Concomitant insulinoma and type 2 diabetes mellitus diagnoses: a case report

Insulinomas are rare neuroendocrine tumors of the pancreas. The annual incidence of the disease is approximately four per million people. The disease is more common in women, with a mean age of diagnosis of 47 years. Subjects with insulinomas typically present with neurologic symptoms (e.g. confusion, hunger, dizziness, and even hypoglycemic coma), as well as adrenergic symptoms due to catecholamine release (e.g. tachycardia and palpitations, tremor, and diaphoresis). The 72-h monitored fast is considered the gold standard for the diagnosis of insulinoma. The coexistence of type 2 diabetes mellitus (T2DM) and insulinoma has very rarely been reported in the literature. Herein, we present a case of simultaneous diagnoses of T2DM and an intrapancreatic insulinoma. Paradoxically, after surgical removal of the tumor and with the disappearance of the hypoglycemic episodes, we observed a significant improvement in glucose tolerance in the patient.