Summary

A 42-year-old woman presented to her general practitioner (GP) with episodes of feeling ‘shaky’ exacerbated by physical exercise and prolonged fast. She was previously diagnosed with an insulinoma in 2006 (serum glucose 1.6 mmol/l, serum insulin 3.1 mIU/l and serum C peptide <165 pmol/l). CT abdomen/transabdominal ultrasound revealed a 1 cm insulinoma in the uncinate process of the pancreas and the patient later underwent pancreatic enucleation in 2006. Postpancreatic enucleation, 72 h fast was negative. The patient remained asymptomatic postoperation and re-presented to a locum GP 6 years later with initial symptoms. She was reviewed during her annual follow-up and, owing to concerns relating to her background, she was admitted to the specialist endocrine department for further investigations. A 72 h fast was positive for hypoglycaemia with serum glucose level 1.8 mmol/l, serum insulin 8.6 mIU/l and serum C peptide 443 pmol/l.