UTRs and Ago-2/miR-335 Complex Restricts Amylin Translation in Insulinoma and Human Pancreatic ß-Cells.

Amylin promoter and transcriptional factors are well-established, inducible factors in the production of the main amyloidogenic pancreatic hormone, human islet amyloid peptide (hIAPP) or amylin. However, posttranscriptional mechanisms driving hIAPP expression in pancreas remain enigmatic, and hence were explored here. The translational assay revealed that both 5' and 3' untranslated regions (UTRs) of hIAPP restricted expression of the luciferase constructs only in constructs driven by the hIAPP promoter. Bioinformatics analysis revealed several putative seed sequences for a dozen micro RNAs (miRNAs) in hIAPP's 3' UTR. miR-182, miR-335, and miR-495 were the most downregulated miRNAs in stressed human islets exposed to endoplasmic reticulum (ER) or metabolic stressors, thapsigargin (TG) or high glucose (HG). Correspondingly, miR-335 mimics alone or in combination with miR-495 and miR-182 mimics significantly and potently (>3-fold) reduced hIAPP protein expression in HG-treated cultured human islets. siRNA-mediated silencing of Ago2 but not Ago1 significantly stimulated hIAPP expression and secretion from transfected, HG-treated human islets. Conversely, ectopic expression of Ago2 in hIAPP-expressing RIN-m5F cell line driven by CMV promoter reduced hIAPP intracellular protein levels. Collectively, the results point to a novel and synergistic role for hIAPP promoter, 5/3' UTRs and Ago-2/miR-335 complex in post-transcriptional regulation of hIAPP gene expression in normal and metabolically active ß-cells.

Clinicopathological Features of Pediatric Insulinoma: A Single-Centre Study.

Aims/Background: Insulinoma is an extremely rare condition in pediatric patients. This study aims to examine the pathological and clinical characteristics of pediatric insulinoma. Methods: A retrospective, single-center study was conducted involving five pediatric patients diagnosed with insulinoma. The study involved evaluating the postoperative status of the patients during follow-up and analyzing their clinical manifestations, diagnostic work-up, pathological findings, and therapeutic approaches. Results: The study cohort comprised four males and one female, aged between 4 and 9 years. Common symptoms included dizziness and fatigue. The insulinomas were located in various parts of the pancreas: two in the head, one in the neck, one in the body, and one in the tail. After undergoing subtotal pancreatectomy, four patients experienced no side effects during a follow-up period of 41 to 153 months. One patient, who underwent an incomplete pancreatic resection, required ongoing postoperative treatment with 150 mg Creon due to pancreatic enzyme deficiency. Postoperative pathological results indicated that all cases were low-grade neuroendocrine tumours, classified as grade 1 (G1) or grade 2 (G2). Two cases exhibited capsule invasion, and one case showed microvascular invasion. Despite these invasions, no recurrences or metastases have been observed to date. Conclusion: Surgical resection is a viable treatment option for pediatric insulinoma, yielding a favorable prognosis. The presence of capsular and microvascular invasions does not seem to affect the overall prognosis in these cases.

Serotonin Influences Insulin Secretion in Rat Insulinoma INS-1E Cells.

Serotonin or 5-hydroxytryptamine (5-HT) is a monoamine that plays a critical role in insulin secretion, energy metabolism, and mitochondrial biogenesis. However, the action of serotonin in insulin production and secretion by pancreatic ß cells has not yet been elucidated. Here, we investigated how exogenous nanomolar serotonin concentrations regulate insulin synthesis and secretion in rat insulinoma INS-1E cells. Nanomolar serotonin concentrations (10 and 50 nM) significantly increased insulin protein expression above the constant levels in untreated control cells and decreased insulin protein levels in the media. The reductions in insulin protein levels in the media may be associated with ubiquitin-mediated protein degradation. The levels of membrane vesicle trafficking-related proteins including Rab5, Rab3A, syntaxin6, clathrin, and EEA1 proteins were significantly decreased by serotonin treatment compared to the untreated control cells, whereas the expressions of Rab27A, GOPC, and p-caveolin-1 proteins were significantly reduced by serotonin treatment. In this condition, serotonin receptors, Gαq-coupled 5-HT2b receptor (Htr2b), and ligand-gated ion channel receptor Htr3a were significantly decreased by serotonin treatment. To confirm the serotonylation of Rab3A and Rab27A during insulin secretion, we investigated the protein levels of Rab3A and Rab27A, in which transglutaminase 2 (TGase2) serotonylated Rab3A but not Rab27A. The increases in ERK phosphorylation levels were consistent with increases in the expression of p-Akt. Also, the expression level of the Bcl-2 protein was significantly increased by 50 and 100 nM serotonin treatment compared to the untreated control cells, whereas the levels of Cu/Zn-SOD and Mn-SOD proteins decreased. These results indicate that nanomolar serotonin treatment regulates the insulin protein level but decreases this level in media through membrane vesicle trafficking-related proteins (Rab5, Rab3A, syntaxin6, clathrin, and EEA1), the Akt/ERK pathway, and Htr2b/Htr3a in INS-1E cells.

Decreased islet amyloid polypeptide staining in the islets of insulinoma patients.

Islet amyloid polypeptide (IAPP) is a factor that regulates food intake and is secreted from both pancreatic islets and insulinoma cells. Here, we aimed to evaluate IAPP immunohistochemically in islets or insulinoma cells in association with clinical characteristics. We recruited six insulinoma patients and six body mass index-matched control patients with pancreatic diseases other than insulinoma whose glucose tolerance was confirmed to be normal preoperatively. IAPP and IAPP-insulin double staining were performed on pancreatic surgical specimens. We observed that the IAPP staining level and percentage of IAPP-positive beta cells tended to be lower (p = 0.1699) in the islets of insulinoma patients than in those of control patients, which might represent a novel IAPP expression pattern under persistent hyperinsulinemia and hypoglycemia.

Implications of noncoding regulatory functions in the development of insulinomas.

Insulinomas are rare neuroendocrine tumors arising from pancreatic ß cells, characterized by aberrant proliferation and altered insulin secretion, leading to glucose homeostasis failure. With the aim of uncovering the role of noncoding regulatory regions and their aberrations in the development of these tumors, we coupled epigenetic and transcriptome profiling with whole-genome sequencing. As a result, we unraveled somatic mutations associated with changes in regulatory functions. Critically, these regions impact insulin secretion, tumor development, and epigenetic modifying genes, including polycomb complex components. Chromatin remodeling is apparent in insulinoma-selective domains shared across patients, containing a specific set of regulatory sequences dominated by the SOX17 binding motif. Moreover, many of these regions are H3K27me3 repressed in ß cells, suggesting that tumoral transition involves derepression of polycomb-targeted domains. Our work provides a compendium of aberrant cis-regulatory elements affecting the function and fate of ß cells in their progression to insulinomas and a framework to identify coding and noncoding driver mutations.

Endoscopic ultrasonography-based intratumoral and peritumoral machine learning radiomics analyses for distinguishing insulinomas from non-functional pancreatic neuroendocrine tumors.

Objectives: To develop and validate radiomics models utilizing endoscopic ultrasonography (EUS) images to distinguish insulinomas from non-functional pancreatic neuroendocrine tumors (NF-PNETs). Methods: A total of 106 patients, comprising 61 with insulinomas and 45 with NF-PNETs, were included in this study. The patients were randomly assigned to either the training or test cohort. Radiomics features were extracted from both the intratumoral and peritumoral regions, respectively. Six machine learning algorithms were utilized to train intratumoral prediction models, using only the nonzero coefficient features. The researchers identified the most effective intratumoral radiomics model and subsequently employed it to develop peritumoral and combined radiomics models. Finally, a predictive nomogram for insulinomas was constructed and assessed. Results: A total of 107 radiomics features were extracted based on EUS, and only features with nonzero coefficients were retained. Among the six intratumoral radiomics models, the light gradient boosting machine (LightGBM) model demonstrated superior performance. Furthermore, a peritumoral radiomics model was established and evaluated. The combined model, integrating both the intratumoral and peritumoral radiomics features, exhibited a comparable performance in the training cohort (AUC=0.876) and achieved the highest accuracy in predicting outcomes in the test cohorts (AUC=0.835). The Delong test, calibration curves, and decision curve analysis (DCA) were employed to validate these findings. Insulinomas exhibited a significantly smaller diameter compared to NF-PNETs. Finally, the nomogram, incorporating diameter and radiomics signature, was constructed and assessed, which owned superior performance in both the training (AUC=0.929) and test (AUC=0.913) cohorts. Conclusion: A novel and impactful radiomics model and nomogram were developed and validated for the accurate differentiation of NF-PNETs and insulinomas utilizing EUS images.

[18F]FB(ePEG12)12-exendin-4 noninvasive imaging of insulinoma negative for insulin immunostaining on specimen from endoscopic ultrasonography-guided fine needle aspiration: a case report with review of literature.

Insulinomas are the most common functional pancreatic neuroendocrine neoplasm; when treatment is delayed, they induce hyperinsulinemic hypoglycemia, which is life-threatening. As surgical resection is the only curative treatment for insulinoma, preoperative localization is crucial; however, localization based on conventional imaging modalities such as computed tomography (CT) and magnetic resonance imaging is often inconclusive. Somatostatin receptor-targeted imaging is another option for detecting pancreatic neuroendocrine neoplasms but has low sensitivity and is not specific for insulinoma. The clinical application of other localizing approaches such as selective arterial calcium stimulation and endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA) is limited by their being invasive and/or technically complex. Moreover, an EUS-FNA specimen of an insulinoma may be negative on insulin immunostaining. Thus, a noninvasive and clinically practical insulinoma-specific diagnostic tool to discriminate insulinomas with high accuracy is anticipated. Glucagon-like peptide-1 receptor (GLP-1R)-targeted imaging has emerged in the effort to fulfill this need. We recently developed the novel fluorine-18-labeled exendin-4-based probe conjugated with polyethylene glycol, [18F]FB(ePEG12)12-exendin-4 (18F-exendin-4) for positron emission tomography (PET) imaging and reported its clinical benefit in a case of insulinoma in the pancreatic tail. We report here a case of insulinoma in the pancreatic head in which an EUS-FNA specimen was negative on insulin immunostaining while precise preoperative localization and conclusive evidence for curative enucleation was provided by 18F-exendin-4 PET/CT (Japan Registry of Clinical Trials; jRCTs051200156).

Differences in intratumor innate lymphoid cell composition between orthotopic and spontaneous pancreatic mouse models.

Pancreatic cancer remains an unmet medical need. Late diagnosis and the lack of efficient treatment significantly impact the prognosis of patients suffering from pancreatic cancer. Improving patient outcomes requires a deeper comprehension of the tumor ecosystem. To achieve this, a thorough exploration of the tumor microenvironment using pre-clinical models that accurately replicate human disease is imperative, particularly in understanding the dynamics of immune cell subsets. Surprisingly, the impact of model variations on the composition of the tumor microenvironment has been largely neglected. In this study, we introduce an orthotopic model of pancreatic ductal adenocarcinoma and a spontaneous model of insulinoma. Our findings reveal striking differences in the innate lymphoid cell infiltrate, highlighting the importance of considering model-specific influences when investigating the tumor microenvironment.

SAP deletion promotes malignant insulinoma progression by inducing CXCL12 secretion from CAFs via the CXCR4/p38/ERK signalling pathway.

Malignant insulinoma is an extremely rare type of functioning pancreatic neuroendocrine tumour with a high degree of malignancy and a high incidence of metastasis. However, it is still unclear how malignant insulinomas develop and metastasize. Serum amyloid P component (SAP), a member of the pentraxin protein family, is an acute-phase protein secreted by liver cells. The role of SAP in insulinoma and the related mechanism are still unknown. To determine the effect of SAP on insulinoma, we crossed Rip1-Tag2 mice, which spontaneously develop insulinoma, and SAP knockout (KO) mice to generate Rip1-Tag2;SAP-/- mice. We found that SAP deletion significantly promoted the growth, invasion and metastasis of malignant insulinoma through C-X-C motif chemokine ligand 12 (CXCL12) secreted by cancer-associated fibroblasts (CAFs). Further study showed that SAP deletion promoted CXCL12 secretion by CAFs through the CXCR4/p38/ERK signalling pathway. These findings reveal a novel role and mechanism of SAP in malignant insulinoma and provide direct evidence that SAP may be a therapeutic agent for this disease.

Genetic disorders and insulinoma/glucagonoma.

Insulinoma and glucagonoma are two rare functioning neoplasms of the neuroendocrine cells of the pancreas, respectively, characterized by an uncontrolled over-secretion of insulin or glucagon, responsible for the development of the hypoglycemic syndrome and the glucagonoma syndrome. They prevalently arise as sporadic tumors; only about 10% of cases develop in the context of rare inherited tumor syndromes, such as multiple endocrine neoplasia type 1 (MEN1), neurofibromatosis type 1 (NF1), and tuberous sclerosis complex (TSC), being the result of an autosomal-dominant germline heterozygous loss-of-function mutation in a tumor-suppressor gene. Here, we reviewed the main epidemiological and clinical aspects of insulinoma and glucagonoma in the context of genetic syndromes.

Genotype-histotype-phenotype correlations in hyperinsulinemic hypoglycemia.

Hyperinsulinemic hypoglycemia (HH) of pancreatic origin includes congenital hyperinsulinism (CHI), insulinoma, insulinomatosis, and adult-onset non-insulinoma persistent hyperinsulinemic hypoglycemia syndrome (NI-PHHS). In this review, we describe the genotype-histotype-phenotype correlations in HH and their therapeutic implications. CHI can occur from birth or later on in life. Histologically, diffuse CHI shows diffuse beta cell hypertrophy with a few giant nuclei per islet of Langerhans, most frequently caused by loss-of-function mutations in ABCC8 or KCNJ11. Focal CHI is histologically characterized by focal adenomatous hyperplasia consisting of confluent hyperplastic islets, caused by a paternal ABCC8/KCNJ11 mutation combined with paternal uniparental disomy of 11p15. CHI in Beckwith-Wiedemann syndrome is caused by mosaic changes in the imprinting region 11p15.4-11p15.5, leading to segmental or diffuse overgrowth of endocrine tissue in the pancreas. Morphological mosaicism of pancreatic islets is characterized by occurence of hyperplastic (type 1) islets in one or a few lobules and small (type 2) islets in the entire pancreas. Other rare genetic causes of CHI show less characteristic or unspecific histology. HH with a predominant adult onset includes insulinomas, which are pancreatic insulin-producing endocrine neoplasms, in some cases with metastatic potential. Insulinomas occur sporadically or as part of multiple endocrine neoplasia type 1 due to MEN1 mutations. MAFA mutations may histologically lead to insulinomatosis with insulin-producing neuroendocrine microadenomas or neuroendocrine neoplasms. NI-PHHS is mainly seen in adults and shows slight histological changes in some patients, which have been defined as major and minor criteria. The genetic cause is unknown in most cases. The diagnosis of HH, as defined by genetic, histological, and phenotypic features, has important implications for patient management and outcome.

Exploring dual effects of dinutuximab beta on cell death and proliferation of insulinoma.

Insulinoma INS-1 cells are pancreatic beta cell tumors. Dinutuximab beta (DB) is a monoclonal antibody used in the treatment of neuroblastoma. The aim of this study is to investigate the effects of DB on pancreatic beta cell tumors at the molecular level. DB (Qarziba®) was available from EUSA Pharma. Streptozotocin (STZ) was used induce to cell cytotoxicity. DB was applied to the cells before or after the STZ application. KCND3, KCNN4, KCNK1, and PTHrP gene expression levels were analyzed by q-RT-PCR, and protein levels were analyzed by Western blotting. Analysis of glucose-stimulated insulin secretion was performed. Ca+2 and CA19-9 levels were determined by the ELISA kit. PERK, CHOP, HSP90, p-c-Jun, p-Atf2, and p-Elk1 protein levels were analyzed by simple WES. Decreased KCND3, KCNK1, and PTHrP protein levels and increased KCND3, KCNN4, KCNK1, and PTHrP gene expression levels were observed with DB applied after STZ application. Cell dysfunction was detected with DB applied before and after STZ application. Ca19-9 and Ca+2 levels were increased with DB applied after STZ application. PERK, CHOP, and p-Elk1 levels decreased, while HSP90 levels increased with DB applied after STZ application. CHOP, p-Akt-2, and p-c-Jun levels increased in the DB group. As a result, INS-1 cells go to cell death via the ERK signaling pathway without ER stress and release insulin with the decrease of K+ channels and an increase in Ca+2 levels with DB applied after STZ application. Moreover, the cells proliferate via JNK signaling with DB application. DB holds promise for the treatment of insulinoma. The study should be supported by in vivo studies.

Clinical Case Report of Non-Diabetic Hypoglycemia Due to a Combination of Germline Mutations in the MEN1 and ABCC8 Genes.

INTRODUCTION: Non-diabetic hypoglycemia (NDH) is a collective term including the multiple causes of hypoglycemic syndrome not due to diabetes mellitus. NDH may result from insulinoma, IGF-2-omas, hypocorticism, Hirata's disease, genital disorders of glucose metabolism, etc. One of the most common causes of NDH faced by an endocrinologist is insulinoma, which in turn can be part of the hereditary syndrome of multiple endocrine neoplasia type 1 (MEN1). Congenital disorders of glucose metabolism in adult patients, on the contrary, are diagnosed extremely rarely, since they usually manifest in childhood. This article presents a unique clinical case of a patient with NDH and genetically verified MEN1 in combination with congenital hyperinsulinism due to an ABCC8 gene mutation. CASE REPORT: A 43-year-old patient with hypoglycemic symptoms from childhood is presented, in whom multiple pancreatic tumors and fluctuations in glycemia from 38.7 mg/dL to 329.7 mg/dL (2.15 to 18.3 mmol/L) were detected in adulthood, but a mild course of hypoglycemic syndrome was noted. Numerous examinations that were performed to establish an accurate diagnosis are described, signs that served as a reason for expanding the complex of studies are indicated, possible pathogenetic mechanisms of the mild course of hypoglycemic syndrome and hyperglycemic conditions are discussed. CONCLUSION: This case report is original and highlights that we must always remain intolerant of the inexplicable. Conducting an extended gene study can help perform a correct diagnosis in complex cases.

Is hyperinsulinemia a possible clinical explanation underlying the myth of Erysichthon?

BACKGROUND: An insulinoma is an endocrine tumor of the pancreas, originating from the beta cells, and has a prevalence of 4 cases per 1 million patients. Insulinomas often follow a "90% rule": 90% are benign [1, 2], 90% originate in the pancreas, 90% are approximately 2 cm wide, and 90% are isolated. Individuals with an insulinoma may have episodic bouts of hyperinsulinemic hypoglycemia. Typically, an insulinoma is indicated by hypoglycemic symptoms which are a result of catecholamine reaction and neuroglycopenia. There is increased secretion of insulin in patients with an insulinoma despite having lower glucose levels. PURPOSE: This paper examines the myth of Erysichthon and speculates whether the symptoms experienced by him are possibly related to those found in patients with an hyperinsulinoma. METHODS: The myth of Erysichthon was taken from various sources (i.e. Hesiod, Callimachus, Ovid) and examined. Symptoms of Erysichthon were then examined. RESULTS: The myth of Erysichthon depicts various sympathoadrenal and neuroglycopenic symptoms including anxiety and abnormal behaviour which can be found in insulinomas. Insulinomas may often present a diagnostic challenge due to their deceptive nature and overlapping symptoms with other disorders such as neurologic disease. Insulinomas inducing weight loss resemble Calamachus's account of Erysichthon whose body is finally emaciated, even though having polyphagia. CONCLUSION: The myth of Erysichthon provides an interesting range of clinical symptoms which I have argued relate to symptoms found in patients with an insulinoma. Although, insulinomas were unknown in ancient medical lore, this paper has speculated that based on Erysichthon's symptoms, the possibility of an insulinoma cannot be ruled out.

Safety and efficacy of endoscopic ultrasound-guided radiofrequency ablation for pancreatic insulinoma: A single-center experience.

BACKGROUND/OBJECTIVES: Insulinomas are rare, functioning pancreatic neuroendocrine neoplasms (pNEN), whose gold standard therapy is surgical resection. Endoscopic ultrasound-guided radiofrequency ablation (EUS-RFA) is a recent technique that has emerged as a minimally invasive therapeutic option for patients with pancreatic lesions not eligible for surgery. In this study, we aimed to describe a series of patients with unresectable pancreatic insulinoma treated with EUS-RFA. METHODS: This is a single-center, retrospective study including all consecutive patients with functioning pancreatic insulinoma undergoing EUS-RFA for surgical unfitness or surgery refusal, between March 2017 and September 2021. Technical success (i.e., complete mass ablation), adverse event rate and severity, clinical and radiologic outcomes (i.e., symptom remission with a normal concentration of blood glucose, and the presence of intralesional necrosis), and post-procedural follow-up were assessed. RESULTS: A total of 10 patients (mean age: 67.1 ± 10.1years; F:M 7:3) were included. The mean size of insulinoma was 11.9 ± 3.3 mm. Technical success and clinical remission were achieved in 100% of patients. Only one (10%) patient was successfully treated with two RFA sessions. Two procedure-related early adverse events occurred, including two (20%) cases of mild abdominal pain. No major complications were observed. The complete radiologic response within 3 months after EUS-RFA was observed in all patients (100%). After a median follow-up of 19.5 (range12-59) months, symptom remission and persistent euglycemia were assessed in all the patients. CONCLUSIONS: Data from this case series suggest that EUS-RFA is a feasible and safe therapeutic approach for pancreatic insulinomas in patients unwilling or unable to undergo surgery with medium-term efficacy.

Case Report: Giant insulinoma, a very rare tumor causing hypoglycemia.

Insulinomas, with an incidence of 4 cases per million individuals per year, remain amongst the most frequent functional neuroendocrine tumors. The usual diameter of insulinomas usually remains under 3 cm of major axis. However, 44 exceptional cases of "giant insulinomas", have been reported worldwide, generally exceeding 9 cm in major axis. In this article, we report the case of a 38-year-old woman whom suffered from chronic hypoglycemia despite treatment with diazoxide. Abdominal CT-scan revealed a 88 x 73 mm mass located at the tail of the pancreas. Following surgical excision, histopathological analysis confirmed G1 neuroendocrine tumor, with focal cytoplasmic expression of insulin in tumor cells. After a 16-month follow-up period, the patient didn't address any specific complaint, and no disease recurrence and/or metastasis were observed. A 68Ga-DOTATATE-PET scan was performed 6 months after surgery, which came back normal. Genetic evaluation has not been performed in our patient. The physiopathology of giant insulinomas remain unexplained, however with possible relationship with type 1 multiple endocrine neoplasia, sporadic somatic YY1 mutations and possible transformation of bulky non-functional pancreatic neuroendocrine tumors to a functional phenotype, with slow insulin secretion. While giant insulinomas remain rare in the literature, multicentric genetic analysis of tumor samples might reveal unique features of this rare subtype of neuroendocrine pancreatic tumors. Insulinomas of large size tend to have greater malignancy and higher rates of invasiveness. Careful follow-up, especially for liver and lymph node metastases, must be performed using functional imaging techniques to avoid disease relapse.

Insulinoma in childhood: a retrospective review of 22 patients from one referral centre.

Background: Insulinomas are very rare in childhood with sparse knowledge on the clinical aspects and the presence of Multiple Endocrine Neoplasia type 1 (MEN1). Methods: We conducted a retrospective review of patients diagnosed with insulinoma between 1995 and 2021, presenting to one referral centre in Russia. Clinical, biochemical, genetic, imaging and histological data were collected. In addition, follow-up and family data were obtained. Results: A total of twenty-two children aged 5 to 16 years were identified. The median (range) gap between the first hypoglycaemia symptoms and diagnosis was 10 (1-46) months. Twelve children (55%) were misdiagnosed to have epilepsy and were treated with anticonvulsants before hypoglycemia was revealed. Contrast enhanced MRI and/or CT were accurate to localize the lesion in 82% (n=18). Five patients (23%) had multiple pancreatic lesions. All children underwent surgical treatment. The median (range) diameter of removed tumors was 1.5 (0.3-6) cm. Histopathological studies confirmed the presence of insulinoma in all cases. Immunohistochemical studies revealed G2 differentiation grade in 10 out of 17 cases. Two patients were diagnosed with metastatic insulinoma. One of them had metastases at the time of insulinoma diagnosis, while the other was diagnosed with liver metastases eight years after the surgery. Eight children (36%) were found to carry MEN1 mutations, inherited n=5, de novo n=1, no data, n=2. Children with MEN1 had significantly higher number of pancreatic tumors compared to sporadic cases. All of them developed additional MEN1 symptoms during the following 2-13 years. In the five patients with inherited MEN1, seven family members had hitherto undiscovered MEN1 manifestations. Conclusions: In this large cohort of children with rare pediatric insulinomas, MEN1 syndrome and G2 tumors were frequent, as well as hitherto undiscovered MEN1 manifestations in family members. Our data emphasize the need of genetic testing in all children with insulinoma and their relatives, even in the absence of any other features, as well as the importance of a prolonged follow-up observation.

Multiple endocrine neoplasia in a sheep: insulinoma, adrenocortical carcinoma with myxoid differentiation, and thyroid C-cell carcinoma.

An ~10-y-old male sheep had anorexia and progressive weight loss for ~1 mo. The sheep was emaciated, and 20 d later, became recumbent and lethargic, and was hypoglycemic (0.33 mmol/L; RI: 2.6-4.4 mmol/L). The sheep was euthanized because of poor prognosis, and submitted for autopsy. We found no gross lesions in the pancreas; however, histologically, focal proliferations of round-to-polygonal cells were separated by connective tissue into small nests. These proliferating cells, which had abundant eosinophilic-to-amphophilic cytoplasm and hyperchromatic nuclei, were immunopositive for insulin and negative for glucagon and somatostatin; the lesion was diagnosed as an insulinoma. Insulinoma has not been reported previously in sheep, to our knowledge. In addition, autopsy and histologic examination revealed the presence of an adrenocortical carcinoma with myxoid differentiation and a thyroid C-cell carcinoma. Our case indicates that multiple endocrine neoplasms can occur in sheep, as in other animal species.

Pancreatic insulinoma misdiagnosed as atrial fibrillation: A case report from Iraq.

RATIONALE: Pancreatic insulinomas are the most frequent pancreatic endocrine neoplasms. They are insulin-secreting pancreatic tumors that induce extreme, recurrent, and near-fatal hypoglycemia. Insulinomas affect 1 to 4 individuals in a million of the general population and account for about 1% to 2% of all pancreatic tumors. PATIENT CONCERNS: Recurrent episodes of sweating, tremor, weakness, confusion, palpitation, blurred vision, and fainting for 2 months and was misdiagnosed as having atrial fibrillation. DIAGNOSIS: He was misdiagnosed as having atrial fibrillation to highlight the importance of atrial fibrillation as unusual mimicker of insulinoma and to encourage clinicians about the importance of early and appropriate management in such cases. INTERVENTIONS: Endoscopic ultrasound for the pancreatic parenchyma was done, and it showed a hypoechoic homogenous mass located at the pancreatic head measuring 12 mm × 15 mm with no local vascular involvement, blue in elastography, hypervascular with Doppler study, and a normal pancreatic duct diameter. OUTCOMES: His condition was stable, and he was discharged home 2 days later. CONCLUSION: The diagnosis of insulinoma is usually difficult and late due to the extremely low incidence of the disease and the similarity of its clinical presentation to numerous other conditions, the most reported is epilepsy.