Adult-onset diffuse nesidioblastosis causing hypoglycemia.

We report the case of a 32-year-old male with adult-onset diffuse nesidioblastosis causing hypoglycemia. Under the tentative diagnosis of insulinoma, localization procedures were carried out but no tumor was found. The presence of an insulinoma in the tail of the pancreas was suggested by selective intra-arterial calcium stimulation with hepatic venous sampling (ASVS). A distal pancreatectomy was performed under the assumed diagnosis of insulinoma in the tail based upon the ASVS. Diffuse nesidioblastosis was diagnosed by histopathological evaluation. During the post-operative course, the patient's glucose and insulin levels were well controlled and uneventful without any medications or insulin for 7 months.