Secular trends in the presentation and management of functioning insulinoma at the Mayo Clinic, 1987-2007

J Clin Endocrinol Metab. 2009 Apr;94(4):1069-73. doi: 10.1210/jc.2008-2031. Epub 2009 Jan 13.


Objective: The objective of the study was to assess changes in the presentation and diagnostic and radiological evaluation of patients with surgically confirmed insulinoma at the Mayo Clinic 1987-2007.

Methods: A retrospective analysis of patients with insulinoma was conducted. Patients with prior gastric bypass were excluded.

Results: A total of 237 patients [135 women (57%)] were identified. Hypoglycemia was reported solely in the fasting state in 73%, the fasting and postprandial state in 21%, and exclusively postprandially in 6%. There was a predominance of men in the postprandial symptom group. Considering the period of study by quartile, outpatient evaluation increased from 35 to 83% and successful preoperative localization improved from 74 to 100% comparing the first to the fourth quartiles. Although the rates of localization by noninvasive techniques remained static at approximately 75%, the addition of invasive modalities has resulted in successful preoperative localization in all patients in the past 10 yr. The sensitivity and specificity of the established diagnostic criteria using insulin, C-peptide, proinsulin, beta-hydroxybutyrate, and glucose response to iv glucagon were greater than 90% and greater than 70%, respectively.

Conclusions: Although fasting hypoglycemia is characteristic of patients with insulinoma, postprandial symptoms have been reported with increasing, albeit low, frequency. Trends in the evaluation and preoperative management include a shift to outpatient diagnostic testing, an emphasis on successful preoperative localization to avoid blind pancreatic exploration, and a validation of the diagnostic criteria for hyperinsulinemic hypoglycemia.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Blood Glucose / metabolism*
  • Female
  • Humans
  • Hypoglycemia / etiology*
  • Inpatients / statistics & numerical data
  • Insulinoma / diagnosis
  • Insulinoma / pathology
  • Insulinoma / therapy*
  • Male
  • Medical Records
  • Middle Aged
  • Neoplasm Invasiveness
  • Outpatients / statistics & numerical data
  • Pancreatic Neoplasms / diagnosis
  • Pancreatic Neoplasms / pathology
  • Pancreatic Neoplasms / therapy*
  • Postprandial Period
  • Retrospective Studies
  • Young Adult


  • Blood Glucose