Nesidioblastosis in an elderly patient.

We report an 84-year-old woman with hypoglycaemia and hyperinsulinaemia caused by diffuse nesidioblastosis. This is the oldest case of nesidioblastosis so far recorded. The case illustrates some of the difficulties in diagnosing inappropriate hyperinsulinaemia and the benefits of surgery, even in old age. Hypoglycaemia should be considered in patients with variable mental function.