An insulinoma presenting as hypoglycaemia associated with exercise stress testing.

A 68-year-old man presented to the accident and emergency department with a history of central chest pain associated with exertion. He was admitted for assessment and when an acute coronary syndrome was excluded, he underwent exercise stress testing. His exercise stress testing was discontinued due to lightheadedness. His capillary glucose was checked and it showed hypoglycaemia (2.2 mmol/l). In light of this, a 72 h supervised fast was performed and it became positive within 24 h with low plasma glucose, inappropriately high insulin and C peptide levels. Sulfonylurea screen was negative. CT, MRI and endoscopic ultrasound revealed a 2 cm pancreatic tail insulinoma. He underwent successful surgical enucleation of this lesion.