Nesidioblastosis in an adult with hyperinsulinemic hypoglycemia

Diffuse, Adult-Onset Nesidioblastosis/Non-Insulinoma Pancreatogenous Hypoglycemia Syndrome (NIPHS): Review of the Literature of a Rare Cause of Hyperinsulinemic Hypoglycemia

Differential diagnosis of hypoglycemia in the non-diabetic adult patient is complex and comprises various diseases, including endogenous hyperinsulinism caused by functional β-cell disorders. The latter is also designated as nesidioblastosis or non-insulinoma pancreatogenous hypoglycemia syndrome (NIPHS). Clinically, this rare disease presents with unspecific adrenergic and neuroglycopenic symptoms and is, therefore, often overlooked. A combination of careful clinical assessment, oral glucose tolerance testing, 72 h fasting, sectional and functional imaging, and invasive insulin measurements can lead to the correct diagnosis. Due to a lack of a pathophysiological understanding of the condition, conservative treatment options are limited and mostly ineffective. Therefore, nearly all patients currently undergo surgical resection of parts or the entire pancreas. Consequently, apart from faster diagnosis, more elaborate and less invasive treatment options are needed to relieve the patients from the dangerous and devastating symptoms. Based on a case of a 23-year-old man presenting with this disease in our department, we performed an extensive review of the medical literature dealing with this condition and herein presented a comprehensive discussion of this interesting disease, including all aspects from epidemiology to therapy.

Clinical features and morphological characterization of 10 patients with noninsulinoma pancreatogenous hypoglycaemia syndrome (NIPHS)

OBJECTIVE

Noninsulinoma pancreatogenous hypoglycaemia syndrome (NIPHS), characterized by postprandial neuroglycopaenia, negative prolonged fasts and negative perioperative localization studies for insulinoma, but positive selective arterial calcium stimulation tests and nesidioblastosis in the gradient-guided resected pancreas, is a rare hypoglycaemic disorder of undetermined aetiology. We analysed the clinical, morphological and immunohistological features to further clarify the aetiology and pathogenesis of this rare disease.

PATIENTS

Ten consecutive patients with NIPHS (nine men and one woman, aged 29-78 years) were included in the study. Six of the 10 received a gradient-guided subtotal (70%) or distal (50%) pancreatectomy. In the remaining four patients, diazoxide treatment was initiated and the precise mechanism of its action was assessed by meal tests.

RESULTS

All of the patients showed a combination of postprandial neuroglycopaenia, negative prolonged fasts (except one patient) and negative localization studies for insulinoma, but positive calcium stimulation tests and nesidioblastosis in the gradient-guided resected pancreas. Immunohistological studies of the resected pancreatic tissues revealed neither an increased rate of proliferation of beta-cells nor an abnormal synthesis and/or processing of either proinsulin or amylin. Evidence of overexpression of the two pancreatic differentiation factors, PDX-1 and Nkx-6.1, as well as the calcium sensing receptor (CaSR) was absent. Nevertheless, abnormal expression of islet neogenesis-associated protein (INGAP), a human cytokine expressed only in the presence of islet neogenesis, in ducts and/or islets, was identified in three of the five patients studied. All of the six patients who received a surgical operation were relieved of further neuroglycopaenic attacks, but one patient who received a subtotal pancreatectomy developed diabetes. In the remaining four patients who received diazoxide treatment, hypoglycaemic episodes were satisfactorily controlled with an attenuated response of beta-cell peptides to meal stimulation.

CONCLUSIONS

Our results strengthen the existence of this unique clinical hypoglycaemic syndrome from beta-cell hyperfunction as well as the value of the selective arterial calcium stimulation test in its correct diagnosis and localization. The mechanisms underlying beta-cell hyperfunction and release of insulin to calcium, however, remain poorly characterized. Nevertheless, in a subset of patients with NIPHS, there exists some, as yet undefined, pancreatic humoral/paracrine factor(s) other than proinsulin, amylin, PDX-1, Nkx-6.1 and possibly glucagon-like peptide-1 (GLP-1) that are capable of inducing the INGAP gene and, if activated, will initiate ductal proliferation and islet neogenesis. As for the treatment, we recommend that diazoxide be tried first in each patient and, should it fail, a gradient-guided subtotal or distal pancreatectomy be attempted.

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.

Nesidioblastosis associated with hyperinsulinemic hypoglycemia in adults: review of the literature

Nesidioblastosis is a term that was first introduced by Laidlaw in 1938 to define the diffuse proliferation of pancreatic islet cells budding from ductal epithelium. First described in neonates, it is widely recognized to be the primary cause of persistent hyperinsulinemic hypoglycemia in infants. In adults, insulinoma accounts for most cases of hyperinsulinemic hypoglycemia. Adult-onset nesidioblastosis associated with hyperinsulinemic hypoglycemia is a very rare entity, representing 0.5-5% of cases of organic hyperinsulinemia. Since 1981, when Harness et al. reported the first series of adult nesidioblastosis causing hypoglycemia, only 71 cases have been published. This article provides a guide for the diagnosis of organic hyperinsulinism and indicates when nesidioblastosis should be suspected. New diagnostic methods and treatment options for this rare disease are proposed. We also present a review of all reported cases of adult nesidioblastosis in the last 22 years.

Surgical treatment of insulinomas

Differential diagnosis of hypoglycemic patients should include insulinoma. Plasma insulin-to-glucose ratio greater than 0.3 or C-peptide levels of 2 nmol/L or greater suggest insulinoma. Abdominal CT scan can exclude metastatic disease and identify uncommonly large islet cell tumors, but has poor sensitivity for localizing insulinomas; transgastric endoscopic ultrasound is the most sensitive technique. Palpation combined with intraoperative ultrasound identifies most tumors at operation and gives vital information about surrounding structures. If no tumor is found, blind distal pancreatectomy should not be performed, and the patient should be referred to an endocrinologist or endocrine surgeon for diagnostic confirmation and further localization. Laparoscopy is a viable alternative to open tumor resection; laparoscopic ultrasound can facilitate localization and guide safe resection.

Hyperinsulinism in Infancy: From Basic Science to Clinical Disease

Dunne, Mark J., Karen E. Cosgrove, Ruth M. Shepherd, Albert Aynsley-Green, and Keith J. Lindley. Hyperinsulinism in Infancy: From Basic Science to Clinical Disease. Physiol Rev 84: 239–275, 2004; 10.1152/physrev.00022.2003.—Ion channelopathies have now been described in many well-characterized cell types including neurons, myocytes, epithelial cells, and endocrine cells. However, in only a few cases has the relationship between altered ion channel function, cell biology, and clinical disease been defined. Hyperinsulinism in infancy (HI) is a rare, potentially lethal condition of the newborn and early childhood. The causes of HI are varied and numerous, but in almost all cases they share a common target protein, the ATP-sensitive K+channel. From gene defects in ion channel subunits to defects in β-cell metabolism and anaplerosis, this review describes the relationship between pathogenesis and clinical medicine. Until recently, HI was generally considered an orphan disease, but as parallel defects in ion channels, enzymes, and metabolic pathways also give rise to diabetes and impaired insulin release, the HI paradigm has wider implications for more common disorders of the endocrine pancreas and the molecular physiology of ion transport.

Noninsulinoma pancreatogenous hypoglycemia syndrome: an update in 10 surgically treated patients

BACKGROUND

Neuroglycopenia from endogenous hyperinsulinism usually is caused by insulinomas in adults. We recently reported a novel hypoglycemic disorder in 5 patients (patients 1 to 5) with postprandial neuroglycopenia, negative 72-hour fasts, negative perioperative imaging studies, but positive calcium stimulation tests and islet hypertrophy and nesidioblastosis in the gradient-guided resected pancreata.

METHODS

In this report we compare our experience with 5 additional patients (patients 6 to 10) with this syndrome to that in the original report.

RESULTS

The clinical features of patients 6 to 10 were similar to those of patients 1 to 5. Each had positive calcium stimulation testing that guided the extent of the distal pancreatectomy and histologic evidence of islet cell hypertrophy or nesidioblastosis. All 10 patients are alive from 9 to 50 months after operation, 1 of whom had no amelioration of neuroglycopenia. Minor perioperative complications occurred in 3 patients. One patient has experienced repeated bouts of acute pancreatitis, pseudocyst formation, and exocrine insufficiency.

CONCLUSIONS

We have identified adult patients with severe, postprandial hyperinsulinemic hypoglycemia from diffuse islet cell disease, 80% of whom have been well palliated with surgery. The results in 7 men have been better than those in the 3 women for reasons that are not obvious.

Nesidioblastosis with hyperinsulinemic hypoglycemia in adults: report of two cases

We report herein the cases of two women, aged 34 years and 39 years, respectively, found to have hyperinsulinemic hypoglycemia after presenting with a history of episodes of temporary loss of consciousness, nausea, and fainting. Under the suspected diagnosis of insulinoma, localization procedures were carried out, but no tumor was found. In both patients, a definite gradient in insulin concentration was found in the pancreas by percutaneous transhepatic or intraoperative portal venous sampling, and a misdiagnosis of insulinoma of the pancreatic body was made. During exploratory laparotomy no tumor was palpable in the pancreas, and intraoperative ultrasonography showed no low echoic mass in the pancreas. A distal pancreatectomy was performed in both patients, and histopathological examination of the resected specimens revealed graded slight hyperplasia of the islet cells.