| A form of functioning pancreatic neuroendocrine tumor characterized most commonly by a solitary, small pancreatic lesion that causes hyperinsulinemic hypoglycemia. Insulinoma can present at any age but the median age of diagnosis is in the fifth decade of life. Insulinoma is malignant in only 7-10% of cases and the most common sites of metastasis are the liver and lymph nodes. The etiology is unknown in most sporadic cases but somatic YY1 (14q32.2) variants are associated with insulinoma in some cases. Insulinoma originates in the islet beta cells that are equally distributed throughout the pancreas. When functioning, the tumor manifests with hypersecretion of insulin and consequently causes hypoglycemia. With the exception of insulinoma in MEN1, insulinoma is not hereditary. |
