title: Combined use of calcium infusion localization and a minimally invasive surgical procedure in the management of insulinoma.
abstract: OBJECTIVE
  To review our experience with current diagnostic localization techniques and a minimally invasive laparoscopic surgical procedure in the management of insulinoma.
  
  
  METHODS
  We describe five patients with insulinoma, the results of diagnostic studies, and a proposed algorithm for management of this rare tumor.
  
  
  RESULTS
  Four female patients and one male patient (age range, 34 to 72 years) underwent supervised fasting (mean duration, 12 hours; range, 3 to 28 hours) to establish the diagnosis of insulinoma. These patients had glucose values that ranged from 38 to 41 mg/dL and associated serum insulin levels of 11.3 to 61 microU/mL. C-peptide values ranged from 3.4 to 11.5 ng/mL, and proinsulin levels (measured in four patients) were 32.9 to 82 pmol/L. These biochemical findings were diagnostic for insulin-mediated hypoglycemia, and the high proinsulin and C-peptide levels, in conjunction with negative results of serum measurements for sulfonylureas, excluded an exogenous source of insulin as the cause of hypoglycemia. Four of the five study patients had nondiagnostic results of noninvasive localization studies and underwent selective arterial injection of calcium with hepatic venous sampling to help localize the insulinomas within the pancreas. This procedure correctly localized the lesion in three patients and was associated with no complications. In all five patients, surgical resection of a solitary insulinoma (with use of laparoscopic procedures in four, one of which was converted to an open procedure) yielded resolution of the hypoglycemia.
  
  
  CONCLUSIONS
  The combination of calcium infusion localization and a minimally invasive surgical procedure is an efficient management approach in the diagnosis and treatment of insulinoma.
authors.affiliation: Division of Endocrinology and Molecular Medicine, Department of Internal Medicine, Chandler Medical Center, University of Kentucky, Lexington, 40536-0298, USA.
authors.forename: L Raymond
authors.initials: LR
authors.lastname: Reynolds
authors.forename: Adrian E
authors.initials: AE
authors.lastname: Park
authors.forename: Ralph E
authors.initials: RE
authors.lastname: Miller
authors.forename: Dennis G
authors.initials: DG
authors.lastname: Karounos
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D002096:C-Peptide / Q000097:blood; D002118:Calcium; D005260:Female; D006801:Humans; D007003:Hypoglycemia / Q000209:etiology / Q000628:therapy; D007328:Insulin / Q000097:blood; D007340:Insulinoma / Q000150:complications / Q000175:diagnosis* / Q000601:surgery*; D010535:Laparoscopy; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000150:complications / Q000175:diagnosis* / Q000601:surgery*; D011384:Proinsulin / Q000097:blood
chemical_list: D001786:Blood Glucose; D002096:C-Peptide; D007328:Insulin; D011384:Proinsulin; D002118:Calcium