Special diagnostic and therapeutic aspects of insulinomas

Insulinomas are rare tumors and account for 90% of all endocrine pancreatic tumors. They typically present as a solitary tumor, but may occur in multiple sites (e.g. multiple endocrine neoplasia type I) or as a malignant disease in 10% of cases and rarely as nesidioblastosis or islet cell adenomatosis. Neuroglucopenic symptoms lead to the diagnosis; inadequate high insulin and C-peptide secretion with hypoglycemia in the fasting test confirm the diagnosis. Preoperative localization is not necessary prior to the first operation. The standard operation is enucleation or, depending on size and location, resection. The treatment of multiple tumors and islet cell hyperplasia with a high risk of recurrence is problematic. Subtotal resection plus enucleation seems to be better than selective tumor resection. In malignant insulinomas, mostly presenting with liver metastases, aggressive surgical therapy with hepatectomy and debulking, chemoembolization and systemic chemotherapy are the modalities of choice.