Nesidioblastosis as the cause of hyperinsulinaemic hypoglycaemia in an adult is rare. We report here an additional case of nesidioblastosis, which resulted in fatal hyperinsulinaemic hypoglycaemia in a 72-year-old woman with an underlying myelodysplastic syndrome. The diagnosis of nesidioblastosis was established only after post-mortem examination with a careful exclusion of minute insulinoma. To our surprise, the renal pathology disclosed typical diabetic nodular glomerulosclerosis in the same patient who had no previous history of diabetes mellitus (DM). Nesidioblastosis has been reported to cause 'reversal' of Type 1 DM and insulinoma causing 'reversal' of Type 2 disease. We therefore hypothesize that our patient might have had an undiagnosed DM in the past, which resulted in the typical diabetic nodular glomerulosclerosis. The nesidioblastosis caused a 'reversal' of DM and even the ultimate development of hyperinsulinaemic hypoglycaemia.
