Endocrine Abstracts

We present a 65-year-old lady initially diagnosed and treated for epilepsy who was subsequently referred 10 years later for the investigation of underlying spontaneous hypoglycaemia. Laboratory plasma glucose concentrations of 2.0 and 1.7 mmol/l were recorded prior to referral and subsequently a fasting challenge provoked hypoglycaemia associated with a plasma glucose of 0.8 mmol/l, C-peptide 371 pmol/l (NR 120–600) and insulin 7.4 mU/l (NR 0–10). CT and MRI imaging of her pancreas revealed a 10 mm vividly enhancing oval nodule within the parenchyma of the mid body of the pancreas consistent with an insulinoma.

Initial treatment with diazoxide was not tolerated due to nausea and she was converted to lanreotide injections (60 mg every 28 days). Her hypoglycaemic episodes resolved and phenytoin was tailed off with resolution of her ‘epilepsy’. Surgical resection of the insulinoma was advised but the patient did not want to proceed in view of her successful response to lanreotide and fear of surgery and its complications. She has now remained on lanreotide for over 4 years without side effects and is asymptomatic. She maintains her desire to avoid surgical resection.

Insulinomas are β-cell tumours of the pancreas, which can present with hypoglycaemia and are often misdiagnosed. Somatostatin analogues are known to be an effective treatment for insulinomas and have been used as a short-term measure. However, whilst they are an established long-term treatment of carcinoid tumours (having been used in individual patients for over 10 years), this case demonstrates that long-term use of somatostatin analogues may also be an effective treatment for insulinomas in those individuals not undertaking surgical resection.