Endocrine Abstracts

Nesidioblastosis is defined as a diffuse proliferation of primitive pancreatic islet cells budding from ductal epithelium. This condition can cause hypoglycaemia in infants as a result of mutations in the sulfonylurea receptor or in the anatomically linked potassium channel. In adults, this disease occurs independently from these genetic mutations.

Case report: A 41-year-old male was referred to our center via emergency room with suspicion of an insulinoma after an episode of loss of consciousness with a glycemia (G) of 24 mg/dl. Further questioning revealed three similar episodes in 2012. At admission: altered general status with retrograde amnesia, dry skin and mucous membrane and deep tenderness in the epigastrum, pulse 65 b/min. The 72 h fast was stopped for symptomatic hypoglycaemia with high insulinaemia. Imaging studies were normal excepting endoscopic ultrasound which revealed a pseudolobular aspect in the pancreas tail and body. The patient was guided to a surgical clinic with dietetic recommendation and phenytoin 200 mg/day for insulinoma localization and surgical treatment. His was admitted into the surgical clinic after 3 weeks from the previous hospitalization with only two moderate hypoglycaemic episode under phenytoin treatment. The short octreotide test was interrupted due to symptomatic hypoglycaemia confirming the lack of tumour somatostatinoma receptors. Exploratory laparotomy was performed with intraoperative ultrasonography which exhibited two tumors in the pancreas tail and body. A subtotal spleno-pancreatectomy was performed. Microscopic view was consistent with nesidioblastosis and no tumour was found. The patient remains euglycaemic 10 months post-operatively.

Discussions: Nesidioblastosis is a rare cause of adult hypoglycaemia. Pre-operative differentiation from insulinoma is difficult, but mandatory when imaging studies are negative. New diagnostic tools like ¹⁸F-DOPA PET scan or selective arterial calcium stimulation with hepatic venous sampling (unavailable in our country) could help establishing the diagnosis.