Insulinoma

Insulinoma remains a very rare tumor, and the first challenge to making the diagnosis is to consider it. Although these tumors are typically benign, they can cause severe and often bizarre symptoms. The diagnosis is established with biochemical confirmation of hypoglycemia and endogenous hyperinsulinemia after fasting, and is distinguished from the postprandial hyperinsulinemic hypoglycemia of Noninsulinoma Pancreatogenous Hyperinsulinemia Syndrome (NIPHS). Operative removal of the tumor is the mainstay of treatment, but is predicated on precise preoperative localization. Multiple imaging options are available, including: transabdominal ultrasound, computed tomography, endoscopic ultrasound (EUS), angiography with intraarterial calcium stimulation testing, and intraoperative ultrasound (IOUS). Patients with MEN-1 syndrome virtually always have multiple pancreatic neuroendocrine tumors, and evaluation and treatment of these patients is different than for sporadic disease. Surgical excision of the disease is the only cure; in the rare case of malignant disease, an aggressive surgical and multimodal approach is recommended, even for palliation of hypoglycemia.