Applying Intraoperative Insulin Level Monitoring for Tumor Removal in a Patient With Recurrent Pancreatic Multiple Insulinomas

Abstract

Pancreatic multiple insulinoma is a very rare disease. Surgical treatment is challenging, as the localization of the tumor lesion is rather complicated. We report a case of a 47-year-old woman with recurrent hypoglycemia after distal pancreatectomy for her insulinoma. Multiple insulinomas were found in the first pathology report. Follow-up abdominal computed tomography (CT) did not show any lesion. One suspected tumor at the pancreatic head was found on abdominal magnetic resonance imaging (MRI), whereas the result of the intra-arterial calcium stimulation (IACS) test suggested diffuse β-cell hyperfunction. Using a quick insulin assay, intraoperative blood insulin monitoring demonstrated a decrease in insulin level after the removal of the main tumor during the second surgery. A 75% subtotal pancreatectomy was also performed, and the patient is well with no hypoglycemic attacks or diabetes reported 15 months after the second operation. In addition to intraoperative sonography and manual palpation, intraoperative insulin quick assay may be another useful guide during surgery. Most insulinomas are small, solitary, benign, and intrapancreatic. Multiple insulinomas are common in multiple endocrine neoplasia type 1 (MEN-1), which accounts for approximately 10% of all patients with insulinoma.1 For recurrent insulinoma, preoperative localization and definite complete resection during surgery are challenging issues. There are many available techniques for localization of the insulinoma, including transabdominal ultrasonography, CT, MRI, endoscopic ultrasonography (EUS), angiography, IACS, somatostatin receptor scintigraphy (SRS), positron emission tomography (PET), intra-operative ultrasonography (IOUS) and intra-operative palpation. We present a case that underwent a second subtotal pancreatectomy for recurrent hypoglycemia due to multiple insulinomas. The surgery was performed successfully using intraoperative insulin level monitoring by a new quick insulin assay (an electrochemiluminescent immunoassay).