Improved contemporary surgical management of insulinomas: a 25-year experience at the Massachusetts General Hospital

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.

Diagnostic Modalities, Management Considerations, and Outcomes of Insulinoma: A Case Series from a Tertiary Care Centre

Introduction

Insulinomas are rare, usually sporadic, and typically benign pancreatic neuroendocrine tumours. Pre-operative localization is challenging and evidence on comparative analysis of anatomic and scintigraphic modalities for pre-operative tumour localization is limited, even in contemporary series.

Methods

The current study was designed to study the clinical features and management challenges of insulinomas managed at a tertiary care centre. Clinical features, diagnosis, imaging techniques, surgical procedures, and outcomes details were collated. Pre-operative imaging techniques (CT/MRI, nuclear scintigraphy) were compared with intraoperative and histopathological findings to assess their accuracy of localization.

Results

Thirty-seven patients (15 females [42%]; median age 36 years [IQR 28-49]) were included in the study. In four patients (10.8%), the tumour occurred in the setting of multiple endocrine neoplasia type 1 (MEN 1) while the remaining were sporadic. The sensitivity of pre-operative localization was 61.5% (multiphasic CT), 66.6% (multiphasic MRI), 100% (68Ga Exendin-4 PET-CT), and 91.6% (EUS). Three patients with normal multiphasic CT had localization on 68Ga Exendin-4 PET-CT. The positive predictive value (PPV) of both Exendin-PET-CT and EUS was similar at 91.6% and 91.6%, respectively. All patients (except one with nesidioblastosis), who underwent enucleation or partial pancreatic resection, were cured.

Conclusion

68Ga Exendin-4 PET-CT based is a non-invasive imaging modality that has high sensitivity and PPV and can be used as a first-line imaging modality. The overall prognosis of these tumours is good with high cure rates attained following surgical resection.

Ectopic insulinoma: a systematic review

Knowledge of ectopic insulinomas comes from single cases. We performed a systematic review through PubMed, Web of Science, Embase, eLibrary and ScienceDirect of all cases reported in the last four decades. We also describe one unreported patient. From 28 patients with ectopic insulinoma, 78.6% were female and mean age was 55.7 ± 19.2 years. Hypoglycaemia was the first symptom in 85.7% while 14.3% complained of abdominal pain or genital symptoms. Median tumour diameter was 27.5 [15-52.5] mm and it was localised by CT (73.1%), MRI (88.9%), [68Ga]Ga-DOTA-exedin-4 PET/CT (100%), 68Ga-labelled-DOTA-conjugated somatostatin analogue PET/TC (100%), somatostatin receptor scintigraphy (40%) and endoscopic ultrasound (50%). Ectopic insulinomas were located at duodenum (n = 3), jejunum (n = 2), and one respectively at stomach, liver, appendix, rectum, mesentery, ligament of Treitz, gastrosplenic ligament, hepatoduodenal ligament and splenic hilum. Seven insulinomas were affecting the female reproductive organs: ovary (n = 5), cervix (n = 2) and remaining tumours were at retroperitoneum (n = 3), kidney (n = 2), spleen (n = 1) and pelvis (n = 1). 89.3% underwent surgery (66.7% surgery vs. 33.3% laparoscopy) and 16% underwent an ineffective pancreatectomy. 85.7% had localized disease at diagnosis and 14.3% developed distant metastasis. Median follow-up time was 14.5 [4.5-35.5] months and mortality was reported in 28.6% with median time until death of 60 [5-144] months. In conclusion, ectopic insulinomas are presented as hypoglycaemia with female preponderance. Functional imaging [68Ga]Ga-DOTA-exedin-4 PET/CT and 68Ga-labelled-DOTA-conjugated somatostatin analogue PET/TC have very high sensitivity. Clinicians should be alert to the possibility of extra-pancreatic insulinomas when classic diagnostic tests and intraoperative pancreas exploration failed to locate the tumour.

Predicting recurrence in pancreatic neuroendocrine tumours: role of ARX and alternative lengthening of telomeres (ALT)

BACKGROUND

While many pancreatic neuroendocrine tumours (PanNET) show indolent behaviour, predicting the biological behaviour of small nonfunctional PanNETs remains a challenge. Nonfunctional PanNETs with an epigenome and transcriptome that resemble islet alpha cells (ARX-positive) are more aggressive than neoplasms that resemble islet beta cells (PDX1-positive). In this study, we explore the ability of immunohistochemistry for ARX and PDX1 and telomere-specific fluorescence in situ hybridisation (FISH) for alternative lengthening of telomeres (ALT) to predict recurrence.

METHODS

Two hundred fifty-six patients with PanNETs were identified, and immunohistochemistry for ARX and PDX1 was performed. Positive staining was defined as strong nuclear staining in >5% of tumour cells. FISH for ALT was performed in a subset of cases.

RESULTS

ARX reactivity correlated with worse disease-free survival (DFS) (P = 0.011), while there was no correlation between PDX1 reactivity and DFS (P = 0.52). ALT-positive tumours (n = 63, 31.8%) showed a significantly lower DFS (P < 0.0001) than ALT-negative tumours (n = 135, 68.2%). ARX reactivity correlated with ALT positivity (P < 0.0001). Among nonfunctional tumours, recurrence was noted in 18.5% (30/162) of ARX-positive tumours and 7.5% (5/67) of ARX-negative tumours. Among WHO grade 1 and 2 PanNETs with ≤2 cm tumour size, 14% (6/43) of ARX-positive tumours recurred compared to 0 of 33 ARX-negative tumours and 33.3% (3/9) ALT-positive tumours showed recurrence versus 4.4% (2/45) ALT-negative tumours.

CONCLUSION

Immunohistochemistry for ARX and ALT FISH status may aid in distinguishing biologically indolent cases from aggressive small low-grade PanNETs, and help to identify patients who may preferentially benefit from surgical intervention.

Mechanism and recent updates on insulin-related disorders

Insulin, a small protein with 51 amino acids synthesized by pancreatic β-cells, is crucial to sustain glucose homeostasis at biochemical and molecular levels. Numerous metabolic dysfunctions are related to insulin-mediated altered glucose homeostasis. One of the significant pathophysiological conditions linked to the insulin associated disorder is diabetes mellitus (DM) (type 1, type 2, and gestational). Insulin resistance (IR) is one of the major underlying causes of metabolic disorders despite its association with several physiological conditions. Metabolic syndrome (MS) is another pathophysiological condition that is associated with IR, hypertension, and obesity. Further, several other pathophysiological disorders/diseases are associated with the insulin malfunctioning, which include polycystic ovary syndrome, neuronal disorders, and cancer. Insulinomas are an uncommon type of pancreatic β-cell-derived neuroendocrine tumor that makes up 2% of all pancreatic neoplasms. Literature revealed that different biochemical events, molecular signaling pathways, microRNAs, and microbiota act as connecting links between insulin disorder and associated pathophysiology such as DM, insuloma, neurological disorder, MS, and cancer. In this review, we focus on the insulin-related disorders and the underlying mechanisms associated with the pathophysiology.

Clinicopathological Features of Insulinoma: A Single Tertiary Center Experience

Insulinoma is a rare pancreatic neuroendocrine tumor with an incidence of 1-4 cases per million. Here we present our 10 years of experience in 13 cases of insulinoma. We retrospectively reviewed all insulinoma patients diagnosed and treated between 2012 and 2022. Clinical and pathological features, diagnostic methods, and follow-up results of insulinoma patients were discussed. A total of 13 patients were included in this study (7 men, and 6 women). The mean age at the time of diagnosis was 58 (36.5-70.5) years. There is only one patient diagnosed with MEN-1 syndrome. The mean time from the onset of symptoms to the diagnosis was 15 (7-27.5) months. In the prolonged fasting test, symptomatic hypoglycemia occurred in all patients within 48 h. The median size of lesions was 15 (12-24) mm, and 46.2% of these lesions were isolated in the pancreatic tail. Ga-68 DOTATATE PET/CT detected lesions with 100% accuracy. Three patients met the criteria for malignant insulinoma. Octreotide LAR was given to 1 patient with metastatic disease and 1 patient who did not accept surgery. The metastatic patient received 8 cycles of Lu treatment and died after 51 months of follow-up. The diagnosis of insulinoma can be challenging. The 48-h fasting test period provided sufficient information for the diagnosis of insulinoma. Ga-68 DOTATATE PET/CT may be an alternative in cases where cross-sectional imaging cannot localize the pancreatic lesion.

Surgical Management of Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (PNETs) are relatively uncommon malignancies, characterized as either functional or nonfunctional secondary to their secretion of biologically active hormones. A wide range of clinical behavior can be seen, with the primary prognostic indicator being tumor grade as defined by the Ki67 proliferation index and mitotic index. Surgery is the primary treatment modality for PNETs. While functional PNETs should undergo resection for symptom control as well as potential curative intent, nonfunctional PNETs are increasingly managed nonoperatively. There is increasing data to suggest small, nonfunctional PNETs (less than 2 cm) are appropriate follow with nonoperative active surveillance. Evidence supports surgical management of metastatic disease if possible, and occasionally even surgical management of the primary tumor in the setting of widespread metastases. In this review, we highlight the evolving surgical management of local and metastatic PNETs.

Reprint of: The Diagnostic and Prognostic Utility of Incorporating DAXX, ATRX, and Alternative Lengthening of Telomeres (ALT) to the Evaluation of Pancreatic Neuroendocrine Tumors (PanNETs)

Pancreatic neuroendocrine tumors (PanNETs) are a heterogeneous group of neoplasms with increasing incidence and an ill-defined pathobiology. Although many PanNETs are indolent and remain stable for years, a subset may behave aggressively and metastasize widely. Thus, the increasing and frequent detection of PanNETs presents a treatment dilemma. Current prognostic systems are susceptible to interpretation errors, sampling issues, and do not accurately reflect the clinical behavior of these neoplasms. Hence, additional biomarkers are needed to improve the prognostic stratification of patients diagnosed with a PanNET. Recent studies have identified alterations in death domain-associated protein 6 (DAXX) and alpha-thalassemia/mental retardation X-linked (ATRX), as well as alternative lengthening of telomeres (ALT), as promising prognostic biomarkers. This review summarizes the identification, clinical utility, and specific nuances in testing for DAXX/ATRX by immunohistochemistry and ALT by telomere-specific fluorescence in situ hybridization in PanNETs. Furthermore, a discussion on diagnostic indications for DAXX, ATRX, and ALT status is provided to include the distinction between PanNETs and pancreatic neuroendocrine carcinomas (PanNECs), and determining pancreatic origin for metastatic neuroendocrine tumors in the setting of an unknown primary.

The diagnostic and prognostic utility of incorporating DAXX, ATRX, and alternative lengthening of telomeres to the evaluation of pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PanNETs) are a heterogeneous group of neoplasms with increasing incidence and an ill-defined pathobiology. Although many PanNETs are indolent and remain stable for years, a subset may behave aggressively and metastasize widely. Thus, the increasing and frequent detection of PanNETs presents a treatment dilemma. Current prognostic systems are susceptible to interpretation errors, sampling issues, and do not accurately reflect the clinical behavior of these neoplasms. Hence, additional biomarkers are needed to improve the prognostic stratification of patients diagnosed with a PanNET. Recent studies have identified alterations in death domain-associated protein 6 (DAXX) and alpha-thalassemia/mental retardation X-linked (ATRX), as well as alternative lengthening of telomeres (ALT), as promising prognostic biomarkers. This review summarizes the identification, clinical utility, and specific nuances in testing for DAXX/ATRX by immunohistochemistry and ALT by telomere-specific fluorescence in situ hybridization in PanNETs. Furthermore, a discussion on diagnostic indications for DAXX, ATRX, and ALT status is provided to include the distinction between PanNETs and pancreatic neuroendocrine carcinomas (PanNECs), and determining pancreatic origin for metastatic neuroendocrine tumors in the setting of an unknown primary.

Intraoperative selective arterial calcium injection test to confirm complete resection of a proinsulinoma

Proinsulinoma is a subtype of insulinoma that is surgically curable, but localization can be difficult as these tumors are typically too small to be visualized by imaging. We report the case of a 53-year-old woman referred to our hospital with dizziness and headache. Her blood glucose level was 46 mg/dl and Whipple’s triad was present. Although her immunoreactive insulin level during hypoglycemia was in the normal range (5.0 μU/ml), the proinsulin level was elevated (408 pmol/l). Imaging examinations showed no evidence of pancreatic tumor. A preoperative selective arterial calcium injection (SACI) test showed excessive insulin secretion in the splenic artery region, which localized the proinsulinoma to the body or tail of the pancreas, and laparoscopic spleen-preserving distal pancreatectomy was performed. Intraoperative SACI test performed after tumor removal did not show excessive insulin secretion. The intraoperative SACI test appears to be useful for localization and for confirming complete resection of proinsulinoma.

5-Azacytidine Inhibits the Activation of Senescence Program and Promotes Cytotoxic Autophagy during Trdmt1-Mediated Oxidative Stress Response in Insulinoma β-TC-6 Cells

5-Azacytidine (5-azaC), a methyltransferase inhibitor and anticancer drug, can promote several cellular stress responses such as apoptosis, autophagy, and senescence. The action of 5-azaC is complex and can be modulated by dose, time of treatment, and co-administration with oxidants. Insulinoma is a rare pancreatic neuroendocrine tumor with limited chemotherapeutic options. In the present study, two cellular models of insulinoma were considered, namely NIT-1 and β-TC-6 mouse cells, to evaluate the effects of 5-azaC post-treatment during hydrogen peroxide-induced oxidative stress. 5-azaC attenuated the development of oxidant-induced senescent phenotype in both cell lines. No pro-apoptotic action of 5-azaC was observed in cells treated with the oxidant. On the contrary, 5-azaC stimulated an autophagic response, as demonstrated by the increase in phosphorylated eIF2α and elevated pools of autophagic marker LC3B in oxidant-treated β-TC-6 cells. Notably, autophagy resulted in increased necrotic cell death in β-TC-6 cells with higher levels of nitric oxide compared to less affected NIT-1 cells. In addition, 5-azaC increased levels of RNA methyltransferase Trdmt1, but lowered 5-mC and m⁶A levels, suggesting Trdmt1 inhibition. We postulate that the 5-azaC anticancer action may be potentiated during oxidative stress conditions that can be used to sensitize cancer cells, at least insulinoma cells, with limited drug responsiveness.

Pancreatic neuroendocrine tumor with ectopic adrenocorticotropic hormone syndrome: a case report and 5-year follow-up

Pancreatic neuroendocrine tumors (P-NETs) secreting ectopic adrenocorticotropic hormones (ACTH) are rare and often delayed in diagnosis due to their atypical clinical characteristics. Here, we describe a case of P-NET in the pancreatic tail. The tumor had metastasized to the liver and secreted gastrin and ACTH. A 60-year-old female patient was diagnosed with gastrinoma in the pancreatic tail with liver metastases in 2015. After 3 months, the patient presented refractory hypokalemia and thyroid dysfunction. The final diagnosis was P-NET with ectopic ACTH syndrome (EAS). After cytoreductive surgery and the use of long-acting somatostatin analogs, plasma potassium levels and thyroid function were effectively corrected. Although Sandostatin LAR^® Depot and proton pump inhibitors (PPIs) were used throughout the follow-up period, the tumor relapsed 4 years later. After aggressive treatment, including right hepatectomy, microwave coagulation of the left liver, and cholecystectomy, the tumor returned 4 months later. Finally, the patient underwent three hepatic artery embolizations and 12 courses of CAPTEM regimen chemotherapy. The markers of disease were almost maintained in the normal ranges until now. We have followed up on this case for more than 5 years. A timely and comprehensive examination of hormones and immunohistochemistry is essential. The prognosis of P-NET is poor. Regular long-term follow-up and the application of combined therapies are helpful to control the disease and improve the prognosis.

Case Report: Hypoglycemia Due to Metastatic Insulinoma in Insulin-Dependent Type 2 Diabetes Successfully Treated With 177 Lu-DOTATATE

We describe a 96-year-old man with insulin-dependent type 2 diabetes mellitus who, despite insulin cessation, presented with recurrent hypoglycemia associated with confirmed inappropriate endogenous hyperinsulinemia. ⁶⁸Ga-DOTATATE-PET/CT scans demonstrated increased uptake in the pancreatic tail with multiple large intensely active liver metastases. Liver biopsy confirmed the diagnosis of well-differentiated metastatic neuroendocrine tumor. He was unsuitable for surgical resection and long-acting somatostatin analog therapy was ineffective. Subsequent management with four cycles of Lutate [177-Lutetium-DOTA⁰-Tyr³-octreotate (¹⁷⁷Lu-DOTATATE)] resulted in resolution of hypoglycemia and ongoing clinical, biochemical, and radiological response 6 years after. This case is unique due to not only the paradoxical entity of insulinoma in insulin-dependent diabetes but also the positive sustained outcome after ¹⁷⁷Lu-DOTATATE, given that unresectable metastatic insulinoma carries a poor prognosis. We review published cases of metastatic insulinoma in patients with diabetes mellitus as well as the literature to-date investigating efficacy and safety of Lutate therapy in metastatic insulinoma.

Updated Principles of Surgical Management of Pancreatic Neuroendocrine Tumours (pNETs): What Every Surgeon Needs to Know

Pancreatic neuroendocrine tumours (pNETs) represent 1 to 2% of all pancreatic neoplasm with an increasing incidence. They have a varied clinical, biological and radiological presentation, depending on whether they are sporadic or genetic in origin, whether they are functional or non-functional, and whether there is a single or multiple lesions. These pNETs are often diagnosed at an advanced stage with locoregional lymph nodes invasion or distant metastases. In most cases, the gold standard curative treatment is surgical resection of the pancreatic tumour, but the postoperative complications and functional consequences are not negligible. Thus, these patients should be managed in specialised high-volume centres with multidisciplinary discussion involving surgeons, oncologists, radiologists and pathologists. Innovative managements such as "watch and wait" strategies, parenchymal sparing surgery and minimally invasive approach are emerging. The correct use of all these therapeutic options requires a good selection of patients but also a constant update of knowledge. The aim of this work is to update the surgical management of pNETs and to highlight key elements in view of the recent literature.

What Are the Place and Modalities of Surgical Management for Pancreatic Neuroendocrine Neoplasms? A Narrative Review

Pancreatic neuroendocrine neoplasms (panNENs) are a heterogeneous group of tumors derived from cells with neuroendocrine differentiation. They are considered malignant by default. However, their outcomes are variable depending on their presentation in the onset of hereditary syndromes, hormonal secretion, grading, and extension. Therefore, although surgical treatment has long been suggested as the only treatment of pancreatic neuroendocrine neoplasms, its modalities are an evolving landscape. For selected patients (small, localized, non-functional panNENs), a "wait and see" strategy is suggested, as it is in the setting of multiple neuroendocrine neoplasia type 1, but the accurate size cut-off remains to be established. Parenchyma-sparring pancreatectomy, aiming to limit pancreatic insufficiency, are also emerging procedures, which place beyond the treatment of insulinomas and small non-functional panNENs (in association with lymph node picking) remains to be clarified. Furthermore, giving the fact that the liver is generally the only metastatic site, surgery keeps a place of choice alongside medical therapies in the treatment of metastatic disease, but its modalities and extensions are still a matter of debate. This narrative review aims to describe the current recommended surgical management for pancreatic NENs and controversies in light of the actual recommendations and recent literature.

A critical analysis of laparoscopic and open approaches to sporadic pancreatic insulinoma resection in the modern era

BACKGROUND

A single center experience with sporadic pancreatic insulinoma was analyzed to develop an algorithm for modern surgical management.

METHODS

Thirty-four patients undergoing surgery from 2001 to 2019 were reviewed.

RESULTS

The majority underwent enucleation (10 laparoscopic, 15 open). Laparoscopy was performed in 22 patients with conversion to open in 11, mostly related to the proximity of the tumor to the pancreatic duct (n = 4). Tumors on the anterior and posterior surface of the pancreas in all anatomic locations were completed with laparoscopic enucleation. Overall, the clinically-relevant postoperative pancreatic fistula (CR-POPF) rate was 21%, with no difference between laparoscopic versus open enucleation (10% vs 20%, p = 0.50) or enucleation versus resection (16% vs 33%, p = 0.27). Laparoscopic enucleation had shorter median hospital length of stay (LOS) compared with open (4 vs 7 days, p = 0.02).

CONCLUSIONS

Laparoscopic enucleation does not increase the CR-POPF risk and provides an advantage with a shorter hospital LOS in select patients. Tumor location and relationship to the pancreatic duct guide surgical decision-making. These findings highlight tumor-specific criteria that would benefit from a minimally invasive approach.

Long-term morbidity and mortality in patients diagnosed with an insulinoma

OBJECTIVE

Insulinomas are rare functional pancreatic neuroendocrine tumours. As previous data on the long-term prognosis of insulinoma patients are scarce, we studied the morbidity and mortality in the Finnish insulinoma cohort.

DESIGN

Retrospective cohort study.

METHODS

Incidence of endocrine, cardiovascular, gastrointestinal and psychiatric disorders, and cancers was compared in all the patients diagnosed with an insulinoma in Finland during 1980-2010 (n = 79, including two patients with multiple endocrine neoplasia type 1 syndrome), vs 316 matched controls, using the Mantel-Haenszel method. Overall survival was analysed with Kaplan-Meier and Cox regression analyses.

RESULTS

The median length of follow-up was 10.7 years for the patients and 12.2 years for the controls. The long-term incidence of atrial fibrillation (rate ratio (RR): 2.07 (95% CI: 1.02-4.22)), intestinal obstruction (18.65 (2.09-166.86)), and possibly breast (4.46 (1.29-15.39) and kidney cancers (RR not applicable) was increased among insulinoma patients vs controls, P < 0.05 for all comparisons. Endocrine disorders and pancreatic diseases were more frequent in the patients during the first year after insulinoma diagnosis, but not later on. The survival of patients with a non-metastatic insulinoma (n = 70) was similar to that of controls, but for patients with distant metastases (n = 9), the survival was significantly impaired (median 3.4 years).

CONCLUSIONS

The long-term prognosis of patients with a non-metastatic insulinoma is similar to the general population, except for an increased incidence of atrial fibrillation, intestinal obstruction, and possibly breast and kidney cancers. These results need to be confirmed in future studies. Metastatic insulinomas entail a markedly decreased survival.

Diagnostic and Interventional Role of Endoscopic Ultrasonography for the Management of Pancreatic Neuroendocrine Neoplasms

Pancreatic neuroendocrine neoplasms (PanNENs) are relatively rare, but their incidence has increased significantly in the last decades. Precise diagnosis and prognostic stratification are crucial for proper patient management. Endoscopic ultrasound (EUS) is the modality of choice for diagnosis of solid pancreatic tumors, showing a higher tumor detection rate than other imaging modalities, especially for small size lesions. EUS also serves as a guide for preoperative sampling and other interventions. EUS-tissue acquisition is a safe and highly accurate technique for cyto/histological diagnosis of PanNENs with a well-demonstrated correlation between Ki-67 proliferation index values and tumor grading on EUS and surgical specimens according to the WHO 2017 classification. Furthermore, the possibility of a preoperative EUS-guided fine needle tattooing or fiducial markers placement may help the surgeon to locate small and deep tumors, thus avoiding formal pancreatic resections in favor of parenchymal-sparing surgery. Finally, locoregional ablative treatments using either ethanol injection or radiofrequency ablation have been proposed in recent studies with promising results in order to control symptoms or reduce tumor burden in selected patients unfit for surgery with functioning or non-functioning PanNENs. This article review highlights the current role of EUS in PanNENs management, focusing on the present and future applications of EUS-guided interventions.

Carcinoid Syndrome and Hyperinsulinemic Hypoglycemia Associated with Neuroendocrine Neoplasms: A Critical Review on Clinical and Pharmacological Management

The carcinoid syndrome (CS) and hyperinsulinemic hypoglycemia (HH) represent two of the most common clinical syndromes associated with neuroendocrine neoplasms (NENs). The former is mainly related to the serotonin secretion by a small bowel NEN, whereas the latter depends on an insulin hypersecretion by a pancreatic insulinoma. Both syndromes/conditions can affect prognosis and quality of life of patients with NENs. They are often diagnosed late when patients become strongly symptomatic. Therefore, their early detection and management are a critical step in the clinical management of NEN patients. A dedicated and experienced multidisciplinary team with appropriate therapeutic strategies is needed and should be encouraged to optimize clinical outcomes. This review aims to critically analyze clinical features, evidence and treatment options of CS and HH and therefore to improve their management.

Clinical aspects of multiple endocrine neoplasia type 1

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

Clinical characteristics and incidence of glucose metabolism disorders during the follow-up of surgically treated insulinomas

PURPOSE

Insulinomas are pancreatic endocrine tumors characterized by hypoglycemia resulting from hypersecretion of insulin. The long-term impact of surgical treatment of insulinomas, particularly the risk of glucose metabolism disorders, remains largely unknown.

METHODS

We retrospectively evaluated all patients with insulinoma submitted to surgery at Centro Hospitalar Universitário de São João (Porto, Portugal) between 1980 and 2016. We evaluated baseline characteristics of patients at presentation, imaging evaluation, surgical treatment, characteristics of the tumors, perioperative complications, disease remission, and long-term follow-up and metabolic outcomes.

RESULTS

Twenty-eight patients with insulinomas submitted to surgical treatment were included. Sixty-one percent were female, and the average age was 46.4 years. The most reported symptoms were confusion (72%) and diaphoresis (56%). The most used imaging technique was abdominal CT (72%), and the test with the highest percentage of positive results was endoscopic ultrasound (80%). The most used surgical procedure was partial pancreatic resection (71%). The mean tumor diameter was 2.1 cm and 11% of the tumors had lymph node involvement at diagnosis. Pancreatic fistula was the most common postoperative acute complications (21%). After surgery, patients were followed for a median time of 80 months (25th-75th percentile: 20-148 months). Eight patients (32%) developed glucose metabolism disorders (seven developed diabetes and one prediabetes). One of these patients developed albuminuria, and no macrovascular complications were observed during the follow-up.

CONCLUSIONS

Disorders of glucose metabolism are a frequent complication during follow-up of surgically treated insulinomas. The prevention, early diagnosis, and treatment of diabetes should be a priority in the follow-up of these patients.

Malignant Insulinoma: A Rare Form of Neuroendocrine Tumor

INTRODUCTION

Due to the rarity of malignant insulinoma, a lack of the literature describing factors affecting outcomes exists. Our aim was to review malignant insulinoma incidence, characteristics and survival trends.

METHODS

We identified all patients with malignant insulinoma in the SEER registries from 1973 to 2015. Incidence, neoplasm characteristics and factors affecting cancer-specific survival (CSS) were described.

RESULTS

A total of 121 patients were identified. The crude annual overall incidence was low (range 0.0-0.27 cases per million person years). The largest proportion had localized disease (40%), while 16% had regional disease, 39% distant metastatic disease, and stage was unreported in 5%. Most neoplasms were in the body/tail of the pancreas, followed by the head of the pancreas. Grade was reported in 40% of patients; only a single patient reported as having grade IV with the remainder all grades I/II. Surgical resection was performed in 64% of patients. Within surgical patients, the median primary neoplasm size was 1.8 cm. Regional lymph nodes were examined in 57.1% of surgical patients, while 34% of examined nodes were positive. The median CSS was 183 months. On multivariable analysis, surgical resection, male sex and absence of metastatic disease were associated with superior survival.

CONCLUSION

While the greatest proportion of patients with malignant insulinoma present with localized disease, regional lymph node involvement was found in 34% of whose nodes were tested. Further studies are needed to assess the role of lymph node dissection in improving survival and preventing recurrence given the observed frequency of lymph node involvement.

Usefulness of selective arterial calcium injection tests for functional pancreatic neuroendocrine tumors

The selective arterial calcium injection (SACI) test is useful for patients with functional pancreatic neuroendocrine tumors (F-PNETs). This study evaluated which patients with F-PNETs would benefit from the SACI test. We retrospectively analyzed the preoperative findings of patients on computed tomography (CT), magnetic resonance imaging (MRI), CT angiography (CTA), and the SACI test. Fourteen patients who underwent pancreatectomy between January 1997 and September 2016 for F-PNETs were evaluated. We classified these patients into groups A, B, and C; group A, one tumor detected by either CT or MRI; group B, multiple tumors detected; and group C, the tumor location was accordant on CT, MRI, and CTA, but the SACI test revealed another tumor. In group A, the tumor was also detected by CTA and the SACI test was positive on calcium injection. In group B, the focus tumor among the multiple tumors was detected by the SACI test. In group C, another tumor was identified by the SACI test, whose location was different from that detected using CT and MRI. The SACI test is more useful for multiple F-PNETs on CT or MRI. If CT or MRI detects a single tumor, the SACI test or CTA may be unnecessary.

Endoscopic ultrasound-guided radiofrequency ablation: An effective and safe alternative for the treatment of benign insulinoma

BACKGROUND

Insulinomas are usually benign, small-sized, well-encapsulated and often solitary pancreatic tumors. Currently, enucleation is the treatment of choice for sporadic solitary insulinoma if diameter is less than 2cm and the structural integrity of the pancreatic duct can be maintained. However, the procedure has a risk of postoperative complications, and especially of pancreatic fistula. There is growing interest in endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) as an effective and less invasive alternative treatment for benign sporadic insulinoma.

METHOD

We retrospectively analyzed the efficacy and safety of EUS-RFA in four patients with benign localized insulinoma treated in our tertiary care center between June 2018 and November 2019. EUS-RFA was performed with a EUS-guided RFA 19-gauge needle electrode (Starmed; Taewoong Medical, Seoul, South Korea) that released energy at 50W up to 100 Ohms impedance.

RESULTS

The series comprised three women and one man, with a median age of 58 years (range 52-82 years). Mean tumor size was 12mm. Although three of the four patients would have been eligible for surgery, EUS-RFA was proposed to them. Symptomatic and biological improvement occurred immediately, generally straight after the procedure, in all patients, and no serious complications were observed. During the mean follow-up period of 22 months, no symptom recurrence was observed.

CONCLUSIONS

This preliminary report in 4 patients showed that EUS-RFA was an effective and relatively safe alternative treatment, devoid of major complications, for benign sporadic insulinoma. Larger-scale prospective multicenter studies are, however, needed to confirm the long-term effectiveness and safety of this novel technique.

Insulinoma presenting with postprandial hypoglycemia and a low body mass index: A case report

BACKGROUND

Insulinomas are the most common type of functioning endocrine neoplasms of the pancreas presenting hypoglycemic symptoms. Patients characteristically develop symptoms while fasting, but some patients have reported symptoms only in the postprandial state. Repeated and prolonged hypoglycemic episodes can reduce the awareness of adrenergic symptoms, and patients may have amnesia, which delays diagnosis.

CASE SUMMARY

We describe a case of a 24-year-old underweight patient who showed hypoglycemic symptoms for almost 6 years. Although patients with insulinoma characteristically develop symptoms while fasting, this young man had hypoglycemic symptoms up to one hour postprandially, especially after high-sugar meals and after physical activity. The fasting tests and imaging methods performed at local hospitals were evaluated as negative for abnormal results. However, brown adipose tissue exhibited increased metabolic activity, and some muscle groups had histological changes as indicated by positron emission tomography with 2-deoxy-2-[fluorine-18]fluoro-D-glucose integrated with computed tomography. Glycogen deficiency was also histologically confirmed. The patient’s symptoms progressed over the years and occurred more frequently, i.e., several times a month, and the patient had reduced awareness of adrenergic symptoms. The follow-up fasting test was positive, and the imaging results showed a tumor in the head of the pancreas. The patient underwent laparotomy with enucleation of the insulinoma.

CONCLUSION

Weight gain and fasting hypoglycemia are not necessarily characteristics of insulinoma. In prolonged cases, adrenergic symptoms can be suppressed.

Surgical Management of Neuroendocrine Tumours of the Pancreas

Neuroendocrine tumours of the pancreas (pNET) are rare, accounting for 1-2% of all pancreatic neoplasms. They develop from pancreatic islet cells and cover a wide range of heterogeneous neoplasms. While most pNETs are sporadic, some are associated with genetic syndromes. Furthermore, some pNETs are 'functioning' when there is clinical hypersecretion of metabolically active peptides, whereas others are 'non-functioning'. pNET can be diagnosed at a localised stage or a more advanced stage, including regional or distant metastasis (in 50% of cases) mainly located in the liver. While surgical resection is the cornerstone of the curative treatment of those patients, pNET management requires a multidisciplinary discussion between the oncologist, radiologist, pathologist, and surgeon. However, the scarcity of pNET patients constrains centralised management in high-volume centres to provide the best patient-tailored approach. Nonetheless, no treatment should be initiated without precise diagnosis and staging. In this review, the steps from the essential comprehensive preoperative evaluation of the best surgical approach (open versus laparoscopic, standard versus sparing parenchymal pancreatectomy, lymphadenectomy) according to pNET staging are analysed. Strategies to enhance the short- and long-term benefit/risk ratio in these particular patients are discussed.

Surgical management of insulinomas at the Azerbaijan Medical University: a retrospective study of 21 cases over a 10-year period

Background/aim

This study represents the first report that evaluates the experience gathered from diagnosis, surgical treatment and outcome of insulinoma patients from Azerbaijan.

Materials and methods

We retrospectively review of insulinoma patients for a 10-year period. Collected data included patient demographics, laboratory and imaging tests, detailed surgical reports, histopathological examination of resected specimens, and clinical follow-up.

Results

Twenty-one insulinoma patients were identified. Male patients comprised 52.4%; mean age was 44 years. Mean time to diagnosis was 14 months; 61% patients had ≥3 medical referrals due to hypoglycemia-related symptoms. Diagnosis sensitivity of CT, MRI and US was 85%, 80%, and 55%, respectively. The mean glucose, insulin, C-peptide levels were 35.7 ± 9.5 mg/dL, 33.5 ± 21.9 µU/mL, and 3.74 ± 1.88 ng/mL, respectively. Pancreatic head and tail were the most frequent tumor locations; mean tumor size was 1.5 ± 0.7 cm. No statistical association was found between the tumor size and preoperative glucose, C-peptide and insulin levels. Distal pancreatectomy and enucleation were the most common surgical procedures. Local tumor recurrence rate was 14%. There was no mortality.

Conclusions

To prevent delayed diagnoses, physicians should be familiar with the typical symptoms of these rare tumors.

Comparison of benign and malignant insulinoma

BACKGROUND

How malignant insulinomas present relative to benign insulinomas is unknown.

METHODS

A single-institution retrospective study identified patients with insulinoma. Malignancy was defined by distant metastases, positive lymph node(s), T stage of 4, direct invasion into surrounding peripancreatic tissue, or presence of lymphovascular invasion. Wilcoxon Rank Sum tests and Kaplan-Meier analysis were used.

RESULTS

A total of 311 patients were identified: 51 malignant and 260 benign. Patients with malignant insulinoma presented with higher levels of insulin, proinsulin, and c-peptide. Malignant lesions were larger: 4.2 ± 3.2 vs 1.8 ± 0.8 cm in benign lesions, p < 0.01. Overall survival at 5 years was 66.8% vs 95.4% for malignant and benign insulinoma respectively, p < 0.01.

CONCLUSIONS

Larger size of insulinoma and increased serum β-cell polypeptide concentrations were associated with malignancy. Malignant insulinoma has poorer survival. Further work-up to rule out malignancy may be indicated for larger pancreatic lesions and for patients with higher pre-operative insulin and pro-insulin.

Alternative Lengthening of Telomeres and Differential Expression of Endocrine Transcription Factors Distinguish Metastatic and Non-metastatic Insulinomas

Insulin-producing pancreatic neuroendocrine tumors (PanNETs)/insulinomas are generally considered to be indolent tumors with an excellent prognosis after complete resection. However, some insulinomas have a poor prognosis due to relapses and metastatic disease. Recently, studies in non-functional PanNETs indicated that behavior can be stratified according to alpha- and beta-cell differentiation, as defined by expression of the transcription factors ARX and PDX1, respectively. It is unknown whether similar mechanisms play a role in insulinomas. Therefore, we determined ARX and PDX1 expression in a cohort of 35 sporadic primary insulinomas and two liver metastases of inoperable primary insulinomas. In addition, WHO grade and loss of ATRX or DAXX were determined by immunohistochemistry, and alternative lengthening of telomeres (ALT) and CDKN2A status by fluorescence in situ hybridization. These findings were correlated with tumor characteristics and clinical follow-up data. In total, five out of 37 insulinoma patients developed metastatic disease. Metastatic insulinomas were all larger than 3 cm, whereas the indolent insulinomas were smaller (p value < 0.05). All three primary insulinomas that metastasized showed ARX expression, 2/3 showed ALT, and 1/3 had a homozygous deletion of CDKN2A as opposed to absence of ARX expression, ALT, or CDKN2A deletions in the 32 non-metastatic cases. The two liver metastases also showed ARX expression and ALT (2/2). The presence of ARX expression, which is usually absent in beta-cells, and genetic alterations not seen in indolent insulinomas strongly suggest a distinct tumorigenic mechanism in malignant insulinomas, with similarities to non-functional PanNETs. These observations may inform future follow-up strategies after insulinoma surgery.

Usefulness of the index calculated as the product of levels of fasting plasma glucose and hemoglobin A1c for insulinoma screening

Hypoglycemia is the major symptom of insulinoma. Chronic and recurrent hypoglycemia leads to the disappearance of autonomic symptoms and persistence of non-specific symptoms alone, possibly contributing to the delayed diagnosis of insulinoma and accounting for several undiagnosed cases. We previously reported the usefulness of hemoglobin A1c (HbA1c) and glycated albumin as markers for early insulinoma screening; however, their diagnostic prediction performance and diagnostic performance were not satisfactory. We hypothesized that the product of fasting plasma glucose (FPG) and HbA1c levels (FPG × HbA1c index) is low in insulinoma, and this index may be a useful marker for screening. This cross-sectional multicenter study compared 82 insulinoma patients with 100 age-, sex-, and body mass index-matched controls with normal glucose tolerance based on 75-g oral glucose tolerance test. The FPG × HbA1c index was significantly lower in the insulinoma group than in the control group. Receiver operating curve analysis showed that the optimal cutoff point of the FPG × HbA1c index to diagnose insulinoma was 447.1, and the area under the curves (AUCs) of the FPG × HbA1c index and HbA1c were 0.998 and 0.966, respectively. The AUC of the index was significantly higher than that of HbA1c (p = 0.010). Conversely, no significant difference existed between the AUC of the FPG × HbA1c index and that of the FPG/fasting immunoreactive insulin index. Thus, in apparently healthy population, the product of FPG and HbA1c yields a useful index for insulinoma screening in terms of accuracy and versatility.

Quand et avec quelles conséquences opérer une tumeur neuroendocrine du pancréas ou du grêle ?

Les tumeurs neuroendocrines (TNE) sont des tumeurs rares et peuvent survenir dans tout le tube digestif. On distingue les tumeurs fonctionnelles associées à des symptômes secondaires à l’activité sécrétoire de la tumeur et les tumeurs non fonctionnelles. Tout patient présentant une TNE doit être discuté en RCP RENATEN. Concernant les TNE duodénopancréatiques sporadiques, la chirurgie est nécessaire devant une TNE fonctionnelle ainsi que devant une TNE non fonctionnelle de plus de 2 cm, associées ou non à un retentissement canalaire. Pour les tumeurs supposées peu ou pas agressives, il sera toujours privilégié une stratégie d’épargne parenchymateuse afin d’éviter l’insuffisance pancréatique endocrine et exocrine. Concernant les TNE du grêle, la chirurgie doit être systématiquement envisagée, y compris en cas de métastases ou de carcinose associée afin d’éviter une complication mécanique telle qu’une occlusion. Un curage ganglionnaire comportant au minimum huit ganglions doit être effectué. Ce curage doit être large tout en préservant une vascularisation suffisante afin d’éviter la survenue d’un syndrome de grêle court.

How to perform EUS-guided tattooing?

Recently, we introduced a series of papers describing on how to perform certain techniques and controversies in EUS. In the first paper, "What should be known before performing EUS examinations, Part I," the authors discussed clinical information and whether other imaging modalities should be needed before embarking in EUS examination. In Part II, some technical controversies on how EUS is performed are discussed from different points of view by providing the relevant available evidence. Herewith, we describe on how to perform EUS-guided fine needle tattooing (FNT) in daily practice. The aim of this paper is to discuss pros and cons for several issues including historical remarks, injecting material, technical approach, and how to perform EUS-FNT including argues in favor and against.

Surgical management of pancreatic neuroendocrine tumors: an introduction

Introduction: Neuroendocrine tumors of the pancreas (pNETs) represent only 1% to 2% of all pancreatic neoplasms. These tumors can be classified as functional or nonfunctional tumors; as sporadic or from a genetic origin; as neuroendocrine neoplasms or carcinoma. Over the last decade, diagnosis of pNETs has increased significantly mainly due to the widespread use of cross-sectional imaging. Those tumors are usually associated with a good prognosis. Surgery, the only curative option for those patients, should always be discussed, ideally in a multidisciplinary team setting.Areas covered: We discuss i), the preoperative management of pNETs and the importance of accurate diagnosis, localization, grading and staging with computed tomography, magnetic resonance imaging, endoscopic ultrasound, and nuclear medicine imaging; ii), surgical indications and iii), the surgical approach (standard pancreatectomy vs pancreatic-sparing surgery).Expert opinion: The treatment option of all patients presenting with pNETs should be discussed in a multidisciplinary team setting with surgeon's experienced in both pancreatic surgery and neuroendocrine tumor management. A complete preoperative imaging assessment - morphological and functional - must be performed. Surgery is usually recommended for functional pNETs, nonfunctional pNETs >2 cm (nf-pNETs) or for symptomatic nf-pNETs.

Endogenous hyperinsulinism: diagnostic and therapeutic difficulties

Endogenous hyperinsulinism is an abnormal clinical condition that involves excessive insulin secretion, related in 55% of cases to insulinoma. Other causes are possible such as islet cell hyperplasia, nesidioblastosis or antibodies to insulin or to the insulin receptor. Differentiation between these diseases may be difficult despite the use of several morphological examinations. We report six patients operated on for endogenous hyperinsulinism from 1^st January 2000 to 31^st December 2015. Endogenous hyperinsulinism was caused by insulinoma in three cases, endocrine cells hyperplasia in two cases and no pathological lesions were found in the last case. All patients typically presented with adrenergic and neuroglycopenic symptoms with a low blood glucose level concomitant with high insulin and C-peptide levels. Computed tomography showed insulinoma in one case out of two. MRI was carried out four times and succeeded to locate the lesion in the two cases of insulinoma. Endoscopic ultrasound showed one insulinoma and provided false positive findings three times out of four. Intra operative ultrasound succeeded to localize the insulinoma in two cases but was false positive in two cases. Procedures were one duodenopancreatectomy, two left splenopancreatectomy and two enucleations. For the sixth case, no lesion was radiologically objectified. Hence, a left blind pancreatectomy was practised but the pathological examination showed normal pancreatic tissue. Our work showed that even if morphological examinations are suggestive of insulinoma, other causes of endogenous hyperinsulinism must be considered and therefore invasive explorations should be carried out.

Open and minimally invasive pancreatic neoplasms enucleation: a systematic review

BACKGROUND

Pancreatic enucleation (pEN) as parenchyma-sparing procedure for small pancreatic neoplasms is quickly becoming the most common surgical option in such setting. Nowadays, pEN is frequently carried out through a minimally invasive approach either laparoscopic or robotic. Its impact on overall perioperative complications and pancreatic fistula (POPF) is still under evaluation. The scope of our systematic review is to assess pEN's perioperative outcomes and to evaluate the effect of the minimally invasive techniques over POPF and other surgical complications.

METHODS

We performed a systematic literature search (time-frame January 1999-September 2018), considering exclusively those studies which included at least 5 cases of either open or minimally invasive pEN. Data regarding postoperative outcome and POPF were extracted and analyzed. We defined postoperative morbidities by the Clavien-Dindo classification while POPF according to the International Study Group of Pancreatic Fistula (ISGPF) definition.

RESULTS

Sixty-three studies met the criteria selected, accounting for a study population of 2485 patients. 27.7% had a minimally invasive pEN. The overall postoperative morbidity rate was 46.1% with 11.9% rated as severe (Clavien-Dindo ≥ 3). Mortality rate was 0.69%. The minimally invasive approach to pEN led to a statistically significant reduction of both the overall POPF rate (28.7% vs. 45.9%, p < 0.001), and clinically significant B-C POPF (p < 0.027). The postoperative overall morbidity rate was clearly in favor of the minimally invasive approach (27.6% vs. 55.2%, p < 0.001).

CONCLUSIONS

Our review confirms that pEN is a safe and feasible technique for the treatment of small benign or low-grade pancreatic neoplasms and it can be implemented with an acceptable morbidity rate along with low mortality. The minimally invasive approach is gaining widespread acceptance due to its supposed non-inferiority compared with the traditional open approach. In our review, it showed to be even better in terms of POPF incidence rate and short-term postoperative outcome. Still, such data need to be corroborated by randomized clinical trials.

Gastroenteropancreatic neuroendocrine tumors: Role of surgery

Natural history of gastroenteropancreatic (GEP) Neuroendocrine tumors (NETs) is better and better known so indications of surgery are presently selective. Surgical resection, but also endoscopic resection and observation, can be proposed for gastric NETs according to presentation, size and grade. For small bowel NETs, resection is frequently needed but should obtain the best compromise between radicality and postoperative functional disorders. Appendiceal NETs are frequently diagnosed by appendectomy for appendicitis, but some patients at high risk for lymph node metastasis and recurrence should be reoperated for radical resection. Rectal NETs are often diagnosed incidentally; the smallest (<1cm) can be resected endoscopically but the most aggressive need a oncological proctectomy. Pancreatic NETs represent a wide spectrum, ranging from fully benign tumors to very aggressive ones. Insulinomas are mostly benign, responsible for incapacitating symptoms despite medical treatment, and should ideally be treated by parenchyma sparing resection, mainly enucleation. Conversely, symptoms of gastrinomas are efficiently treated medically but their resection needs an oncological approach. Nonfunctioning PNETs are more and more frequently and incidentally discovered. According to their size, presentation and patient's characteristics, they need a resection (oncological or parenchyma-sparing) or a close observation.

Distinct clinicopathological and prognostic features of insulinoma with synchronous distant metastasis

BACKGROUND

The clinicopathological and prognostic features of insulinoma with synchronous metastases are unclear. This study aimed to verify the distinct clinicopathological and prognostic features of insulinoma with synchronous distant metastasis.

METHODS

Patients with pancreatic neuroendocrine tumor (PanNET) were retrospectively enrolled and divided into cohort 1 (Fudan University Shanghai Cancer Center) and cohort 2 (Surveillance, Epidemiology, and End Results Program database). Both cohorts were further divided into three subgroups: insulinoma, nonfunctioning pancreatic neuroendocrine tumor (NF-PanNET), and non-insulinoma functioning pancreatic neuroendocrine tumor (NiF-PanNET).

RESULTS

Cohorts 1 and 2 comprised 505 and 2761 patients (1566 M0 patients and 1195 M1 patients), respectively. In cohort 1 and cohort 2 M0 subgroup, insulinoma showed longer disease-free survival, overall survival (OS), and disease-specific survival (DSS) than NiF-PanNET and NF-PanNET (not reached vs. 48 and 60months, p < 0.001; 183months vs. 87 and 109months, p < 0.001; 247months vs. 121 and 140months, p = 0.002). However, in cohort 2 M1, the mDSS for metastatic insulinoma was shorter than that for NiF-PanNET (31months vs. 61months, p = 0.045), while the mDSS and mOS were similar to those for NF-PanNET. The percentage of T1 and N0 patients was similar between the metastatic insulinoma subgroup and NiF-PanNET and NF-PanNET subgroups. The Ki-67 index and recurrence had a positive linear relationship only for NiF-PanNET and NF-PanNET (p = 0.009).

CONCLUSIONS

Insulinoma with synchronous metastasis showed clinicopathological and prognostic characteristics similar to those of NF-PanNET. Metastatic insulinoma had worse prognosis than non-insulinoma F-PanNET. These findings may help in the clinical management of metastatic insulinoma.

Usefulness of hemoglobin A1c and glycated albumin measurements for insulinoma screening: an observational case-control study

Background

Insulinoma represents hypoglycemia as a predominant symptom; the autonomic symptoms may be resolved by chronically recurrent hypoglycemia resulting in the persistence of non-specific symptoms alone. Therefore, it has been estimated that there are many patients in whom the disease takes longer to diagnose and has remained undiagnosed. Although some parameters exist for the definitive diagnosis of the disease, there are currently no indices for early screening. Indices of glycemic control, hemoglobin A1c (HbA1c), and glycated albumin (GA) may be useful for the screening of patients with insulinoma having chronic hypoglycemia because the values become low in such a condition. Because there are no articles that have reported the point, we examine the effective cutoff values of HbA1c and GA for the diagnosis of insulinoma in the present study.

Methods

In a multicenter cross-sectional study, 31 patients with insulinoma were included for comparison with 120 control subjects with normal glucose tolerance based on 75 g oral glucose tolerance tests whose characteristics were matched to the patients. The primary outcomes were optimal cutoff values of HbA1c and GA for the screening of insulinoma.

Results

HbA1c was significantly lower in the insulinoma group at 4.7 ± 0.4% compared to the healthy control group at 5.7 ± 0.3% (p < 0.001), and GA was significantly lower in the insulinoma group at 11.6 ± 1.8% compared to the healthy control group at 14.5 ± 1.0% (p < 0.001). According to a receiver operating characteristic (ROC) analysis, optimal cutoff values of HbA1c and GA for the diagnosis of insulinoma were 5.0 and 12.4%, respectively. Area under the curve values of HbA1c and GA were 0.970 and 0.929, respectively, showing no significant difference (p = 0.399).

Conclusions

In the present study, HbA1c and GA values in patients with insulinoma were significantly lower compared to the healthy controls, and effective cutoff values for screening were shown in the diagnosis of insulinoma for the first time. HbA1c and GA can be useful indices for insulinoma screening. Because malignant insulinoma have a similar diagnostic process to that of benign insulinoma, these could be useful for malignant insulinoma.

Robotic enucleation for pediatric insulinoma with MEN1 syndrome: a case report and literature review

Background

A patient with a rare pediatric insulinoma and MEN1 syndrome was treated by robotic enucleation surgery.

Case presentation

We present a case of a 9-year-old girl presenting with repeated loss of consciousness, concomitant with a pale face, palpitations, and convulsions, which had persisted for 2 years and had been aggravated during the previous 2 months. She was previously misdiagnosed with epilepsy in another hospital. We further examined her while she was hospitalized. By combining her medical history and imaging examination and lab test results, a diagnosis of insulinoma was confirmed. Sanger-directed sequencing on a peripheral blood sample revealed an MEN1 gene mutation, indicating pediatric insulinoma with MEN1 syndrome. The patient underwent minimally invasive insulinoma enucleation surgery under the Da Vinci robot-assisted system with intraoperative ultrasound (IOUS) connected. The surgery was successfully completed within 65 min, and the girl recovered well postoperatively and no longer experienced symptoms of hypoglycemia.

Conclusion

This is the first report of a case of pediatric insulinoma treated using robotic enucleation. This experience demonstrates the feasibility and safety of combining robotic surgery with the enucleation procedure as an excellent strategy for pediatric insulinoma.

Two nonsense somatic mutations in MEN1 identified in sporadic insulinomas

Insulinomas are functional pancreatic neuroendocrine tumors that cause hypoglycemia and severe morbidity. The aim of our study was to identify gene mutations responsible for tumorigenesis of sporadic insulinoma. Whole exome sequencing analysis was performed on tumors and paired peripheral blood from three patients with insulinomas. After initial analysis, somatic mutations were obtained and a deleterious protein product was further predicted by various bioinformatic programs. Whole exome sequencing identified 55 rare somatic mutations among three insulinoma patients, including MEN1 gene nonsense mutations (c. 681C>G; p.Tyr227* in exon 4 of MEN1 and c. 346G>T; p.Glu116* in exon 2 of MEN1) in two different tumor samples. The mutations resulted in a significant truncation of the protein and a non-functional gene product, which was involved in defective binding of menin to proteins implicated in genetic and epigenetic mechanisms. Our results extend the growing list of pathogenic MEN1 mutations in sporadic cases of insulinoma.

Characteristics and Outcomes of 79 Patients with an Insulinoma: A Nationwide Retrospective Study in Finland

OBJECTIVE

Insulinomas are rare pancreatic tumours. Population-based data on their incidence, clinical picture, diagnosis, and treatment are almost nonexistent. The aim of this study was to clarify these aspects in a nationwide cohort of insulinoma patients diagnosed during three decades.

DESIGN AND METHODS

Retrospective analysis on all adult patients diagnosed with insulinoma in Finland during 1980-2010.

RESULTS

Seventy-nine patients were diagnosed with insulinoma over the research period. The median follow-up from diagnosis to last control visit was one (min 0, max 31) year. The incidence increased from 0.5/million/year in the 1980s to 0.9/million/year in the 2000s (p = 0.002). The median diagnostic delay was 13 months and did not change over the study period. The mean age at diagnosis was 52 (SD 16) years. The overall imaging sensitivity improved from 39% in the 1980s to 98% in the 2000s (p < 0.001). Seventy-one (90%) of the patients underwent surgery with a curative aim, two (3%) had palliative surgery, and 6 (8%) were inoperable. There were no significant differences in the types of surgical procedures between the 1980s, 1990s, and 2000s; tumour enucleations comprised 43% of the operations, distal pancreatic resections 45%, and pancreaticoduodenectomies 12%, over the whole study period. Of the patients who underwent surgery with a curative aim, 89% had a full recovery. Postoperative complications occurred in half of the patients, but postoperative mortality was rare.

CONCLUSIONS

The incidence of insulinomas has increased during the past three decades. Despite the improved diagnostic options, diagnostic delay has remained unchanged. To shorten the delay, clinicians should be informed and alert to consider the possibility of hypoglycemia and insulinoma, when symptomatic attacks are investigated in different sectors of the healthcare system. Developing the surgical treatment is another major target, in order to lower the overall complication rate, without compromising the high cure rate of insulinomas.

When should genetic testing be performed in patients with neuroendocrine tumours?

Neuroendocrine tumours (NETs) are a heterogenous group of tumours arising from neuroendocrine cells in several sites around the body. They include tumours of the gastroenteropancreatic system, phaeochromocytoma and paraganglioma and medullary thyroid cancer. In recent years, it has become increasingly apparent that a number of these tumours arise as a result of germline genetic mutations and are inherited in an autosomal dominant pattern. The number of genes implicated is increasing rapidly. Identifying which patients are likely to have a germline mutation enables clinicians to counsel patients adequately about their future disease risk, and allows for earlier detection of at-risk patients through family screening. The institution of screening and surveillance programmes may in turn lead to a major shift in presentation patterns for some of these tumours. In this review, we examine the features which may lead a clinician to suspect that a patient may have an inherited cause of a NET and we outline which underlying conditions should be suspected. We also discuss what type of screening may be appropriate in a variety of situations.

Should the Selective Arterial Secretagogue Injection Test for Insulinoma Localization Be Evaluated at 60 or 120 Seconds?

Objective The selective arterial secretagogue injection (SASI) test is considered indispensable for the accurate localization of insulinoma. However, the optimum timing of the post-injection evaluation is controversial, as some studies recommend 60 seconds [SASI (60 seconds)] while others support 120 seconds [SASI (120 seconds)]. The aim of this study was to determine the optimum timing for the SASI test evaluation for insulinoma localization. Methods Thirteen patients with surgically proven insulinoma were studied retrospectively. For the SASI test, immunoreactive insulin (IRI) was determined at baseline and at 30, 60, 90, and 120 seconds after calcium gluconate injection. A two-fold or greater increase in IRI over the baseline value was considered positive. The localization abilities of SASI (60 seconds) and SASI (120 seconds) were then compared. Results In 13 patients, a secretagogue was injected into 40 arteries supplying the pancreas. In the SASI (60 seconds) and SASI (120 seconds), the respective findings were as follows: positive predictive value, 72.2% and 68.2%; false positive rate, 25.0% and 35.0%; and rate of positivity in the head and body/tail, 38.5% and 46.2%. When the artery with the largest change was taken as the dominant artery, the localization detection sensitivity was 76.9% for SASI (60 seconds) and 92.3% for SASI (120 seconds). The sensitivity of morphological imaging techniques for localization ranged from 61.5-91.7%. Conclusion Compared with SASI (60 seconds) or morphological imaging, the insulinoma localization ability of SASI (120 seconds) was superior. Given these findings, we believe that the IRI level should be measured at 120 seconds in the SASI test.

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

Multiple endocrine neoplasia type 1 (MEN1) is a hereditary autosomal dominant disorder associated with numerous neuroendocrine tumors (NETs). Recent advances in the management of MEN1 have led to a decrease in mortality due to excess hormones; however, they have also led to an increase in mortality from malignancy, particularly NETs. The main challenges are to localize these tumors, to select those that need therapy because of the risk of aggressive behavior and to select the appropriate therapy associated with minimal morbidity. This must be applied to a hereditary disease with a high risk of recurrence. The overall aim of management in MEN1 is to ensure that the patient remains disease- and symptom-free for as long as possible and maintains a good quality of life. Herein, we review the changes that occurred in the last 20 years in the surgical management of MEN1-associated functional and non-functional pancreatico-duodenal NETs and thymic and bronchial NETs.