Victor Kalff1, Amir Iravani1,2, Timothy Ackhurst1,2, David A Pattison3, Peter Eu1, Michael S Hofman1,2, Rodney J Hicks1,4,2. 1. Centre for Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne, Australia. 2. The Sir Peter MacCallum Department of Oncology, Melbourne University, Melbourne, Australia. 3. Department of Nuclear Medicine and Specialised PET Services, Royal Brisbane & Women's Hospital, Brisbane, Australia. 4. Neuroendocrine Service, Peter MacCallum Cancer Centre, Melbourne, Australia.
Abstract
BACKGROUND: Because management is very different, it is important to differentiate between small focal insulinomas and diffuse pancreatic dysplasia (nesidioblastosis) in patients with confirmed endogenous hyperinsulinaemic hypoglycaemia (EHH). Most insulinomas highly express Glucagon Like Peptide-1 receptors enabling PET/CT imaging with its radiolabelled analogue; 68 Ga-DOTA-exendin-4 (Exendin). AIM: To determine (a) the utility of Exendin in EHH patients in a clinical setting; (b) whether degree of Exendin uptake differentiates non-insulinoma pancreatogenous hypoglycaemia syndrome (NIPHS) from post gastric bypass hypoglycaemia (PGBH). METHODS: This retrospective study reviewed the clinical, biochemistry and prior imaging findings in confirmed EHH patients referred for Exendin. Accuracy of Exendin was based on surgical findings and treatment outcomes. Finally, average Exendin uptake (SUVmax) of 5 PGBH studies was compared with the SUVmax of a key NIPHS case report.1 RESULTS: 20/25 consecutive patients had confirmed EHH. Exendin located insulinomas in 8/9 patients enabling successful surgical excision with rapid and durable cure. Exendin correctly identified diffuse nesidioblastosis in 2/3 cases requiring partial pancreatectomy for hypoglycaemia control. All 3 relapsed within 1.7 years with 1 needing completion pancreatectomy. Establishing the cause in the remainder relied on other investigations, clinical correlation and response to empirical treatment. Finally, Exendin SUVmax could not distinguish between NIPHS and PGBH. CONCLUSION: In EHH patients, Exendin accurately identifies the site of insulinoma and thereby differentiates it from nesidioblastosis but negative findings should not be ignored. Exendin is unlikely to differentiate between normal pancreatic uptake, NIPHS and PGBH. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
BACKGROUND: Because management is very different, it is important to differentiate between small focal insulinomas and diffuse pancreatic dysplasia (nesidioblastosis) in patients with confirmed endogenous hyperinsulinaemic hypoglycaemia (EHH). Most insulinomas highly express Glucagon Like Peptide-1 receptors enabling PET/CT imaging with its radiolabelled analogue; 68 Ga-DOTA-exendin-4 (Exendin). AIM: To determine (a) the utility of Exendin in EHH patients in a clinical setting; (b) whether degree of Exendin uptake differentiates non-insulinoma pancreatogenous hypoglycaemia syndrome (NIPHS) from post gastric bypass hypoglycaemia (PGBH). METHODS: This retrospective study reviewed the clinical, biochemistry and prior imaging findings in confirmed EHH patients referred for Exendin. Accuracy of Exendin was based on surgical findings and treatment outcomes. Finally, average Exendin uptake (SUVmax) of 5 PGBH studies was compared with the SUVmax of a key NIPHS case report.1 RESULTS: 20/25 consecutive patients had confirmed EHH. Exendin located insulinomas in 8/9 patients enabling successful surgical excision with rapid and durable cure. Exendin correctly identified diffuse nesidioblastosis in 2/3 cases requiring partial pancreatectomy for hypoglycaemia control. All 3 relapsed within 1.7 years with 1 needing completion pancreatectomy. Establishing the cause in the remainder relied on other investigations, clinical correlation and response to empirical treatment. Finally, Exendin SUVmax could not distinguish between NIPHS and PGBH. CONCLUSION: In EHH patients, Exendin accurately identifies the site of insulinoma and thereby differentiates it from nesidioblastosis but negative findings should not be ignored. Exendin is unlikely to differentiate between normal pancreatic uptake, NIPHS and PGBH. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
Authors: Jess C Hercus; Pouneh Pasha; Sadiq Al Lawati; Peter Kim; Andre Mattman; Douglas Webber; David M Thompson Journal: Case Rep Endocrinol Date: 2022-10-07