Insulinomas are uncommon tumors, and in patients with diabetes mellitus they are extremely rare. We describe a patient with type 1 diabetes who developed malignant insulinoma. When hypoglycemic episodes persist in a patient with diabetes and treatment-induced and other causes of hypoglycemia have been ruled out, an insulin-producing tumor should be considered.
Keywords: Chromogranin; diabetes; hypoglycemia; insulin secretion; insulinoma.