Lesson of the month 2: An unusual presentation of hyperinsulinaemic hypoglycaemia with possible underlying diagnosis of glucose-sensitive insulinoma or islet cell hyperplasia

Abstract

Postprandial hypoglycaemia can occur in islet cell hyperplasia and in reactive hypoglycaemia. Less commonly, it can occur with insulinoma. A case is described where the differential diagnosis was glucose-sensitive insulinoma or islet cell hyperplasia. Typical provocation was prolonged exertion or fasting followed by ingestion of sugary snacks resulting in hypoglycaemic seizures and collapse. Biochemistry and computerised tomography imaging were consistent with an insulinoma in the pancreatic tail, but this was not confirmed on endoscopic ultrasound. Selective intra-arterial calcium stimulation with hepatic venous sampling results suggested a diagnosis of islet cell hyperplasia. Ten years later, repeat imaging was consistent with a neuroendocrine tumour. Surgical resection has resulted in remission of symptoms. The patient will be monitored long term to ensure no recurrence.