagon, resulting in both hyperinsulinemia and hyperglucagonemia, may therefore contribute to the development of T2D at least in a subset of individuals with NAFLD.

Spleen-preserving distal pancreatectomy and lymphadenectomy for glucagonoma syndrome: A case report

RATIONALE

Glucagonoma is a rare type of functional pancreatic neuroendocrine tumor that is characterized by distinctive clinical manifestations; among these, necrolytic migratory erythema represents the hallmark clinical sign of glucagonoma syndrome and is usually presented as the initial complaint of patients.

PATIENT CONCERNS

A 30-year-old male patient was admitted to our hospital with a complaint of diffuse erythematous ulcerating skin rash for more than 10 months. He also complained of hyperglycemia and a weight loss of 15 kg in those months.

DIAGNOSIS

This patient underwent a contrast-enhanced computed tomography scan which showed a pancreatic body mass measuring approximately 6 cm with low density accompanied by partial calcification in plain scanning images and uneven enhancement in strengthening periods. In addition, laboratory tests indicated elevated fasting blood glucagon (1109 pg/mL, normal range: 50-150 pg/mL) levels. Glucagonoma syndrome was ultimately diagnosed in clinical.

INTERVENTION

Spleen-preserving distal pancreatectomy was conducted and postoperative pathology revealed the presence of glucagonoma.

OUTCOMES

The patient recovered uneventfully with the glucagonoma syndrome disappeared soon after surgery, and the postoperative plasma glucagon decreased to a normal level. Follow-up showed no recurrence for 5 years since the surgery.

LESSONS

The treatment of glucagonoma should be directed according to the stage at which the disease is diagnosed. Surgery is currently the only method available to cure the tumor, although medications are given to patients who present with advanced glucagonoma and who are not candidates for operation. Multidisciplinary therapy and multimodality treatment are advised, although these have been systematically evaluated to a lesser degree.

Resolution of necrolytic migratory erythema with somatostatin analogue in a patient diagnosed with pancreatic glucagonoma

A 70-year-old man reported progressive weight loss, fatigue and a generalised rash. The rash was consistent with necrolytic migratory erythema, further investigations were performed and the patient was diagnosed with a mass in the tail of the pancreas, in keeping with a localised glucagonoma. Somatostatin analogue therapy was started for symptom control, leading to complete resolution of the skin rash and an improvement in constitutional symptoms. Subsequently, the pancreatic lesion was excised, and pathology assessment confirmed the diagnosis of well-differentiated neuroendocrine tumour with high expression of glucagon compatible with glucagonoma.

Octreotide Use in a Patient with MEN-1 Syndrome and Multifocal Pancreatic Neuroendocrine Tumors: A Case Report and Review of the Literature

We report a patient with multiple endocrine neoplasia type 1 with pancreatic polypeptide (PP) secreting subcentimeter pancreatic neuroendocrine tumors (pNETs) treated with octreotide and review the current literature that pertains to the management of these patients. Clinical data, laboratory results, and imaging were reviewed. A literature search was performed in PUBMED using combinations of the terms “multiple endocrine neoplasia type 1,” “somatostatin,” octreotide,” “pancreatic polypeptide,” and “pancreatic tumor.” Relevant references were selected and reviewed. A 43-year-old male with a history of MEN1 and multiple subcentimeter neuroendocrine tumors with elevation of PP was treated with octreotide therapy leading to a reduction and normalization of PP levels. The patient tolerated octreotide therapy but self-discontinued octreotide after 24 months with a rise in PP levels off therapy. Tumors remained stable in size through 40 months of imaging follow-up. In patients with MEN1 and subcentimeter pNETs, octreotide therapy is well tolerated and can lead to a significant drop in PP levels with no change in lesion size. There is insufficient data to suggest long-term benefit with octreotide therapy but it may be considered versus standard conservative management.

Paraneoplastic syndromes and other systemic disorders associated with neuroendocrine neoplasms

Neuroendocrine paraneoplastic syndromes (PNS) consist of metabolic disorders that accompany benign and malignant neoplasms but remain unrelated to mass effects or invasion by the primary tumor or its metastases. The underlying pathogenesis responsible for PNS usual clinical presentation relies on aberrant production of protein hormones, proteins and other substances by the tumor. Prompt recognition of characteristic signs and symptoms combined with serological identification of key substances may result in early diagnosis of PNS and its underlying malignancy. For these reasons, healthcare professionals should familiarize themselves with tumor-induced hypercalcemia, syndrome of inappropriate antidiuretic hormone, carcinoid syndrome, virilisation syndrome, gynecomastia, acromegaly, Cushing syndrome, osteogenic osteomalacia, tumor-induced hypoglycemia, necrolytic migratory erythema, and watery diarrhea, hypokalemia and achlorydria syndrome. Medical awareness for PNS can improve patient outcomes through earlier administration of cancer therapy and treatment, better symptomatic relief and prolong overall survival.

Neoplasms of the Neuroendocrine Pancreas: An Update in the Classification, Definition, and Molecular Genetic Advances

This review focuses on discussing the main modifications of the recently published 2017 WHO Classification of Neoplasms of the Neuroendocrine Pancreas (panNEN). Recent updates separate pancreatic neuroendocrine tumors into 2 broad categories: well-differentiated pancreatic neuroendocrine tumors (panNET) and poorly differentiated pancreatic neuroendocrine carcinoma (panNEC), and incorporates a new subcategory of "well-differentiated high-grade NET (G3)" to the well-differentiated NET category. This new classification algorithm aims to improve the prediction of clinical outcomes and survival and help clinicians select better therapeutic strategies for patient care and management. In addition, these neuroendocrine neoplasms are capable of producing large quantity of hormones leading to clinical hormone hypersecretion syndromes. These functioning tumors include, insulinomas, glucagonomas, somatostatinomas, gastrinomas, VIPomas, serotonin-producing tumors, and ACTH-producing tumors. Although most panNENs arise as sporadic diseases, a subset of these heterogeneous tumors present as parts on inherited genetic syndromes, such as multiple endocrine neoplasia type 1, von Hippel-Lindau, neurofibromatosis type 1, tuberous sclerosis, and glucagon cell hyperplasia and neoplasia syndromes. Characteristic clinical and morphologic findings for certain functioning and syndromic panNENs should alert both pathologists and clinicians as appropriate patient management and possible genetic counseling may be necessary.

Role of biomarker tests for diagnosis of neuroendocrine tumours

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

Diabetes and pancreatic neuroendocrine tumours: Which interplays, if any?

Pancreatic neuroendocrine tumours (PanNETs) represent an uncommon type of pancreatic neoplasm, whose incidence is increasing worldwide. As per exocrine pancreatic cancer, a relationship seems to exist between PanNETs and glycaemic alterations. Diabetes mellitus (DM) or impaired glucose tolerance often occurs in PanNET patients as a consequence of hormonal hypersecretion by the tumour, specifically affecting glucose metabolism, or due to tumour mass effects. On the other hand, pre-existing DM may represent a risk factor for developing PanNETs and is likely to worsen the prognosis of such patients. Moreover, the surgical and/or pharmacological treatment of the tumour itself may impair glucose tolerance, as well as antidiabetic therapies may impact tumour behaviour and patients outcome. Differently from exocrine pancreatic tumours, few data are available for PanNETs as yet on this issue. In the present review, the bidirectional association between glycaemic disorders and PanNETs has been extensively examined, since the co-existence of both diseases in the same individual represents a further challenge for the clinical management of PanNETs.

Glucagonoma and Glucagonoma Syndrome: One Center's Experience of Six Cases

Purpose: Glucagonoma is an extremely rare neuroendocrine tumor arising from pancreatic islet cells. Although patients with glucagonoma manifest multiple typical symptoms, early diagnosis remains difficult due to the scarcity of this disease. Methods: In this study, we retrospectively screened the database of the pancreas center of Nanjing Medical University. A total of six cases diagnosed as glucagonoma during the past 17 years were included. Their clinical characteristics and treatments were reviewed. Results: The six patients consisted of four females and two males. Their median age at diagnosis was 48.7 years (range 35-77). The time from onset of symptoms to diagnosis of glucagonoma ranged from 1.3 months to >10 years. Common symptoms included necrotizing migratory erythema shown in six of six patients (100%), diabetes mellitus in five of six patients (83%), stomatitis in four of six patients (67%), and weight loss in four of six patients (67%). Plasma glucagon levels were elevated in all patients (range 245.6-1132.2 pg/mL; n < 200), and significantly declined after surgery (range 29-225.1 pg/mL; n < 200). Imaging studies revealed that three of six patients had metastasis at the time of diagnosis. All patients received surgical resection. The primary lesion, liver metastases, and involved organs were resected in all patients if present. The mean survival time was 5.7 years (range 3-10.4) from diagnosis and four of six patients died of this disease by the time of follow-up. Conclusion: Our data suggest surgery is effective for symptom relief and can control the progress of glucagonoma. Early diagnosis and surgery are crucial for glucagonoma.

Glucagonoma and the glucagonoma syndrome

Glucagonoma is an extremely rare pancreatic α-islet cell tumor and is often accompanied by certain clinical symptoms including necrotizing migratory erythema (NME), diabetes, weight loss and anemia. The objectives of the current review were to discern the clinical features, diagnosis, treatment and prognosis of glucagonoma by evaluating 623 reported cases. A 1998 study reviewed 407 cases and 216 cases were reported in studies published after 1998. The current review consisted of 268 males and 339 females, with an average age of 52.4 years. The male-to-female ratio was 0.79. The incidence of typical clinical findings were as follows: NME, 82.4% (350/425); diabetes, 68.5% (291/425); weight loss, 60.2% (256/425); anemia, 49.6% (211/425); and glossitis or stomatitis or cheilitis, 41.2% (175/425). A total of 499 cases reported the location of the tumor as the pancreas and 64.1% (320/499) involved the pancreatic tail. Tumor size was recorded in 58.3% (126/216) cases reported after 1998 and average tumor size was 5.0 cm. Metastasis was detected in 49.2% of patients (293/595 for whom metastasis or no metastasis were recorded) upon diagnosis. These patients were older than those without metastasis (average age, 54.0 years old vs. 50.8 years old). The average time between symptoms and diagnosis of glucagonoma was 31.4 months. Glucagonoma is a very rare disease. It is important for clinicians to learn more about this disease to be able to diagnose and treat it as early as possible, thus improving patient prognosis.

Malignant transformation of glucagonoma with SPECT/CT In-111 OctreoScan features: A case report

RATIONALE

Glucagonoma is an uncommon disease but it has been associated with a pattern of symptoms defined as glucagonoma syndrome. These symptoms, if promptly recognized, could help to speed up the diagnosing process.

PATIENT CONCERNS

We report a case of a 68-year-old woman with a pancreatic glucagonoma. Her symptoms at the onset were typical of the glucagonoma syndrome.

DIAGNOSES

After a significant weight loss, she underwent a computer tomography scan of the abdomen, which showed a hypervascular lesion of the tail of the pancreas and hypervascular lesions of the liver. An ultrasound guided biopsy was performed and pathology was consistent with glucagonoma. Her blood glucagon levels were elevated.

OUTCOMES

She was treated with chemotherapy and somatostatin analogs. After 4 years, the disease had a malignant transformation, and metastases suddenly started to grow up. She stopped being responsive to treatment and eventually passed away.

LESSONS

Due to its rarity, clinical diagnosis is challenging and generally it comes after a long interval since the onset of symptoms. Awareness of physicians and dermatologists of the characteristic necrolytic migratory erythema, and of the other symptoms, often leads to early diagnosis.

Glucagonoma syndrome with serous oligocystic adenoma: A rare case report

RATIONALE

Glucagonoma and pancreatic serous oligocystic adenoma (SOA) are rare neuroendocrine and exocrine tumors of the pancreas, respectively. The coexistence of glucagonoma syndrome (GS) and SOA is a rare clinical condition and has not yet been reported. Additionally, necrolytic migratory erythema (NME), a hallmark clinical sign of GS, is often misdiagnosed as other skin lesions by clinicians due to their lack of related knowledge, which delays diagnosis of GS and thus exacerbates the prognosis.

PATIENT CONCERNS

A 50-year-old male patient was admitted to our department because he presented with diabetes mellitus and a recurrent ulcerated skin rash. Prior to the accurate diagnosis, the skin manifestation was considered to be diabetic dermopathy.

DIAGNOSES

The patient's fasting serum glucagon level was up to 871.5 pg/mL. A biopsy of the pancreatic tumor revealed a pancreatic neuroendocrine tumor, and immunoperoxidase staining revealed glucagon-positive cells. In addition, the histological examination of the pancreatic cystic lesions showed typical features of SOA.

INTERVENTIONS

The patient received a pancreaticoduodenal resection and radiofrequency ablation for the hepatic nodular lesion.

OUTCOMES

One week after surgery, the glucagon concentration decreased to near normal levels. The cutaneous lesions spontaneously resolved within 4 weeks after surgery.

LESSONS

Because almost all glucagonomas are malignant or have malignant potential, their early recognition and correct diagnosis are very important for a better prognosis, especially in cases with NME as the only manifestation during the development of glucagonomas. It is therefore imperative that clinicians recognize NME early to make an accurate diagnosis.

Effect of hormone secretory syndromes on neuroendocrine tumor prognosis

The treatment of hormone hypersecretory syndromes caused by neuroendocrine tumors (NETs) can be a major challenge. NETs originating from the small intestine often secrete serotonin causing flushing, diarrhea and valve fibrosis, leading to dehydration or heart failure in severe cases. NETs from the pancreas can secrete a wider variety of hormones, like insulin, glucagon and gastrin leading to distinct clinical syndromes. Historically mortality in patients with functioning NETs was high due to the complications caused by the hypersecretion of hormones. This has been reduced with several drugs: proton-pump inhibitors decrease acid secretion caused by gastrinomas. Somatostatin analogs can inhibit the secretion of multiple hormones and these are now the cornerstone for treating patients with a gastroenteropancreatic NET. However, peptide receptor radionuclide therapy (PRRT) with radiolabeled somatostatin analogs and everolimus can also decrease symptoms of hypersecretion and increase progression-free survival. Several factors affect the survival in patients with a functioning NET. Complications of hypersecretion negatively impact survival; however, secretion of hormones is also often a sign of a well-differentiated NET and due to the symptoms, functioning NETs can be detected in an earlier stage suggesting a positive effect on prognosis. The effect on survival is also dependent on the type of hormone being secreted. This review aims to study the effect of hormone secretion on the prognosis of NETs with the contemporary treatments options available today.

Necrolytic Migratory Erythema: A Forgotten Paraneoplastic Condition

Background:

Necrolytic migratory erythema (NME) is most commonly a paraneoplastic condition. It is the dermatologic manifestation classically associated with glucagonoma pancreatic neuroendocrine tumour. Glucagonoma syndrome has been defined by the constellation of secreting tumour associated with overproduction by the α-cells in the pancreatic islets of Langerhans, abnormally elevated blood level of glucagon, and skin findings of NME.

Objective:

Although rare, all dermatologists must know and recognise NME promptly to request useful investigations for the diagnosis of this characteristic neuroendocrine tumour.

Methods and Results:

We report a case of a middle-aged woman seen in our dermatology clinic with longstanding skin findings suggestive of NME revealing a glucagonoma. Surgical removal was associated with complete resolution of the cutaneous and systemic features.

Conclusion:

NME is often the first clinical finding of an occult neuroendocrine pancreatic neoplasia. Dermatologists must be aware of this condition since they can be the first physician to suspect it and allow multidisciplinary management, which influences the prognostic value. Surgical removal is the first-line therapy if early diagnosis is done before liver metastases occur.

Management of the hormonal syndrome of neuroendocrine tumors

Gastroenteropancreatic neuroendocrine tumors (GEP/NET) are unusual and rare neoplasms that present many clinical challenges. They characteristically synthesize store and secrete a variety of peptides and neuroamines which can lead to the development of distinct clinical syndrome, however many are clinically silent until late presentation with mass effects. Management strategies include surgery cure and cytoreduction with the use of somatostatin analogues. Somatostatin have a broad range of biological actions that include inhibition of exocrine and endocrine secretions, gut motility, cell proliferation, cell survival and angiogenesis. Five somatostatin receptors (SSTR1-SSTR5) have been cloned and characterized. Somatostatin analogues include octreotide and lanreotide are effective medical tools in the treatment and present selectivity for SSTR2 and SSTR5. During treatment is seen disapperance of flushing, normalization of bowel movements and reduction of serotonin and 5-hydroxyindole acetic acid (5-HIAA) secretion. Telotristat represents a novel approach by specifically inhibiting serotonin synthesis and as such, is a promising potential new treatment for patients with carcinoid syndrome. To pancreatic functionig neuroendocrine tumors belongs insulinoma, gastrinoma, glucagonoma and VIP-oma. Medical management in patients with insulinoma include diazoxide which suppresses insulin release. Also mTOR inhibitors may inhibit insulin secretion. Treatment of gastrinoma include both proton pump inhibitors (PPIs) and histamine H2 - receptor antagonists. In patients with glucagonomas hyperglycaemia can be controlled using insulin and oral blood glucose lowering drugs. In malignant glucagonomas smatostatin analogues are effective in controlling necrolytic migratory erythemia. Severe cases of the VIP-oma syndrome require supplementation of fluid losses. Octreotide reduce tumoral VIP secretion and control secretory diarrhoea.

Glucagon: acute actions on hepatic metabolism

Type 2 diabetes mellitus is the result of impaired systemic control of glucose homeostasis, in part through the dysregulation of the hormone glucagon. Glucagon acts on the liver to increase glucose production through alterations in hepatic metabolism, and reducing the elevated glucagon signalling in diabetic patients is an attractive strategy for the treatment of hyperglycaemia. Here we review the actions of the hormone in the liver, focusing on the acute alterations of metabolic pathways. This review summarises a presentation given at the 'Novel data on glucagon' symposium at the 2015 annual meeting of the EASD. It is accompanied by two other reviews on topics from this symposium (by Mona Abraham and Tony Lam, DOI: 10.1007/s00125-016-3950-3 , and by Young Lee and colleagues, DOI: 10.1007/s00125-016-3965-9 ) and an overview by the Session Chair, Isabel Valverde (DOI: 10.1007/s00125-016-3946-z ).

Glucagonoma Pancreatic Neuroendocrine Tumor Treated With 177Lu DOTATATE Induction and Maintenance Peptide Receptor Radionuclide Therapy

A 56-year-old man presented with a history of 2 prior resections of a recurrent pancreatic glucagonoma in the past 4 years. Workup revealed new liver and abdominal nodal metastases with a rising serum glucagon level. He was started on peptide receptor radionuclide therapy with Lu DOTATATE, and his disease stabilized, while his glucagon levels decreased and also stabilized. After 4 induction and 2 maintenance cycles, he remains progression free for 23 months.

An optical method to evaluate both mass and functional competence of pancreatic α- and β-cells

Imbalanced glucagon and insulin release leads to the onset of type 2 diabetes. To pinpoint the underlying primary driving force, here we have developed a fast, non-biased optical method to measure ratios of pancreatic α- and β-cell mass and function simultaneously. We firstly label both primary α- and β-cells with the red fluorescent probe ZinRhodaLactam-1 (ZRL1), and then highlight α-cells by selectively quenching the ZRL1 signal from β-cells. Based on the signals before and after quenching, we calculate the ratio of the α-cell to β-cell mass within live islets, which we found matched the results from immunohistochemistry. From the same islets, glucagon and insulin release capability can be concomitantly measured. Thus, we were able to measure the ratio of α-cell to β-cell mass and their function in wild-type and diabetic Lepr(db)/Lepr(db) (denoted db/db) mice at different ages. We find that the initial glucose intolerance that appears in 10-week-old db/db mice is associated with further expansion of α-cell mass prior to deterioration in functional β-cell mass. Our method is extendable to studies of islet mass and function in other type 2 diabetes animal models, which shall benefit mechanistic studies of imbalanced hormone secretion during type 2 diabetes progression.