A rare case of focal nesidioblastosis causing adult-onset hypoglycemia.

Nesidioblastosis is a major cause of persistent hyperinsulinemic hypoglycemia of infancy and is caused by hypertrophy of the pancreatic endocrine islands. The disease can be categorized histologically into diffuse and focal forms. The condition rarely occurs in adults and only one adult case of suspected, but not histologically confirmed, focal nesidioblastosis has been reported. The present study describes the case of a 62-year-old man suffering from symptomatic hypoglycemia for 3 years and exhibiting a nodule in the pancreatic tail. Pathological evaluation following surgical enucleation of the pancreatic body and tail revealed focal nesidioblastosis. The hypoglycemic symptoms of the patient disappeared postoperatively. To the best of our knowledge, this is the first histologically-confirmed case of focal adult nesidioblastosis, suggesting that the possibility of nesidioblastosis should be taken into account in adult patients with persistent hypoglycemia.