Persistent hyperinsulinemic hypoglycemia in 15 adults with diffuse nesidioblastosis: diagnostic criteria, incidence, and characterization of beta-cell changes

Adult-onset diffuse nesidioblastosis causing hypoglycemia

We report the case of a 32-year-old male with adult-onset diffuse nesidioblastosis causing hypoglycemia. Under the tentative diagnosis of insulinoma, localization procedures were carried out but no tumor was found. The presence of an insulinoma in the tail of the pancreas was suggested by selective intra-arterial calcium stimulation with hepatic venous sampling (ASVS). A distal pancreatectomy was performed under the assumed diagnosis of insulinoma in the tail based upon the ASVS. Diffuse nesidioblastosis was diagnosed by histopathological evaluation. During the post-operative course, the patient's glucose and insulin levels were well controlled and uneventful without any medications or insulin for 7 months.

Hypoglycemia due to an adult-onset nesidioblastosis, a diagnostic and management dilemma

We describe a case of a 40 year old patient with recurrent severe fasting and postprandial symptomatic hypoglycemia that occurred 6 years after gastric bypass surgery. The hypoglycemia was associated with increased insulin and C peptide but all diagnostic modalities for localizing an insulinoma were negative. Medical management failed to control symptoms and the patient underwent subtotal pancreatectomy. Surgical tissue examination confirmed the diagnosis of noninsulinoma pancreatogenous hypoglycaemia syndrome (NIPHS) or nesidioblastosis. Initially after surgery the patient had full remission but after 6 months hypoglycemia recurred. However, this time it was well-controlled with octreotide treatment.

A rare case of noninsulinoma pancreatogenous hypoglycemia syndrome

As the obesity pandemic continues to worsen and medical interventions remain only moderately effective, bariatric surgery remains an important option for patients. In certain instances, patients who have undergone the procedure experience postprandial symptoms of neuroglycopenia caused by noninsulinoma pancreatogenous hypoglycemia syndrome (NIPHS). NIPHS is a recently described syndrome and is also very rare, and therapeutic approaches are still under debate. We report the case of a 51-year-old female who underwent Roux-en-Y gastric bypass and presented with episodic postprandial hypoglycemia 2 years after surgery. An insulinoma was absent from all abdominal imaging. Fasting C-peptide, insulin, and glucose were normal. Due to the possibility of NIPHS, clinical treatment was commenced with acarbose, leading to a significant reduction of hypoglycemic episodes. NIPHS occurs in approximately 0.5% to 7% of patients with hyperinsulinemic hypoglycemia. Sporadic hypoglycemia postgastric bypass is an important entity that should be understood by all surgeons and internists who are involved in postgastric bypass care.

Diffuse nesidioblastosis with hypoglycemia mimicking an insulinoma: a case report

Introduction

We describe a case of diffuse nesidioblastosis in an adult patient who presented with exclusively fasting symptoms and a focal pancreatic ¹¹¹In-pentetreotide uptake mimicking an insulinoma.

Case presentation

A 23-year-old Caucasian man had severe daily fasting hypoglycemia with glucose levels below 2mmol/L. Besides rare neuroglycopenic symptoms (confusion, sleepiness), he was largely asymptomatic. His investigations revealed low venous plasma glucose levels, high insulin and C-peptide levels and a 72-hour fast test that were all highly suggestive for an insulinoma. Abdominal computed tomography and magnetic resonance imaging did not reveal any lesions. The sole imagery that was compatible with an insulinoma was a ¹¹¹In-somatostatin receptor scintigraphy that showed a faint but definite focal tracer between the head and the body of the pancreas. However, this lesion could not be confirmed by endoscopic ultrasonography of the pancreas. Following duodenopancreatectomy, the histological findings were consistent with diffuse nesidioblastosis. Postoperatively, the patient continued to present with fasting hypoglycemia and was successfully treated with diazoxide.

Conclusion

In the absence of gastrointestinal surgery, nesidioblastosis is very rare in adults. In addition, nesidioblastosis is usually characterized by post-prandial hypoglycemia, whereas this patient presented with fasting hypoglycemia. This case also illustrates the risk for a false positive result of ¹¹¹In-pentetreotide scintigraphy in the case of nesidioblastosis. Selective arterial calcium stimulation and venous sampling is the most reliable procedure for the positive diagnosis of insulinoma or nesidioblastosis and should be used to confirm any suspicion based on imaging modalities.

Hyperinsulinism presenting in childhood and treatment by conservative pancreatectomy

OBJECTIVE

To describe the uncommon presentation of hyperinsulinism in an 8-year-old boy.

METHODS

We describe the patient's clinical findings, results from biochemical and imaging studies, surgical approach, and outcome. The discussion encompasses a review of literature that provided the basis for the diagnostic and surgical approach applied to this patient's case.

RESULTS

An obese 8.5-year-old boy initially presented with hypoglycemic seizures after initiation of dietary changes to treat obesity. Biochemical analysis indicated hyperinsulinism. Endoscopic ultrasonography showed no pancreatic lesions suggestive of insulinoma. Genetic studies identified no known mutations in the ABCC8, KCNJ11, GCK, or GLUD1 genes. Selective arterial calcium stimulation and hepatic venous sampling did not document a focal source for hyperinsulinism in the pancreas, and positron emission tomography with 18-fluoro-L-3,4-dihydroxyphenylalanine showed diffusely increased uptake in the pancreas. The patient ultimately required partial pancreatectomy because of continued hypoglycemia while taking diazoxide and octreotide. Intraoperative glucose monitoring directed the extent of surgical resection. A 45% pancreatectomy was performed, which resolved the hypoglycemia but led to impaired glucose tolerance after surgery.

CONCLUSION

The unusual presentation of hyperinsulinism in childhood required a personalized approach to diagnosis and surgical management using intraoperative glucose monitoring that resulted in a conservative pancreatectomy.

Long-term in vitro culture of hamster pancreatic β-cells and induction of adenocarcinoma by treatment with N-nitrosobis(2-oxopropyl)amine

OBJECTIVES

Earlier studies indicated that hamster pancreatic ductal adenocarcinoma not only derives from ductal/ductular structures but also from cells within the islet. So far unidentified cells within the islet are responsive to the carcinogenic effect of N-nitrosobis (2-oxopropyl) amine (BOP) forming poorly differentiated ductal adenocarcinoma. However, studies indicated a major role of β-cells during carcinogenesis. To find out, if β-cells are the primary target cells of BOP and if they are capable to form ductal adenocarcinoma after malignant transformation, we established a long-term culture of undifferentiated cells deriving from isolated β-cells and treated them with BOP.

METHODS

Langerhans' islets from pancreata of Syrian golden hamsters were isolated and dispersed into single cells by dispase digestion. Cells were labeled with a highly specific β-cell surface antibody (K14D10) and these K14D10+ cells were extracted from the suspension by paramagnetic Dynabeads. Cells were cultured in vitro and treated with BOP. Untreated cells served as control.

RESULTS

K14D10+ cells formed a monolayer and produced insulin over a period of 28 days in culture. However, with time in culture they became undifferentiated with a higher proliferation rate and after about 60 days in culture BOP treated cells showed anchorage independent growth. These cells autotransplanted s.c. formed a well-differentiated ductal adenocarcinoma.

CONCLUSIONS

Pancreatic β-cells are the primary target of BOP without necessarily being embedded in the compound of the Langerhans' islet. With time in culture, they give rise to undifferentiated cells and after malignant transformation they are able to form ductal adenocarcinoma.

Prolonged successful therapy for hyperinsulinaemic hypoglycaemia after gastric bypass: the pathophysiological role of GLP1 and its response to a somatostatin analogue

BACKGROUND

Spontaneous hyperinsulinaemic hypoglycaemia following gastric bypass surgery (GBS) is increasingly recognised. However, its pathophysiology remains unclear. Some patients require pancreatectomy. Medical therapy with calcium channel blockers, acarbose and diazoxide has been reported to be beneficial but has variable adherence and response.

METHOD

We demonstrate the role of GLP1, counter-regulatory hormones and the subsequent response of GLP1 to somatostatin analogue therapy in a 42-year-old woman with persistent neuroglycopaenia 6 years after GBS. Plasma GLP1, insulin and glucose were measured for 5  h on three settings: i) a 75  g oral glucose tolerance test (OGTT); ii) a standard liquid test meal (LTM); and iii) an OGTT 30  min after a s.c. injection of 100  μg octreotide.

RESULTS

In comparison with obese non-diabetic controls, the patient had an elevated fasting and a markedly enhanced GLP1 response during the OGTT, followed by an exaggerated insulin response and a subsequent low glucose level. The GLP1 response to a LTM was similar but greater. Octreotide given prior to the OGTT attenuated both the GLP1 and insulin responses and abolished hypoglycaemia. Octreotide therapy significantly improved the patient's neuroglycopaenic symptoms. The hormone profile was reassessed after 6 months following the LTM preceded by octreotide injection. Peak GLP1 and insulin responses were less pronounced than pretreatment responses and without hypoglycaemia. The patient was treated with lanreotide and had remained symptom-free and euglycaemic for 4 years.

CONCLUSION

An exaggerated incretin response following altered gastrointestinal anatomy was the likely cause of hypoglycaemia in our GBS patient. Somatostatin successfully suppressed this response acutely and in the long term, thereby avoiding pancreatectomy and its sequelae.

[Neuroendocrine neoplasms of the gastrointestinal tract. Classification, clinical presentation and diagnosis]

Neuroendocrine neoplasms of the digestive system represent a rare and heterogeneous group of malignancies with various clinical presentations and prognoses. The WHO classification for the year 2000 was updated in 2010 to take the histopathology and tumor biology of these tumors into account. Together with proliferation-based grading and the recently established staging system using the ENETS TNM classification, it forms the basis for the further diagnostic and therapeutic approach. Clinical presentation depends mainly on the primary site of the tumor and its functionality. Characteristic symptoms are seen only rarely, this being the reason these tumors are usually detected at an advanced stage. Approximately 30% of GEP-NEN are hormonally active and can cause a specific clinical syndrome. In addition to these specific hormones, chromogranin A is considered the most accurate general marker for the biochemical follow-up of these patients. In addition to commonly used radiological and endoscopic imaging modalities, somatostatin receptor-based functional imaging using either octreotide scintigraphy or novel PET-based techniques with specific isotopes such as Ga68-DOTA-octreotate play a crucial role in the detection of the primary tumor as well as in the evaluation of tumor extent and the selection of patients for receptor-based radionuclide therapy.

Advances in the etiology and management of hyperinsulinemic hypoglycemia after Roux-en-Y gastric bypass

INTRODUCTION

Hyperinsulinemic hypoglycemia with severe neuroglycopenia has been identified as a late complication of Roux-en-Y gastric bypass (RYGB) in a small number of patients.

DISCUSSION

The rapid resolution of type 2 diabetes mellitus after RYGB is probably related to increased secretion of the incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), and patients with post-RYGB hypoglycemia demonstrate prolonged elevations of GIP and GLP-1 compared to non-hypoglycemic post-RYGB patients. Nesidioblastosis has been identified in some patients with post-RYGB hypoglycemia and is likely due to the trophic effects of GIP and GLP-1 on pancreatic islets.

CONCLUSIONS

Treatment of hypoglycemia after RYGB should begin with strict dietary (low carbohydrate) alteration and may require a trial of diazoxide, octreotide, or calcium-channel antagonists, among other drugs. Surgical therapy should include consideration of a restrictive form of bariatric procedure, with or without reconstitution of gastrointestinal continuity. Partial or total pancreatic resection should be avoided.

Pathologic pancreatic endocrine cell hyperplasia

Pathologic hyperplasia of various pancreatic endocrine cells is rare but has been long known. β cell hyperplasia contributes to persistent hyperinsulinemic hypoglycemia of infancy, which is commonly caused by mutations in the islet ATP-sensitive potassium channel, and to non-insulinoma pancreatogenous hypoglycemia in adults, which may or may not be associated with bariatric surgery. α cell hyperplasia may cause glucagonoma syndrome or induce pancreatic neuroendocrine tumors. An inactivating mutation of the glucagon receptor causes α cell hyperplasia and asymptomatic hyperglucagonemia. Pancreatic polypeptide cell hyperplasia has been described without a clearly-characterized clinical syndrome and hyperplasia of other endocrine cells inside the pancreas has not been reported to our knowledge. Based on morphological evidence, the main pathogenetic mechanism for pancreatic endocrine cell hyperplasia is increased endocrine cell neogenesis from exocrine ductal epithelium. Pancreatic endocrine cell hyperplasia should be considered in the diagnosis and management of hypoglycemia, elevated islet hormone levels, and pancreatic neuroendocrine tumors. Further studies of pathologic pancreatic endocrine cell hyperplasia will likely yield insights into the pathogenesis and treatment of diabetes and pancreatic neuroendocrine tumors.

Hyperinsulinemic hypoglycemia after Roux-en-Y gastric bypass: unraveling the role of gut hormonal and pancreatic endocrine dysfunction

BACKGROUND

Profound hypoglycemia occurs rarely as a late complication after Roux-en-Y gastric bypass (RYGB). We investigated the role of glucagon-like-peptide-1 (GLP-1) in four subjects who developed recurrent neuro-glycopenia 2 to 3 y after RYGB.

METHODS

A standardized test meal (STM) was administered to all four subjects. A 2 h hyperglycemic clamp with GLP-1 infusion during the second hour was performed in one subject, before, during a 4 wk trial of octreotide (Oc), and after 85% distal pancreatectomy. After cessation of both glucose and GLP-1 infusion at the end of the 2 h clamp, blood glucose levels were monitored for 30 min. Responses were compared with a control group (five subjects 12 mo status post-RYGB without hypoglycemic symptoms).

RESULTS

During STM, both GLP-1 and insulin levels were elevated 3- to 4-fold in all subjects, and plasma glucose-dependent insulinotropic peptide (GIP) levels were elevated 2-fold. Insulin responses to hyperglycemia ± GLP-1 infusion in one subject were comparable to controls, but after cessation of glucose infusion, glucose levels fell to 40 mg/dL. During Oc, the GLP-1 and insulin responses to STM were reduced (>50%). During the clamp, insulin response to hyperglycemia alone was reduced, but remained unchanged during GLP-1. Glucagon levels during hyperglycemia alone were suppressed and further suppressed after the addition of GLP-1. With the substantial drop in glucose during the 30 min follow-up, glucagon levels failed to rise. Due to persistent symptoms, one subject underwent 85% distal pancreatectomy; postoperatively, the subject remained asymptomatic (blood glucose: 119-220 mg/dL), but a repeat STM showed persistence of elevated levels of GLP-1. Histologically enlarged islets, and β-cell clusters scattered throughout the acinar parenchyma were seen, as well as β-cells present within pancreatic duct epithelium. An increase in pancreatic and duodenal homeobox-1 protein (PDX-1) expression was observed in the subject compared with control pancreatic tissue.

CONCLUSIONS

A persistent exaggerated hypersecretion of GLP-1, which has been shown to be insulinotropic, insulinomimetic, and glucagonostatic, is the likely cause of post-RYGB hypoglycemia. The hypertrophy and ectopic location of β-cells is likely due to overexpression of the islet cell transcription factor, PDX-1, caused by prolonged hypersecretion of GLP-1.

Successful treatment of persistent hyperinsulinemic hypoglycemia with nifedipine in an adult patient

OBJECTIVE

To describe the successful treatment of severe noninsulinoma hyperinsulinemic hypoglycemia with use of a calcium channel blocking agent in an adult patient who had previously undergone a gastric bypass surgical procedure.

METHODS

A 65-year-old woman who had undergone a gastric bypass surgical procedure 26 years earlier was hospitalized because of severe postprandial hypoglycemia. During and after hospitalization, the patient underwent assessment with conventional measurements of glucose, insulin, proinsulin, and C-peptide; toxicologic studies; magnetic resonance imaging studies of the pancreas; and determination of hepatic vein insulin concentrations after selective splanchnic artery calcium infusion.

RESULTS

Metabolic variables were consistent with the diagnosis of hyperinsulinemic hypoglycemia. Magnetic resonance imaging revealed the presence of a side branch intraductal papillary mucinous tumor that had been stable for more than 1 year. The results of the calcium-stimulated insulin release study were consistent with nonlocalized hypersecretion of insulin. A trial of frequent small feedings failed to prevent hypoglycemia. On the basis of reports of successful treatment of childhood nesidioblastosis, the patient was then prescribed nifedipine, 30 mg daily. She has subsequently remained free of symptomatic hypoglycemia for 20 months.

CONCLUSION

A calcium channel blocking agent may be efficacious and a potential alternative to partial pancreatectomy in cases of noninsulinoma hyperinsulinemic hypoglycemia in adults.

Case report: focal nesidioblastosis ("nesidioblastoma") in an adult

Adult nesidioblastosis is an uncommon cause of hyperinsulinemic hypoglycemia characterized by diffuse islet hyperplasia with beta-cell hypertrophy and atypia. The cause of nesidioblastosis in adults is unclear but may be different from nesidioblastosis in infants. In contrast to infants, a focal form of adult nesidioblastosis (ie, "nesidioblastoma") has not been documented, although proposed. We report a 44-year-old man with symptomatic hypoglycemia and localized nesidioblastosis treated with surgical enucleation resulting in normalization of blood glucose. Postoperative euglycemia has persisted in this patient to date (4 months at the time of manuscript submission).

LKB1 regulates pancreatic beta cell size, polarity, and function

Pancreatic beta cells, organized in the islets of Langerhans, sense glucose and secrete appropriate amounts of insulin. We have studied the roles of LKB1, a conserved kinase implicated in the control of cell polarity and energy metabolism, in adult beta cells. LKB1-deficient beta cells show a dramatic increase in insulin secretion in vivo. Histologically, LKB1-deficient beta cells have striking alterations in the localization of the nucleus and cilia relative to blood vessels, suggesting a shift from hepatocyte-like to columnar polarity. Additionally, LKB1 deficiency causes a 65% increase in beta cell volume. We show that distinct targets of LKB1 mediate these effects. LKB1 controls beta cell size, but not polarity, via the mTOR pathway. Conversely, the precise position of the beta cell nucleus, but not cell size, is controlled by the LKB1 target Par1b. Insulin secretion and content are restricted by LKB1, at least in part, via AMPK. These results expose a molecular mechanism, orchestrated by LKB1, for the coordinated maintenance of beta cell size, form, and function.

Neuroendocrine tumors of the pancreas

This literature review briefly summarizes the epidemiology, pathophysiology, clinical management, and outcomes of patients with pancreatic neuroendocrine tumors (PNETs) and highlights recent advances in PNET research. PNETs are rare neoplasms, compared with carcinomas arising from pancreatic exocrine tissue. They, like other neuroendocrine tumor types, display variable malignant potential, hormone-related syndromes (functionality), localization, and genetic background. Although tumor origin and molecular pathogenesis remain poorly understood, recently established grading and staging systems facilitate patient risk stratification, and thereby directly impact clinical decision making. Although the optimal clinical management of PNETs involves a multidisciplinary approach, surgery remains the only curative treatment for early-stage disease. Surgery may also have a role in patients with advanced-stage disease, including those with hepatic metastases. Alternative therapeutic approaches applied to PNETs, including chemotherapy, radiofrequency ablation, transarterial chemoembolization, biotherapy, polypeptide radionuclide receptor therapy, antiangiogenic therapy, and selective internal radiotherapy, have failed to demonstrate a long-term survival benefit. Surgery remains the primary therapeutic option for patients with PNETs. Research on PNETs is desperately needed to improve the therapeutic options for patients with this disease.

Treatment of Hyperinsulinemic Hypoglycemia Due to Diffuse Nesidioblastosis in Adults: A Case Report

An 82-year-old man was admitted to our hospital with a complaint of hypoglycemic syncope in the early morning. Insulinoma was suspected, but an abdominal CT showed no mass. Abdominal angiography showed a slight stain fed from the splenic artery. Arterial stimulation and venous sampling (ASVS) showed an abnormal insulin response only from the splenic artery. Under a provisional diagnosis of insulinoma, surgical treatment was undertaken. Although no pancreatic masses were palpable, we performed a distal pancreatectomy. Subsequently, a pathological examination revealed diffuse nesidioblastosis. Reported cases of diffuse nesidioblastosis have had common clinical features: postprandial hyperinsulinemic hypoglycemia, no abnormal findings in radiological examinations, and the presence of the ductulo-insular complex on histological examination. Surgical resection is recommended, but the extent of surgery is controversial. Our case had some clinical features of insulinoma but was diagnosed as diffuse nesidioblastosis according to histopathologic criteria. Because ASVS showed that the pancreatic body and tail had a lesion producing insulin abnormally, we performed a distal pancreatectomy to cure the hypoglycemia. Clinically, it is very difficult to distinguish diffuse nesidioblastosis from insulinoma. When we treat hyperinsulinemic hypoglycemia, ASVS can be an essential examination to decide the extent of pancreatectomy.

Evaluation and management of adult hypoglycemic disorders: an Endocrine Society Clinical Practice Guideline

OBJECTIVE

The aim is to provide guidelines for the evaluation and management of adults with hypoglycemic disorders, including those with diabetes mellitus.

EVIDENCE

Using the recommendations of the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system, the quality of evidence is graded very low (plus sign in circle ooo), low (plus sign in circle plus sign in circle oo), moderate (plus sign in circle plus sign in circle plus sign in circle o), or high (plus sign in circle plus sign in circle plus sign in circle plus sign in circle).

CONCLUSIONS

We recommend evaluation and management of hypoglycemia only in patients in whom Whipple's triad--symptoms, signs, or both consistent with hypoglycemia, a low plasma glucose concentration, and resolution of those symptoms or signs after the plasma glucose concentration is raised--is documented. In patients with hypoglycemia without diabetes mellitus, we recommend the following strategy. First, pursue clinical clues to potential hypoglycemic etiologies--drugs, critical illnesses, hormone deficiencies, nonislet cell tumors. In the absence of these causes, the differential diagnosis narrows to accidental, surreptitious, or even malicious hypoglycemia or endogenous hyperinsulinism. In patients suspected of having endogenous hyperinsulinism, measure plasma glucose, insulin, C-peptide, proinsulin, beta-hydroxybutyrate, and circulating oral hypoglycemic agents during an episode of hypoglycemia and measure insulin antibodies. Insulin or insulin secretagogue treatment of diabetes mellitus is the most common cause of hypoglycemia. We recommend the practice of hypoglycemia risk factor reduction--addressing the issue of hypoglycemia, applying the principles of intensive glycemic therapy, and considering both the conventional risk factors and those indicative of compromised defenses against falling plasma glucose concentrations--in persons with diabetes.

Hyperinsulinemic hypoglycemia with nesidioblastosis: histologic features and growth factor expression

Hypoglycemia secondary to nesidioblastosis is rare in adults, and the pathogenesis of this condition is unknown. To determine factors leading to nesidioblastosis in adults, we analyzed 36 cases of nesidioblastosis including 27 cases of postgastric bypass nesidioblastosis and 9 cases of idiopathic nesidioblastosis in adults by immunohistochemistry using antibodies to insulin-like growth factor 1, insulin-like growth factor 2 (IGF2), insulin-like growth factor one receptor-alpha epidermal growth factor receptor, transforming growth factor-beta1 and 2, and transforming growth factor-beta receptor type 3. Fifty-two surgically excised pancreatic specimens from patients with benign exocrine tumors and no evidence of hypoglycemia were used as controls. There was increased IGF2, insulin-like growth factor receptor 1 receptor-alpha and transforming growth factor-beta receptor 3 expression in islets from nesidioblastosis patients compared to controls. Peliosis-type vascular ectasia was more common in nesidioblastosis patients compared to controls. These findings suggest that increased production of growth factors and growth factor receptors may contribute to the development of nesidioblastosis in adults.

A case of nesidioblastosis causing hypoglycaemia after delivery

Nesidioblastosis is a rare cause of adult-onset hyperinsulinaemic hypoglycaemia. We describe a case of nesidioblastosis during pregnancy in a woman receiving medical nutrition therapy for suspected gestational diabetes. However, nesidioblastosis was undiscovered until the development of hypoglycaemia after delivery, being previously masked by pregnancy-related changes in insulin sensitivity.

Non-insulinoma persistent hyperinsulinaemic hypoglycaemia caused by an activating glucokinase mutation: hypoglycaemia unawareness and attacks

OBJECTIVE

Adult-onset non-insulinoma persistent hyperinsulinaemic hypoglycaemia (NI-PHH) and the variant NI-pancreatogenous hypoglycaemia syndrome (NIPHS) are genetically unexplained diseases, without reports of hypoglycaemia unawareness or familial inheritance.

DESIGN AND PATIENTS

In a prospective 8-year follow-up, a boy (i) with NI-PHH since age 14 years, his mother (ii), the mother's brother (iii) and his daughter (iv) were studied.

RESULTS

Patient (i) was characterized by especially postprandial hypoglycaemia down to 1.6 mmol/l and pronounced variability in diazoxide need with obesity; (ii) had asymptomatic blood glucose down to 2.9 mmol/l, but a severe hypoglycaemic postprandial attack after a slimming diet; (iii) had moderate hypoglycaemic symptoms since childhood and need of frequent eating; and (iv) was asymptomatic until a hypoglycaemic accident in the age of 24. After a slimming diet, symptomatic fasting, but especially postprandial hypoglycaemia occurred (blood glucose 1.9 mmol/l after 19 h fasting; 1.6 mmol/l 3.5 h after OGTT). By CT-scan/endoscopic ultrasound in three of the individuals, insulinoma could not be detected. In all four individuals, an activating glucokinase (GCK) mutation A456V was found. No mutations were found in the ABCC8 or KCNJ11 genes. The patients responded to treatment with diazoxide or octreotide long acting release.

CONCLUSION

This is the first report to highlight a genetic cause to adult-onset NI-PHH/NIPHS. The activating GCK mutation was dominantly inherited, but only after year-long follow-up and investigations, other family members were diagnosed symptomatic. Hypoglycaemia unawareness seems to be a prominent feature, but hypoglycaemic attacks occur after slimming, especially postprandially. PHH-GCK was medical responsive.

Severe recurrent hypoglycemia after gastric bypass surgery

BACKGROUND

Bariatric surgery is, at present, the most effective method to achieve major, long-term weight loss in severely obese patients. Recently, severe recurrent symptomatic hyperinsulinemic hypoglycemia was described as a consequence of gastric bypass surgery (GBS) in a small series of patients with severe obesity. Pancreatic nesidioblastosis, a hyperplasia of islet cells, was postulated to be the cause, and subtotal or total pancreatectomy was the suggested treatment.

METHODS

We observed that severe, disabling hypoglycemia after GBS occurred only in patients with loss of restriction. Whether restoration of gastric restriction might treat severe, recurrent hypoglycemia after GBS is unknown.

RESULTS

Therefore, gastric restriction was restored by surgical placement of a silastic ring (n = 8, first two patients with additional distal pancreatectomy) or an adjustable gastric band (n = 4) around the pouch in 12 consecutive patients presenting with severe hypoglycemia (blood glucose below 2.2 mM). At follow-up after restoration of gastric restriction (median follow-up 7 months, range 5 to 19 months), 11 patients demonstrated no hypoglycemic episodes, while one had recurrence of hypoglycemia and underwent distal pancreatectomy. Procedural mortality was 0% and morbidity 8.3%.

CONCLUSION

Patients suffering from severe recurrent hypoglycemia after GBS can be treated, in most cases, just by restoration of gastric restriction. Distal pancreatectomy should be considered a second-line treatment.

Hypoglycaemia in an adult male: a surprising finding in pursuit of insulinoma

A 50-year-old man who had suffered several episodes of early morning sweats and tremors was diagnosed as having hyperinsulinaemic hypoglycaemia. Cross-sectional imaging and endoscopic ultrasound revealed no pancreatic lesion. A selective intra-arterial calcium infusion study showed a two-fold increase of insulin secretion after infusion of the splenic and superior mesenteric arteries. Laparotomy was performed, no lesion was identified after full mobilisation of the pancreas, and nothing was evident with intra-operative ultrasound. A distal pancreatectomy was performed. Microscopically, the pancreas exhibited diffuse islet cell hyperplasia consistent with nesidioblastosis. The patient remains euglycaemic eight months post-operatively.

Endocrine hyperplasia and dysplasia in the pathogenesis of gastrointestinal and pancreatic endocrine tumors

Non-neoplastic proliferative lesions of endocrine cells have been described throughout the gastrointestinal tract and pancreas. A multistep continuum from hyperplasia and dysplasia to neoplasia originally was identified and systematically defined for histamine-producing enterochromaffin-like (ECL) cells of the gastric corpus. More recently, a similar classification system was devised for gastrin (G)- and somatostatin (D)-producing cells in the duodenum. Preneoplastic lesions of the endocrine pancreas still lack a solid and widely accepted definition of a multistep growth process. Similarly, in spite of reports of carcinoid-associated endocrine cell hyperplasia, there is no systematic definition of nonneoplastic lesions of the endocrine cells of the ileum, appendix and colorectum.

Laparoscopic Spleen-Preserving Distal Pancreatectomy as Treatment for Nesidioblastosis after Gastric Bypass Surgery

Nesidioblastosis is characterized by hyperfunction of pancreatic islets caused by hypertrophic beta cells. Postprandial symptoms of hypoglycemia are the clinical presentation of the disease. A female patient with diabetes mellitus who underwent a Roux-en-Y gastric bypass began to present postprandial symptoms of hypoglycemia. There was no radiologic (MRI) evidence of insulinoma. Selective arterial calcium-stimulation test identified hyperfunction only in the splenic artery. Laparoscopic spleen-preserving distal pancreatectomy was performed. The patient has been entirely free of any postprandial symptoms for 10 months after the partial pancreatectomy.

Fluorine-18-L-dihydroxyphenylalanine (18F-DOPA) positron emission tomography as a tool to localize an insulinoma or beta-cell hyperplasia in adult patients

CONTEXT AND OBJECTIVE

Fluorine-18-L-dihydroxyphenylalanine (18F-DOPA) positron emission tomography (PET) is a promising method in localizing neuroendocrine tumors. Recently, it has been shown to differentiate focal forms of congenital hyperinsulinism of infancy. The current study was set up to determine the potential of 18F-DOPA PET in identifying the insulin-secreting tumors or beta-cell hyperplasia of the pancreas in adults.

PATIENTS AND METHODS

We prospectively studied 10 patients with confirmed hyperinsulinemic hypoglycemia and presumed insulin-secreting tumor using 18F-DOPA PET. Anatomical imaging was performed with computed tomography (CT) and magnetic resonance imaging (MRI). All patients were operated on, and histological verification was available in each case. Semiquantitative PET findings in the pancreas using standardized uptake values were compared to standardized uptake values of seven consecutive patients with nonpancreatic neuroendocrine tumors.

RESULTS

By visual inspection of 18F-DOPA PET images, it was possible in nine of 10 patients to localize the pancreatic lesion, subsequently confirmed by histological analysis. 18F-DOPA uptake was enhanced in six of seven solid insulinomas and in the malignant insulinoma and its hepatic metastasis. Two patients with beta-cell hyperplasia showed increased focal uptake of 18F-DOPA in the affected areas. As compared to CT or MRI, 18F-DOPA PET was more sensitive in localizing diseased pancreatic tissue.

CONCLUSION

18F-DOPA PET was useful in most patients with insulinoma and negative CT, MRI, and ultrasound results. In agreement with previous findings in infants, preoperative 18F-DOPA imaging seems to be a method of choice for the detection of beta-cell hyperplasia in adults. It should be considered for the detection of insulinoma or beta-cell hyperplasia in patients with confirmed hyperinsulinemic hypoglycemias when other diagnostic work-up is negative.

Diffuse nesidioblastosis as a cause of hyperinsulinemic hypoglycemia in adults: a diagnostic and therapeutic challenge

Hyperinsulinemic hypoglycemia is caused by uncontrolled insulin release either from neoplastic pancreatic beta-cells or from functionally defective beta-cells. The latter disorder, which is usually seen in newborns, has been called nesidioblastosis and is divided histopathologically into a focal and diffuse type. In adults, nesidioblastosis is rare, and therefore its histopathologic and clinical features are not well known. In our institution, 4 of 128 adult patients (>3%) suffering from hyperinsulinemic hypoglycemia were found to have diffuse nesidioblastosis. The remaining patients had an insulinoma resected successfully in all but one patient. The diagnosis of diffuse nesidioblastosis was established histopathologically after removing a segment of the distal pancreas. Resection of up to 90% of the pancreas relieved 2 of the 4 patients of their symptoms. We conclude that diffuse nesidioblastosis is rare in adults but may account for more than 3% of patients with hyperinsulinemic hypoglycemia. The histopathologic diagnosis relies predominantly on demonstration of beta-cell hypertrophy. The cause of the disease is not known but may be related to defects in the glucose recognition system of the beta-cell. Treatment consists of operative reduction of the beta-cell mass, but the extent of pancreatic resection required is hard to judge, and there is a thin line between successful treatment, persistence of the disease, and pancreatic endocrine insufficiency.

Neonatal hyperinsulinism: clinicopathologic correlation

Neonatal hyperinsulinism is a life-threatening disease that, when treated by total pancreatectomy, leads to diabetes and pancreatic insufficiency. A more conservative approach is now possible since the separation of the disease into a nonrecurring focal form, which is cured by partial surgery, and a diffuse form, which necessitates total pancreas removal only in cases of medical treatment failure. The pathogenesis of the disease is now divided into K-channel disease (hyperinsulinemic hypoglycemia, familial [HHF] 1 and 2), which can mandate surgery, and other metabolic causes, HHF 3 to 6, which are treated medically in most patients. The diffuse form is inherited as a recessive gene on chromosome 11, whereas most cases of the focal form are caused by a sulfonylurea receptor 1 defect inherited from the father, which is associated with a loss of heterozygosity on the corresponding part of the mother's chromosome 11. The rare bifocal forms result from a maternal loss of heterozygosity specific to each focus. Paternal disomy of chromosome 11 is a rare cause of a condition similar to Beckwith-Wiedemann syndrome. A preoperative PET scan with fluorodihydroxyphenylalanine and perioperative frozen-section confirmation are the types of studies done before surgery when needed. Adult variants of the disease are less well defined at the present time.

Hyperinsulinemic hypoglycemia due to adult nesidioblastosis in insulin-dependent diabetes

In neonates, persistent hyperinsulinemic hypoglycemia (PHH) is associated with nesidioblastosis. In adults, PHH is usually caused by solitary benign insulinomas. We report on an adult patient who suffered from insulin-dependent diabetes mellitus, and subsequently developed PHH caused by diffuse nesidioblastosis. Mutations of the MEN1 and Mody 2/3 genes were ruled out. Preoperative diagnostic procedures, the histopathological criteria and the surgical treatment options of adult nesidioblastosis are discussed. So far only one similar case of adult nesidioblastosis subsequent to diabetes mellitus II has been reported in the literature. In case of conversion of diabetes into hyperinsulinemic hypoglycemia syndrome, nesidioblastosis in addition to insulinoma should be considered.

TNM staging of foregut (neuro)endocrine tumors: a consensus proposal including a grading system

The need for standards in the management of patients with endocrine tumors of the digestive system prompted the European Neuroendocrine Tumor Society (ENETS) to organize a first Consensus Conference, which was held in Frascati (Rome) and was based on the recently published ENETS guidelines on the diagnosis and treatment of digestive neuroendocrine tumors (NET). Here, we report the tumor–node–metastasis proposal for foregut NETs of the stomach, duodenum, and pancreas that was designed, discussed, and consensually approved at this conference. In addition, we report the proposal for a working formulation for the grading of digestive NETs based on mitotic count and Ki-67 index. This proposal, which needs to be validated, is meant to help clinicians in the stratification, treatment, and follow-up of patients.

Hyperinsulinemic hypoglycemia after gastric bypass surgery is not accompanied by islet hyperplasia or increased beta-cell turnover

OBJECTIVE

The purpose of this study was to establish whether hypoglycemia after gastric bypass surgery (GBS) for morbid obesity is due to increased fractional beta-cell area or inappropriately increased insulin secretion.

RESEARCH DESIGN AND METHODS

We examined pancreata obtained at partial pancreatectomy from 6 patients with post-GBS hypoglycemia and compared these with 31 pancreata from obese subjects and 16 pancreata from lean control subjects obtained at autopsy. We addressed the following questions. In patients with post-GBS hypoglycemia, is beta-cell area increased and is beta-cell formation increased or beta-cell apoptosis decreased?

RESULTS

We report that in patients with post-GBS hypoglycemia, beta-cell area was not increased compared with that in obese or even lean control subjects. Consistent with this finding, there was no evidence of increased beta-cell formation (islet neogenesis and beta-cell replication) or decreased beta-cell loss in patients with post-GBS hypoglycemia. In control subjects, mean beta-cell nuclear diameter correlated with BMI (r(2) = 0.79, P < 0.001). In patients with post-GBS hypoglycemia, beta-cell nuclear diameter was increased (P < 0.001) compared with that for BMI in matched control subjects but was appropriate for BMI before surgery.

CONCLUSIONS

We conclude that post-GBS hypoglycemia is not due to increases in beta-cell mass or formation. Rather, postprandial hypoglycemia after GBS is due to a combination of gastric dumping and inappropriately increased insulin secretion, either as a failure to adaptively decrease insulin secretion after GBS or as an acquired phenomenon.

Islet Hyperplasia in Adults: Challenge to Preoperatively Diagnose Non-Insulinoma Pancreatogenic Hypoglycemia Syndrome

BACKGROUND

Pancreatic hyperfunctional islet hyperplasia in adults has been more and more frequently described in the literature. Postprandial neuroglycopenia, a negative normal fasting test, negative pancreatic imaging results, and positive intra-arterial calcium stimulation of serum insulin are characteristic. In affected patients the term non-insulinoma pancreatogenic hypoglycemia syndrome (NIPHS) was proposed. MATERIALS AND METHODS/PATIENTS: We also encountered fasting hypoglycemia in such patients and therefore evaluated clinical and biochemical data in patients with NIPHS (n = 11), patients with insulinoma (n = 70), and patients in whom hypoglycemia was ruled out (n = 70).

RESULTS

Patients with NIPHS were younger (median age: 41 years; range: 18-66) and mostly non-obese (median body mass index/BMI: 22.2 kg/m2; range: 19-39) compared with patients with an insulinoma (median age: 50 years; median: BMI 26.1 kg/m2). During an oral glucose tolerance test (OGTT) followed by a standard fasting test, neuroglycopenia was observed postprandially with a mean minimal blood glucose level of 36 +/- 9 mg/dl in 7 out of 11 patients. Spontaneous hypoglycemia during the fast was 38 +/- 5 mg/dl in 8 out of 11 patients. The corresponding insulin levels were 9.2 +/- 9.8 mU/l (OGTT) and 6.8 +/- 5.4 mU/l (fasting), significantly lower than in patients with insulinoma (P < 0.001), but not different from patients without hypoglycemia (P = 0.05). After pancreatic resection 8 patients (73%) were cured with enduring euglycemia. Pathohistological islet abnormalities with hyperplasia, hypertrophy, and microadenomatosis were confirmed in all patients.

CONCLUSION

In patients with postprandial and/or fasting neuroglycopenia NIPHS may be suspected when insulin levels are low but inadequately suppressed and localization studies failed to show a distinct pancreatic tumor.

A case of hyperinsulinemia of undetermined origin, successfully treated with long-acting octreotide

Major causes of fasting hypoglycemia in adults are insulinoma, factitious hypoglycemia and nesidioblastosis. The primary treatment for insulinoma is surgical removal of the tumor, but there are cases with hyperinsulinemia that cannot undergo surgery. Somatostatin analogue is one of the treatments used in such cases of insulinoma or persistent hyperinsulinemic hypoglycemia. We report here a patient who had undetermined hyperinsulinemia and was successfully treated with a long-acting somatostatin analogue, which had recently become available. The patient, a 72-year-old female, who had previously been diagnosed as insulinoma and undergone partial pancreatectomy, was admitted complaining of the recurrence of hypoglycemic attacks after an interval of ten years. On admission, hypoglycemia (42 mg/dl), hyperinsulinemia (IRI: 79.3 microU/m) and low HbA1c (3.6%) were present. In 75 g-OGTT at 30 min after load, IRI reached 6623 microU/ml, while plasma glucose level was 88 mg/dl. The anti-insulin antibody was not present. Since attempts at tumor localization by imaging techniques failed and the patient refused further examinations or surgical treatment, we recommended her to take a medication with a somatostatin analogue. Insulin suppression test using 50 microg of octreotide improved plasma glucose and IRI levels, suggesting the usefulness of the treatment, and a monthly administration of 20 mg of long-acting octreotide has successfully controlled her symptoms of hypoglycemia for 10 months. Our case demonstrated the utility of the long-acting somatostatin analogue for long-term treatment of undetermined hyperinsulinemia. A preliminary loading test using short-acting octreotide may be useful to determine appropriate medication, especially in cases who cannot receive surgical treatment.