title: Intraoperative ultrasound and preoperative localization detects all occult insulinomas; discussion 1025-6.
abstract: OBJECTIVE
  Preoperative invasive localization procedures with intraoperative ultrasound (IOUS) can result in successful surgical treatment of occult insulinomas when noninvasive imaging study results are equivocal or negative.
  
  
  METHODS
  Prospective study.
  
  
  METHODS
  Tertiary care university hospital.
  
  
  METHODS
  Thirty-seven consecutive patients with a biochemical diagnosis of insulinoma without multiple endocrine neoplasia (MEN).
  
  
  METHODS
  All patients underwent portal venous sampling (PVS) (n = 22) or calcium angiogram (n = 15) followed by surgery with palpation and IOUS (n = 37).
  
  
  METHODS
  Portal venous sampling, calcium angiogram, palpation, and IOUS were compared for accurate localization of insulinoma.
  
  
  RESULTS
  All patients were cured of hypoglycemia after surgery. Portal venous sampling correctly localized tumors in 17 (77%) of 22 patients. Calcium angiogram was correct in 13 (87%) of 15 patients. Palpation identified 24 (65%) of 37 tumors, and IOUS found 35 (95%) of 37 tumors. The 2 tumors missed by IOUS were located in the tail of the pancreas and were resected based on regional localization alone.
  
  
  CONCLUSIONS
  Intraoperative ultrasound is the single best localization study, but it will miss some tumors that regional localization can identify. Combining both modalities allowed surgical cure of all insulinomas in our study. Therefore, we recommend both IOUS and regional localization for insulinoma when preoperative imaging studies are equivocal.
authors.affiliation: Department of Surgery, San Francisco Veterans Affairs Medical Center, Surgical Service (112), 4150 Clement St, San Francisco, CA 94121, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Hiramoto
authors.forename: V A
authors.initials: VA
authors.lastname: Feldstein
authors.forename: J M
authors.initials: JM
authors.lastname: LaBerge
authors.forename: J A
authors.initials: JA
authors.lastname: Norton
mesh_terms: D000328:Adult; D000368:Aged; D000792:Angiography; D002125:Calcium Gluconate; D005260:Female; D006503:Hepatic Veins; D006801:Humans; D007328:Insulin / Q000097:blood / Q000378:metabolism; D000078790:Insulin Secretion; D007340:Insulinoma / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000601:surgery; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D010179:Pancreas / Q000098:blood supply; D010190:Pancreatic Neoplasms / Q000175:diagnosis / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000601:surgery; D011169:Portal Vein; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014463:Ultrasonography
chemical_list: D007328:Insulin; D002125:Calcium Gluconate