Endocrine Abstracts

Introduction: Islet hyperplasia and nesidioblastosis are described in the non neoplastic pancreas of patients with gastrinoma. It is not definately established whether hypergastrinemia can influence these changes. Moreover, rarely insulinoma and gastrinoma occur in the same patient but cases of single tumours cosecreting both insulin and gastrin have been described. Otherwise, the syndrome of hyperinsulinemic hypoglycaemia with nesidioblastosis after Roux-en-Y gastric bypass has been previously reported and it is controversial.

Case report: We report on a 53-year-old woman suffering from multiple endocrine neoplasia type 1 (MEN1) confirmed by menin gene mutation analysis. MEN1 disease started with gastrinoma followed by primary hyperparathyroidism. Gastrinoma was located in gastrinoma triangle and presented gastric implants. She underwent tumor resection and a Roux-en-Y gastrectomy. Of 17 months later she began with symptoms of neuroglycopenia owing to endogenous hyperinsulinemia. Suspecting multiple microinsulinomas, a subtotal pancreatectomy was performed. Histopathologic examination revealed nesidioblastosis and several microadenomas. None of them expressed gastrin nor insulin but they expressed glucagon.

Conclusions: This case illustrates a rare cause of hypoglyacemia in a patient with gastrinoma. Although different causes can produce hypoglycaemia in these patients, in our case, the possibility of it being a cosecretor tumor or a neosidioblastosis secondary to hypergastrinemia is unlikely since there were no signs of persistant disease by the time hypoglycaemia started. However, it could be related to nesidioblastosis after Roux-en-Y gastrectomy, as it has been reported after bariatric surgery.