Occurrence of giant focal forms of congenital hyperinsulinism with incorrect visualization by (18) F DOPA-PET/CT scanning

18F-6-Fluoro-l-Dopa PET/CT Imaging of Congenital Hyperinsulinism

Congenital hyperinsulinism is characterized by persistent hypoglycemia due to inappropriate excess secretion of insulin resulting in hyperinsulinemic hypoglycemia. The clinical course varies from mild to severe, with a significant risk for brain damage. Imaging plays a valuable role in the care of infants and children with severe hypoglycemia unresponsive to medical therapy. ¹⁸F-6-fluoro-l-dopa PET/CT is the method of choice for the detection and localization of a focal lesion of hyperinsulinism. Surgical resection of a focal lesion can lead to a cure with limited pancreatectomy. This article reviews the role of ¹⁸F-6-fluoro-l-dopa PET/CT in the management of this vulnerable population.

18-F-L 3,4-Dihydroxyphenylalanine PET/Computed Tomography in the Management of Congenital Hyperinsulinism

Congenital hyperinsulinism (HI) is the most common cause of persistent hypoglycemia in neonates and infants. Several genetic mutations have been identified and are associated with 2 distinct histopathologic forms of disease: diffuse and focal. Targeted clinical evaluation to distinguish medically treatable disease from disease requiring surgical management can prevent life-threatening complications. Detection and localization of a surgically curable focal lesion using PET imaging with 18-F-L 3,4-dihydroxyphenylalanine ([18F]-FDOPA) has become standard of care. This article provides guidelines for the selection of patients who can benefit from [18F]-FDOPA-PET/computed tomography and protocols and tips used to diagnose a focal lesion of HI.

Hyperinsulinemic hypoglycemia in children and adolescents: Recent advances in understanding of pathophysiology and management

Hyperinsulinemic hypoglycemia (HH) is characterized by unregulated insulin release, leading to persistently low blood glucose concentrations with lack of alternative fuels, which increases the risk of neurological damage in these patients. It is the most common cause of persistent and recurrent hypoglycemia in the neonatal period. HH may be primary, Congenital HH (CHH), when it is associated with variants in a number of genes implicated in pancreatic development and function. Alterations in fifteen genes have been recognized to date, being some of the most recently identified mutations in genes HK1, PGM1, PMM2, CACNA1D, FOXA2 and EIF2S3. Alternatively, HH can be secondary when associated with syndromes, intra-uterine growth restriction, maternal diabetes, birth asphyxia, following gastrointestinal surgery, amongst other causes. CHH can be histologically characterized into three groups: diffuse, focal or atypical. Diffuse and focal forms can be determined by scanning using fluorine-18 dihydroxyphenylalanine-positron emission tomography. Newer and improved isotopes are currently in development to provide increased diagnostic accuracy in identifying lesions and performing successful surgical resection with the ultimate aim of curing the condition. Rapid diagnostics and innovative methods of management, including a wider range of treatment options, have resulted in a reduction in co-morbidities associated with HH with improved quality of life and long-term outcomes. Potential future developments in the management of this condition as well as pathways to transition of the care of these highly vulnerable children into adulthood will also be discussed.

Case report: contradictory genetics and imaging in focal congenital hyperinsulinism reinforces the need for pancreatic biopsy

Background

Congenital Hyperinsulinism (CHI) is an important cause of severe hypoglycaemia in infancy due to excessive, dysregulated insulin secretion. In focal CHI, a localised lesion within the pancreas hypersecretes insulin and, importantly, hypoglycaemia resolution is possible through limited surgical resection of the lesion. Diagnosis of focal CHI is based on a crucial combination of compatible genetics and specialised imaging. Specifically, a focal lesion arises due to a paternal mutation in one of the ATP-sensitive potassium channel genes, KCNJ11 or ABCC8, in combination with post-zygotic loss of maternal heterozygosity within the affected pancreatic tissue. 6-[18F]Fluoro-L-3,4-dihydroxyphenylalanine (¹⁸F-DOPA) positron emission tomography (PET)/computed tomography (CT) imaging is used to detect and localise the lesion prior to surgery. However, its accuracy is imperfect and needs recognition in individual case management.

Case presentation

We report the case of an infant with hypoglycaemia due to CHI and a paternally inherited KCNJ11 mutation, c.286G > A (p.Ala96Thr), leading to a high probability of focal CHI. However,¹⁸F-DOPA PET/CT scanning demonstrated diffuse uptake and failed to conclusively identify a focal lesion. Due to unresponsiveness to medical therapy and ongoing significant hypoglycaemia, surgery was undertaken and a small 4.9 × 1.7 mm focal lesion was discovered at the pancreatic neck. This is the second case where this particular KCNJ11 mutation has been incorrectly associated with diffuse ¹⁸F-DOPA uptake, in contrast to the correct diagnosis of focal CHI confirmed by pancreatic biopsy.

Conclusions

Identifying discrepancies between genetic and imaging investigations is crucial as this may negatively impact upon the diagnosis and surgical treatment of focal CHI. This case highlights the need for pancreatic biopsy when a strong suspicion of focal CHI is present even if ¹⁸F-DOPA imaging fails to demonstrate a discrete lesion.

Clinical Diversity in Focal Congenital Hyperinsulinism in Infancy Correlates With Histological Heterogeneity of Islet Cell Lesions

Background: Congenital Hyperinsulinism (CHI) is an important cause of severe and persistent hypoglycaemia in infancy and childhood. The focal form (CHI-F) of CHI can be potentially cured by pancreatic lesionectomy. While diagnostic characteristics of CHI-F pancreatic histopathology are well-recognized, correlation with clinical phenotype has not been established. Aims: We aimed to correlate the diversity in clinical profiles of patients with islet cell organization in CHI-F pancreatic tissue. Methods: Clinical datasets were obtained from 25 patients with CHI-F due to ABCC8/KCNJ11 mutations. ¹⁸F-DOPA PET-CT was used to localize focal lesions prior to surgery. Immunohistochemistry was used to support protein expression studies. Results: In 28% (n = 7) of patient tissues focal lesions were amorphous and projected into adjoining normal pancreatic tissue without clear delineation from normal tissue. In these cases, severe hypoglycaemia was detected within, on average, 2.8 ± 0.8 (range 1-7) days following birth. By contrast, in 72% (n = 18) of tissues focal lesions were encapsulated within a defined matrix capsule. In this group, the onset of severe hypoglycaemia was generally delayed; on average 46.6 ± 14.3 (range 1-180) days following birth. For patients with encapsulated lesions and later-onset hypoglycaemia, we found that surgical procedures were curative and less complex. Conclusion: CHI-F is associated with heterogeneity in the organization of focal lesions, which correlates well with clinical presentation and surgical outcomes.

Congenital Hyperinsulinism: Diagnosis and Treatment Update

Pancreatic β-cells are finely tuned to secrete insulin so that plasma glucose levels are maintained within a narrow physiological range (3.5-5.5 mmol/L). Hyperinsulinaemic hypoglycaemia (HH) is the inappropriate secretion of insulin in the presence of low plasma glucose levels and leads to severe and persistent hypoglycaemia in neonates and children. Mutations in 12 different key genes (ABCC8, KCNJ11, GLUD1, GCK, HADH, SLC16A1, UCP2, HNF4A, HNF1A, HK1, PGM1 and PMM2) that are involved in the regulation of insulin secretion from pancreatic β-cells have been described to be responsible for the underlying molecular mechanisms leading to congenital HH. In HH due to the inhibitory effect of insulin on lipolysis and ketogenesis there is suppressed ketone body formation in the presence of hypoglycaemia thus leading to increased risk of hypoglycaemic brain injury. Therefore, a prompt diagnosis and immediate management of HH is essential to avoid hypoglycaemic brain injury and long-term neurological complications in children. Advances in molecular genetics, imaging techniques (18F-DOPA positron emission tomography/computed tomography scanning), medical therapy and surgical advances (laparoscopic and open pancreatectomy) have changed the management and improved the outcome of patients with HH. This review article provides an overview to the background, clinical presentation, diagnosis, molecular genetics and therapy in children with different forms of HH.

18F-DOPA PET/CT and 68Ga-DOTANOC PET/CT scans as diagnostic tools in focal congenital hyperinsulinism: a blinded evaluation

Purpose

Focal congenital hyperinsulinism (CHI) is curable by surgery, which is why identification of the focal lesion is crucial. We aimed to determine the use of 18F–fluoro-dihydroxyphenylalanine (18F-DOPA) PET/CT vs. 68Ga-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic-acid-1-Nal3-octreotide (68Ga-DOTANOC) PET/CT as diagnostic tools in focal CHI.

Methods

PET/CT scans of children with CHI admitted to Odense University Hospital between August 2005 and June 2016 were retrospectively evaluated visually and by their maximal standardized uptake values (SUV_max) by two independent examiners, blinded for clinical, surgical and pathological data. Pancreatic histology was used as the gold standard. For patients without surgery, the genetic profile served as the gold standard.

Results

Fifty-five CHI patients were examined by PET/CT (18F-DOPA n = 53, 68Ga-DOTANOC n = 18). Surgery was performed in 34 patients, no surgery in 21 patients. Fifty-one patients had a classifiable outcome, either by histology (n = 33, 22 focal lesions, 11 non-focal) or by genetics (n = 18, all non-focal). The predictive performance of 18F-DOPA PET/CT to identify focal CHI was identical by visual- and cut-off-based evaluation: sensitivity (95% CI) of 1 (0.85–1); specificity of 0.96 (0.82–0.99). The optimal 18F-DOPA PET SUV_max ratio cut-off was 1.44 and the optimal 68Ga-DOTANOC PET SUV_max cut-off was 6.77 g/ml. The area under the receiver operating curve was 0.98 (0.93–1) for 18F-DOPA PET vs. 0.71 (0.43–0.95) for 68Ga-DOTANOC PET (p < 0.03). In patients subjected to surgery, localization of the focal lesion was correct in 91%, and 100%, by 18F-DOPA PET/CT and 68Ga-DOTANOC PET/CT, respectively.

Conclusion

18F-DOPA PET/CT was excellent in predicting focal CHI and superior compared to 68Ga-DOTANOC PET/CT. Further use of 68GA-DOTANOC PET/CT in predicting focal CHI is discouraged.

Electronic supplementary material

The online version of this article (10.1007/s00259-017-3867-1) contains supplementary material, which is available to authorized users.

Clinical practice guidelines for congenital hyperinsulinism

Congenital hyperinsulinism is a rare condition, and following recent advances in diagnosis and treatment, it was considered necessary to formulate evidence-based clinical practice guidelines reflecting the most recent progress, to guide the practice of neonatologists, pediatric endocrinologists, general pediatricians, and pediatric surgeons. These guidelines cover a range of aspects, including general features of congenital hyperinsulinism, diagnostic criteria and tools for diagnosis, first- and second-line medical treatment, criteria for and details of surgical treatment, and future perspectives. These guidelines were generated as a collaborative effort between The Japanese Society for Pediatric Endocrinology and The Japanese Society of Pediatric Surgeons, and followed the official procedures of guideline generation to identify important clinical questions, perform a systematic literature review (April 2016), assess the evidence level of each paper, formulate the guidelines, and obtain public comments.

Enhanced Islet Cell Nucleomegaly Defines Diffuse Congenital Hyperinsulinism in Infancy but Not Other Forms of the Disease

OBJECTIVES

To quantify islet cell nucleomegaly in controls and tissues obtained from patients with congenital hyperinsulinism in infancy (CHI) and to examine the association of nucleomegaly with proliferation.

METHODS

High-content analysis of histologic sections and serial block-face scanning electron microscopy were used to quantify nucleomegaly.

RESULTS

Enlarged islet cell nuclear areas were 4.3-fold larger than unaffected nuclei, and the mean nuclear volume increased to approximately threefold. Nucleomegaly was a normal feature of pediatric islets and detected in the normal regions of the pancreas from patients with focal CHI. The incidence of nucleomegaly was highest in diffuse CHI (CHI-D), with more than 45% of islets containing two or more affected cells. While in CHI-D nucleomegaly was negatively correlated with cell proliferation, in all other cases, there was a positive correlation.

CONCLUSIONS

Increased incidence of nucleomegaly is pathognomonic for CHI-D, but these cells are nonproliferative, suggesting a novel role in the pathobiology of this condition.