Nesidioblastosis and Subsequent Diabetes Mellitus in a Dog with Hyperinsulinemic Hypoglycemia Treated with Partial Pancreatectomy

A 6.5 yr old castrated male mixed-breed dog was presented for clinical signs associated with hypoglycemia. Hyperinsulinemic hypoglycemia was diagnosed as the cause of the persistent hypoglycemia. No obvious pancreatic mass was seen on abdominal computed tomography and exploratory laparotomy. A partial pancreatectomy was performed with the suspicion of an insulinoma-causing hyperinsulinemic hypoglycemia. Nesidioblastosis was diagnosed based clinical, biochemical, and histopathologic findings. There was beta cell hyperplasia and no evidence of neoplasia. The dog was euglycemic postoperatively after a partial pancreatectomy. Long-term follow-up after 2 yr revealed that the dog was diagnosed with diabetes mellitus.

Pathological features in non-neoplastic congenital and adult hyperinsulinism: from nesidioblastosis to current terminology and understanding

Nesidioblastoma and nesidioblastosis were terms given to neoplastic and non-neoplastic lesions of the pancreas associated with pancreatogenous hyperinsulinaemic hypoglycaemia. While nesidioblastoma was rapidly replaced by islet cell tumour, nesidioblastosis, defined as the proliferation of islet cells budding off from pancreatic ducts, was the diagnostic term associated with congenital hyperinsulinism of infancy (CHI) and adult non-neoplastic hyperinsulinaemic hypoglycaemia (ANHH). When it was shown that nesidioblastosis was not specific for CHI or ANHH, it was no longer applied to CHI but kept for the morphological diagnosis of ANHH. In severe CHI cases, a diffuse form with hypertrophic ß-cells in all islets can be distinguished from a focal form with hyperactive ß-cells changes in a limited adenomatoid hyperplastic area. Genetically, mutations were identified in several ß-cell genes involved in insulin secretion. Most common are mutations in the ABCC8 or KCNJ11 genes, solely affected in the diffuse form and associated with a focal maternal allelic loss on 11p15.5 in the focal form. Focal CHI can be localized by 18F-DOPA-PET and is thus curable by targeted resection. Diffuse CHI that fails medical treatment requires subtotal pancreatectomy. In ANHH, an idiopathic form can be distinguished from a form associated with gastric bypass, in whom GLP1-induced stimulation of the ß-cells is discussed. While the ß-cells in idiopathic ANHH are diffusely affected and are either hypertrophic or show only little changes, it is controversial whether there is a ß-cell increase or ß-cell hyperactivity in patients with gastric bypass. Recognizing morphological signs of ß-cell hyperactivity needs a good knowledge of the non-neoplastic endocrine pancreas across all ages.

Nesidioblastosis and Insulinoma: A Rare Coexistence and a Therapeutic Challenge

Background: Nesidioblastosis and insulinoma are disorders of the endocrine pancreas causing endogenous hyperinsulinemic hypoglycemia. Their coexistence is very unusual and treatment represents a still unresolved dilemma. Case Description: The patient was a 43-year-old Caucasian woman, with a 2-year history of repeated severe hypoglycemic events. The diagnostic work-up was strongly suggestive of insulinoma and the patient was submitted to surgical treatment carried out laparoscopically under robotic assistance. However, surgical exploration and intraoperative ultrasonography failed to detect a pancreatic tumor. Resection was therefore carried out based on the results of selective intra-arterial calcium stimulation test, following a step-up approach, eventually leading to a pancreatoduodenectomy at the splenic artery. The histopathology examination and the immunohistochemical staining were consistent with adult-onset nesidioblastosis. After surgery, the patient continued to experience hypoglycemia with futile response to medical treatments (octreotide, calcium antagonists, diazoxide, and prednisone). Following multidisciplinary evaluation and critical review of a repeat abdominal computed tomography scan, a small nodular lesion was identified in the tail of the pancreas. The nodule was enucleated laparoscopically and the pathological examination revealed an insulinoma. In spite of the insulinoma resection, glycemic values were only partially restored, with residual nocturnal hypoglycemia. Administration of uncooked cornstarch (1.25 g/kg body weight) at bedtime was associated with significant improvement of interstitial glucose levels (p < 0.0001) and reduction of nocturnal hypoglycemia episodes (p = 0.0002). Conclusions: This report describes a rare coexistence of adult-onset nesidioblastosis and insulinoma, suggesting the existence of a wide and continuous spectrum of proliferative β-cell changes. Moreover, we propose that uncooked cornstarch may offer an additional approach to alleviate the hypoglycemic episodes when surgery is impracticable/unaccepted.

Resolution of hyperinsulinemic hypoglycemia following partial pancreatectomy in a dog with nesidioblastosis

CASE DESCRIPTION A 6-year-old castrated male Australian Shepherd was evaluated because of a recent onset of persistent hypoglycemia. CLINICAL FINDINGS Physical examination results were generally unremarkable. No abnormalities were detected on thoracic radiographs, and abdominal ultrasonography revealed no obvious pancreatic lesion. Hematologic analysis revealed hypoglycemia with a high serum insulin-to-glucose concentration ratio. TREATMENT AND OUTCOME Insulinoma was suspected; medical treatment with prednisone was initiated, and exploratory laparotomy was performed. No pancreatic lesions or masses were observed. Partial left pancreatectomy and hepatic and local lymph node biopsies were performed. Histologic examination revealed islet cell hypertrophy and hyperplasia, with no evidence of neoplasia. Results of a PCR assay of the pancreatic tissue for Bartonella infection were negative. Clinical, biochemical, and histopathologic findings were compatible with nesidioblastosis. The clinical signs, including hypoglycemia, resolved after surgery. On follow-up examination 8 months later, the dog was apparently healthy and results of a CBC and serum biochemical analysis, including blood glucose concentration, were within respective reference ranges. CLINICAL RELEVANCE To our knowledge, this is the first report of nesidioblastosis in a dog for which clinical signs and clinicopathologic abnormalities resolved after partial pancreatectomy. Although extremely rare, nesidioblastosis should be considered a differential diagnosis in dogs with signs suggestive of insulinoma.

Hyperinsulinemic Hypoglycemia after Bariatric Surgery: Diagnosis and Management Experience from a Spanish Multicenter Registry

BACKGROUND

Severe postprandial hypoglycemia after bariatric surgery is a rare but invalidating complication. Our aim was to describe the different tests performed for its diagnosis and their outcomes as well as the response to the prescribed pharmacological and surgical treatments.

METHODS

Multicenter, retrospective systematic review of cases with recurrent severe postprandial hypoglycemia.

RESULTS

Over 11 years of follow-up, 22 patients were identified. The test most used to provoke hypoglycemia was the oral glucose load test followed by the mixed meal test which was the least standardized test. With pharmacological treatment, 3 patients were symptom-free (with octreotide) and in 12 patients hypoglycemic episodes were attenuated. Seven patients had persistent hypoglycemic episodes and underwent surgery. Partial pancreatectomy was performed in 3 patients who had positive selective arterial calcium stimulation, and nesidioblastosis was confirmed in 2 patients. Reconversion to normal anatomy was performed in 3 patients, and 1 patient underwent a resection of the 'candy cane' roux limb, with resolution of hypoglycemia in all cases.

CONCLUSIONS

There is high heterogeneity in the evaluation and treatment options for postoperative hypoglycemia. In patients that do not respond to pharmacological treatment, reconstruction of gastrojejunal continuity may be the safest and most successful procedure.

Selective Arterial Calcium Stimulation With Hepatic Venous Sampling Differentiates Insulinoma From Nesidioblastosis

CONTEXT

In adult patients with endogenous hyperinsulinemic hypoglycemia and negative or inconclusive noninvasive imaging, insulinoma and non-insulinoma pancreatogenous hypoglycemic syndrome (NIPHS) resulting from diffuse nesidioblastosis must be considered in the differential diagnosis. It is not known whether the biochemical results of selective arterial calcium stimulation (SACST) with hepatic venous sampling can differentiate insulinoma from diffuse nesidioblastosis.

OBJECTIVE

To determine the specificity of SACST with hepatic venous sampling in differentiating insulinoma from diffuse nesidioblastosis.

DESIGN

Retrospective review (January 1996 to March 2014).

SETTING

Tertiary referral center.

PATIENTS OR OTHER PARTICIPANTS

A total of 116 patients with biochemical evidence of endogenous hyperinsulinemic hypoglycemia and negative or inconclusive noninvasive imaging who were subsequently shown at surgery to have insulinoma (n = 42) or nesidioblastosis (n = 74) after undergoing SACST with hepatic venous sampling.

INTERVENTION(S)

SACST with hepatic venous sampling before pancreatic exploration.

MAIN OUTCOME MEASURE(S)

Receiver operating characteristic curves were generated from the biochemical results of SACST to determine the specificity of the maximum hepatic venous insulin concentration (mHVI) and the relative-fold increase in hepatic venous insulin concentration (rHVI) over baseline after calcium injection from the dominant artery in differentiating insulinoma from nesidioblastosis.

RESULTS

The mHVI (21.5-fold; P < .001) and rHVI (3.9-fold; P < .001) were significantly higher in the insulinoma group compared to the nesidioblastosis group. The areas under the receiver operating characteristic curve for mHVI and rHVI were excellent (0.94; P < .0001) and good (0.83; P < .0001), respectively, for differentiating insulinoma from nesidioblastosis. mHVI cutoffs of > 91.5 and > 263.5 μIU/mL were 95 and 100% specific for insulinoma, respectively. A 19-fold increase in rHVI over baseline was 99% specific for insulinoma.

CONCLUSIONS

These data suggest that the mHVI and rHVI at SACST may be useful in differentiating insulinoma from nesidioblastosis with high specificity in patients with hyperinsulinemic hypoglycemia and negative or inconclusive noninvasive imaging.

Pathological aspects underlying pancreatogenous hyperinsulinemic hypoglycemia--report of three cases

Pancreatogenous hyperinsulinemic hypoglycemia (PHH) is a rare disorder determined by an abnormally high secretion of insulin in the pancreas, in the absence of other medical or pharmacological factors. Either β-cell tumors (insulinomas) or β-cell hyperplasia (nesidioblastosis) can determine this pathology. Most publications on insulinomas or nesidioblastosis approached these subjects from a clinical point of view. This paper aims to analyze pathological aspects underlying pancreatogenous hyperinsulinemic hypoglycemia. We present two cases of insulinomas with unusual pancreatic localization and size, one of them showing amyloid deposits in the stroma. In both cases, immunohistochemistry confirmed the clinical and imagistic supposition. The third reported case refers to a 57-year-old patient with nesidioblastosis with isolated disposition of endocrine cells and areas of focal organization, both morphological aspects being extremely rare in adults. Although clinical and laboratory data are usually identical in the two forms of PHH, histopathological and immunohistochemical diagnosis is essential in differentiating insulinomas from nesidioblastosis, as the surgical management is different: enucleation for insulinomas and total or subtotal pancreatectomy for nesidioblastosis.

[Symptoms and early diagnostic possibilities of pancreatic endocrine cells hyperplasia (nesidioblastosis)]

Nesidioplastosis in adults is one of a rare causes of hyperinsulinemic hypoglycemia. Symptoms include chronic or recurrent hypoglycemias, often with neurological signs. Due to the looses of consciousness with coexisting seizures, in many cases patients are treated on epilepsy. Right diagnosis is usually late established, when the damages in the central nervous system (CNS) are irreversible. Early diagnosis of the disease and appropriate treatment might help to avoid serious disability in these patients. The aim of the study was to asses modern diagnostics of the nesidioblastosis with an emphasis on the biochemical and hormonal tests and imaging modalities. Patients enrolled to the study were aged between 18 and 72 years of age, and had chronic or recurrent hypoglycemia caused by hyperinsulinemia. In all patients fasting glucose and fasting insulinemia tests were performed, as well as the fasting blood test or in the 24-hour profile tests. Several techniques were used including ultrasound (US), abdominal computer tomography (CT), in two patients magnetic resonance imaging, scintigraphy of somatostatin receptors in seven patients, and in two patients scintigraphy with glucagone-like peptide-1 (GLP-1) analogue-labeled marker was done. In the performed tests low values of the blood glucose were found, whereas insulin levels, however not adequate to the blood glucose, were nearly always within the normal range. In the standard imaging only in one patient tumor lesion in the pancreatic tail was revealed, though not confirmed in the intraoperative histology. In the scintigraphy examination with the somatostatin analogue in one patient slightly increased collection of the marker in whole pancreas was reported and in the other patient focal collection in the pancreatic tail was observed. Scintigraphy with GLP-1 analogue revealed focal collection of the marker in one case. Five patients were underwent surgical treatment. In the histopathology in all operated patients hyperplasia of the endocrine pancreatic cells with positive immuno. histochemic reaction on the insulin was found. In the three cases despite hyperplasia of pancreatic islets, small sizes insulinomas were detected as well. 1. The diagnosis of nesidioblastosis should be taken into consideration in all patients with unclear-cause hypoglycemias, in whom simultaneously insulin blood level is inadequate to the level of glucose. 2. Widely available imaging examinations: US, CT, MRI are useless in the diagnosis of nesidioblastosis. 3. Among the imaging methods in preoperative diagnostics of hypoglycemia with concomitant hyperinsulinemia somatostatin receptor scintigraphy seems to have specific, though limited role - it is valuable only in the severe, diffused lesions. 4. Recurrent hypoglycemias after 70% excision of the pancreas may indicate the possibility of coexistence of pancreatic islets hyperplasia and insulin secreting insulinoma.

Congenital disorder of glycosylation type Ia: heterogeneity in the clinical presentation from multivisceral failure to hyperinsulinaemic hypoglycaemia as leading symptoms in three infants with phosphomannomutase deficiency

We describe three patients with congenital disorder of glycosylation (CDG) type Ia, all of whom had persistent hyperinsulinaemic hypoglycaemia responding to diazoxide therapy as a common feature. The first patient, an infant girl, presented with recurrent vomiting, failure to thrive, liver impairment, hypothyroidism and a pericardial effusion. The second patient, also female, had a milder disease with single organ involvement, presenting as isolated hyperinsulinaemic hypoglycaemia, not associated with any cognitive impairment. The third patient, a boy presented with multi-organ manifestations including congenital hypothyroidism, persistent hyperinsulinaemic hypoglycaemia, coagulopathy, olivopontocerebellar hypoplasia and recurrent pancreatitis. All three patients had a type 1 serum transferrin isoform pattern, and were subsequently found to have low phosphomannomutase activity, confirming the diagnosis of CDG type Ia. Our findings emphasize that CDG should be considered as a differential diagnosis in patients with persistent hyperinsulinaemic hypoglycaemia and that it may even occasionally be the leading symptom in CDG Ia.

[Nesidioblastosis in an adult with type 2 diabetes mellitus: a case report]

Adults-onset nesidioblastosis, as a differential diagnosis of organic hyperinsulinemic hypoglycemia, is very rare and has been recognised as "noninsulinoma pancreatogenous hypoglycaemia syndrome (NIPHS)". Here we described an extremely rare case of NIPHS in an elderly type 2 diabetes mellitus with insulin therapy. A 84-year old male was diagnosed as type 2 diabetes six years ago and switched from an oral hypoglycemic drug to pro-mixed insulin treatment 3 years ago. According to medical records, he had good-glucose control over few hypoglycemia. He was admitted to hospital due to frequent fasting hypoglycaemic episodes and comas despite withdrawal of any anti-diabetes drugs and continuous infusion of homogenate meal at night. Lab test showed low fasting glucose level and inappropriate high insulin/C-peptide level, and anti-insulin antibody was negative. A characteristic of hyperinsulinemic hypoglycemia with high C-peptide level was consistent with the possible diagnosis of insulinoma, but localizing studies including computed tomography of the abdomen and somatostatin receptor scintigraphy were negative. Surgical exploration by the palpation and intraoperative ultrasonography failed to detect any mass in the pancreas and 70% distal pancreatectomy was performed. Histological examination of the resected pancrease revealed an increased number and size of islets consistent with nesidioblastosis. After transient decline, his serum insulin travelled back to the level before pancreaectomy, but recurrent fasting hypoglycemia was mild and controlled by regular night eating postpancreaectomy.

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.

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.

An unusual case of concurrent insulinoma and nesidioblastosis

CONTEXT

Endogenous hyperinsulinaemic hypoglycaemia in adults is most commonly caused by an insulinoma. Adult nesidioblastosis is rarely reported. To the best of our knowledge the presence of both insulinoma and nesidioblastosis has not been reported before.

CASE REPORT

We report a case of a 35-year-old female presenting with neuroglycaemic symptoms. A supervised 72-hour fast confirmed hypoglycaemia in the presence of hyperinsulinaemia. Thorough pre-operative biochemical and radiological investigations, including selective splenic, superior mesenteric and portal venous sampling inferred a tentative diagnosis of adult nesidioblastosis. However, a grossly elevated insulin level within the splenic vein on a second set of venous sampling produced a high index of suspicion for the presence of an insulinoma. At surgical exploration both an insulinoma and nesidioblastosis were identified and confirmed by histological examination.

CONCLUSION

We report an even rarer entity of concurrent insulinoma and nesidioblastosis.

Adult nesidioblastosis. Clinicopathologic correlation between pre-operative selective arterial calcium stimulation studies and post-operative pathologic findings

CONTEXT

Adult nesidioblastosis, a rare form of abnormal islet cell proliferation arising from the pancreatic ductal epithelium, is usually associated with severe hyperinsulinemic hypoglycemia. Overall, seventy-three cases of nesidioblastosis have been described in the English literature since the entity was first described by Laidlaw in 1938, and only a minute fraction of these have occurred in children.

CASE REPORT

We present the case of a previously healthy 45-year-old woman with new-onset severe hypoglycemia 4 and seizures. The differential diagnosis at presentation included factitious hypoglycemia and insulinoma. Extensive imaging and laboratory examination, including repeated CT and MRI scans, toxicology assays, and insulin-based chemical studies, were either inconclusive or negative. Subsequent testing involved stimulation of the pancreas through cannulation of the pancreatic vascular supply by interventional radiology. This testing revealed marked insulin release to low-level calcium challenge across multiple pancreatic segments. Based on these functional radiological findings, the patient underwent subtotal pancreatectomy. Gross and histologic examination of the resected tissue revealed no evidence of a pancreatic mass. Diffuse islet cell hyperplasia was noted in a pattern consistent with nesidioblastosis. The patient remained normoglycemic in the months following partial pancreatectomy.

CONCLUSIONS

Nesidioblastosis, while exceedingly rare in adult populations, should be considered in the differential diagnosis of severe hypoglycemia. This diagnosis cannot be easily made through routine diagnostic laboratory or radiological procedures and likely requires a histological tissue diagnosis.

[Endogenous persistent hypoglicemia of adult: case report]

Persistent Hyperinsulinemic Endogenous hypoglycemia in adults is, in most cases, due to Insulinoma. Nesidioblastosis, a peculiar functional hyperinsulinemia from hypertrophic beta cells, has been described mainly in newborns. This article describes a 34-year-old patient who presented hyperinsulinemic endogenous hypoglycemia clinical and laboratorial situation (Fasting glycemia: 54 mg/dl / Reference Interval (RI): 60-99 mg/dl; Serum insulin: 70.9 mcU/ml / RI: < 29.1 mcU/ml; e C peptide: 7.1 ng/ml / RI: 1.1-5.0 ng/ml). It was suspected Insulinoma. Because of the lack of typical images in radiologic exams (ultrasonography and computerized tomography) it had been decided to do laparotomy, but it was not found any macroscopic pancreatic tumor. Histological and histochemistry examination of a distal pancreatic segment showed alteration suitable to nesidioblastosis. The patient presented clinical stability during the next two months, however, after that, there was a recurrence of a hypoglycemia crisis, refractory to Octreotide administration. It was done "octreoscan", which showed expanded nesidioblastosis, being done extensive partial pancreatectomy. Octreotide was used again, with a good control of the hypoglycemia crisis. As it is an uncommon diagnosis in an adult, the objective of this article is to describe the diagnostic and therapeutic aspects in cases of hyperinsulinemic endogenous hypoglicemia.

The role of intra-arterial calcium stimulation test with hepatic venous sampling (IACS) in the management of occult insulinomas

BACKGROUND

Occult insulinomas remain a clinical challenge. Specifically designed protocols are necessary to aid detection and facilitate a focused pancreatic exploration.

METHODS

Seventeen non-multiple endocrine neoplasia (non-MEN) patients referred to this medical center in the past 10 years because of equivocal diagnosis, failure of previous operation or difficulty in localization for insulinomas were studied. A routine intra-arterial calcium stimulation test with venous sampling (IACS test) was done for lesion localization. An exploratory laparotomy with intraoperative ultrasound (IOUS) examinations was performed.

RESULTS

Preoperative imaging (sonography, high-resolution computed tomography scan, and magnetic resonance imaging) found six insulinomas, and IOUS found an additional six in the pancreatic regions; all were compatibly indicated by the IACS test. The remaining five patients with occult lesions by IOUS were treated by 40% (1) or 60-70% (4) distal pancreatectomies when insulin gradients were demonstrated on calcium stimulation to the splenic or to the superior mesenteric artery, respectively, and nesidioblastosis was found in each pathology examination. There were no complications related to the arterial stimulation and venous sampling (ASVS) test. No patient had recurrent hyperinsulinism, permanent morbidity, or mortality from surgery.

CONCLUSIONS

IACS test helps in the diagnosis of equivocal pancreatogenous hypoglycemia, indicating the pancreatic region of priority exploration and guiding a pancreatic resection.

Surgical treatment of persistent hyperinsulinemic hypoglycemia (PHH) (insulinoma and nesidioblastosis)

BACKGROUND

The persistent hyperinsulinemic hypoglycemia is characterized by clinical symptoms that occur when the blood glucose levels drop below the normal range. Two pathological situations cause this clinical problem: The presence of a tumor of the pancreas secreting excessive amounts of insulin, known as insulinoma, and congenital beta-cell hyperplasia in the pancreas in children and noninsulinoma pancreatogenic hypoglycemia syndrome in adults.

PATIENTS AND METHODS

Clinical characteristic and surgical outcome of a group of 20 patients operated on for this hypoglycemic syndrome; 18 for insulinoma and two for nesidioblastosis in children was studied.

RESULTS

eight of the insulinomas were in the head of the pancreas, two in the body, and the remaining eight in the tail. The surgical technique was enucleation in nine cases, local resection in one case because of suspicious malignancy, and distal pancreatectomy in eight cases. Both children with nesidioblastosis underwent 85% pancreatectomy with splenic preservation. There was no mortality in the study, but three patients developed a low-volume pancreatic fistula after head enucleation.

CONCLUSIONS

Negative results in diagnostic localization together with the small size of the insulinoma represent a poor combination for successful surgery. The intraoperative ultrasonography is the method of choice for the identification of the tumor, as it is able to identify nonpalpable lesions.

Recurrent hypoglycaemia in HIV-positive narcotic addicts

QUESTIONS UNDER STUDY

We describe two narcotic addict women with recurrent hypoglycaemic episodes. In both patients, hyperinsulinaemic hypoglycaemia occurring in the fasting state was documented and computed tomography of the pancreas was normal.

METHODS AND RESULTS

In patient 1, selective arterial calcium stimulation with hepatic venous sampling (ASVS) revealed pronounced insulin hypersecretion predominantly in the tail and, to a lesser extent, in the corpus and the head of the pancreas. On laparoscopic exploration, tumours could not be detected be it grossly or by intraoperative ultrasound. Distal pancreatectomy was performed laparoscopically, and histological examination of the resected tissue revealed nesidioblastosis. ASVS was also performed in patient 2 revealing less marked increases in insulin secretion, ie up to 2.3-fold in response to calcium stimulation of the superior mesenteric artery, consistent with the presence of pathological beta-cells located predominantly in the head of the pancreas. Surgical exploration was not performed in this patient.

CONCLUSION

HIV infection had been known in both women for around ten years and both patients were not on antiretroviral therapy. Because symptomatic nesidioblastosis in adult patients is a very rare disorder, we speculate that nesidioblastosis may develop in the context of HIV infection and/or abuse of narcotic drugs. Our observations illustrate that neurocognitive impairment in HIV positive patients is not always due to toxic compounds or a cerebral disorder but may be caused by an apparently rare pancreatic disorder, nesidioblastosis. Thus, the patients should be checked for the presence of hyperinsulinaemic hypoglycaemia.

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.

A rare case of adult-onset nesidioblastosis treated successfully with diazoxide

A 54-year-old man was admitted to our hospital for evaluation of hypoglycemia. He had frequent episodes of loss of concentration before dinner. The ratio of IRI to plasma glucose (PG) was 0.8-1.0. Abdominal CT revealed no pancreatic tumor, and angiography of splenic artery showed no definite tumor stain within the pancreas. Based on the results of selective arterial calcium stimulation and hepatic venous sampling (ASVS), the provisional diagnosis was a small insulinoma in the pancreatic body. The patient underwent subtotal distal pancreatectomy. However, histopathological and immunohistochemical examinations of the resected tissue showed hypertrophy of islets of Langerhans islands and beta cells around pancreatic ducts. The final diagnosis was adult-onset nesidioblastosis. Postoperatively, the patient continued to exhibit hyperinsulinemia and nighttime hypoglycemia. Octreotide, voglibose and diet therapies failed to improve the nocturnal hypoglycemia. However, treatment with diazoxide at a starting dose of 200 mg/day resulted in immediate amelioration of nocturnal hypoglycemia. This is the first Japanese adult case of nesidioblastosis treated successfully with diazoxide. This case report suggests that diazoxide may be effective for adult-onset nesidioblastosis in a manner similar to that described for pediatric cases.

Noninsulinoma pancreatogenous hypoglycemia syndrome: a rare case of adult-onset nesidioblastosis

The most common cause of hyperinsulinemic hypoglycemia in adults is insulinoma. Nesidioblastosis is a rare, but well-recognized disorder of persistent hyperinsulinemic hypoglycemia in infancy, but adult-onset nesidioblastosis associated with hyperinsulinemic hypoglycemia, termed noninsulinoma pancreatogenous hypoglycemic syndrome (NIPHS), has been reported. Here, we describe an extremely rare case of NIPHS in an elderly man. A 78-year-old man was admitted to our hospital due to hypoglycemic coma. During the previous 3 months, he noticed excessive sweating at midafternoon. His low fasting plasma glucose level (27 mg/dl) and high immunoreactive insulin level (11.1 muU/ml) were consistent with the possible presence of insulinoma. Localizing studies including computed tomography of the abdomen and celiac arteriography were negative, but selective arterial calcium infusion (SACI) test suggested the presence of insulinoma in the body and tail of the pancreas. Surgical exploration by palpation and intraoperative ultrasonography failed to detect any mass in the pancreas, and 60% distal pancreatectomy was performed. Postoperatively, his hypoglycemic episodes completely disappeared. Histological examination of the resected pancreas revealed diffuse islet cell hyperplasia consistent with a pathological diagnosis of nesidioblastosis. Thus, our case is a very rare case of NIPHS, or adult-onset nesidioblastosis, in which SACI test was proven to be a useful diagnostic tool for localization of the pancreatic lesion.

Nesidioblastosis - a Rare Cause of Hypoglycaemia in Adults

A case of suspected clinically hormonally active insulinoma in a 48-year-old woman is presented. Despite the lack of features, which might correspond to the insulinoma in radiological examinations, the patient was qualified for a distal subtotal pancreatectomy and then, due to persistent hyperinsulinism, for total pancreatectomy. The insulinoma was found neither in a palpable examination of the pancreas nor in the intraoperative ultrasonic examination. In a histopathological examination supplemented with immunohistochemical tests, nesidioblastosis - a rare cause of hypoglycaemia in adults - was diagnosed.

Nesidioblastosis: An Old Term and a New Understanding

Nesidioblastosis is a clinically, pathologically, and genetically heterogeneous disease. Differences between well described forms in neonates with persistent hyperinsulinemic hypoglycemia of infancy (PHHI) and rare forms in adults are described. Histopathologic criteria include hypertrophic islets occasionally showing beta cells with pleomorphic nuclei, ductuloinsular complexes, and neoformation of islets from ducts. These changes can be found as diffuse or focal forms of nesidioblastosis. Although most cases occur sporadically, several genetic defects ( SUR1, Kir6.2, GCK, and GLUD1 genes) have been described in neonates. In adults a higher rate of nesidioblastosis is observed in conjunction with multiple endocrine neoplasia type 1. The disease is diagnosed biochemically by a supervised fasting test in adults and in neonates by determining the glucose requirements to maintain normoglycemia, inappropriately high insulin and c-peptide levels, low free fatty acid and ketone body concentrations, glycemic response to glucagons, and the absence of ketonuria. If all highly selective noninvasive imaging techniques fail to identify a tumor, selective arterial calcium stimulation testing for gradient-guided surgery in adults and percutaneous transhepatic pancreatic venous sampling in neonates should be performed. a 95% pancreatectomy is necessary in neonates with a diffuse form of nesidioblastosis, whereas focal forms can be treated by partial pancreatectomy.

[Adult nesidioblastosis]

In adults, endogenous hyperinsulinemic hypoglycaemia is almost invariably due to insulinoma. The authors describe a 29 year old patient with repeated postprandial symptomatic hypoglycaemias and negative prolonged fast test. Distal pancreatectomy was performed, directed by positive arteriographic testing. Histological examination revealed pancreatic nesidioblastosis and no tumoral lesion. Distinct pathogenetic, clinical, diagnostic and therapeutic aspects of this rare disease in the adult are reviewed.