Secular trends in the presentation and management of functioning insulinoma at the Mayo Clinic, 1987-2007.
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.
Placzkowski
Kimberly A
KA
Department of Medicine, Division of Endocrinology and Metabolism, Mayo Clinic, Rochester, Minnesota 55905, USA.
Vella
Adrian
A
Thompson
Geoffrey B
GB
Grant
Clive S
CS
Reading
Carl C
CC
Charboneau
J William
JW
Andrews
James C
JC
Lloyd
Ricardo V
RV
Service
F John
FJ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000378:metabolism*; D005260:Female; D006801:Humans; D007003:Hypoglycemia / Q000209:etiology*; D007297:Inpatients / Q000706:statistics & numerical data; D007340:Insulinoma / Q000175:diagnosis / Q000473:pathology / Q000628:therapy*; D008297:Male; D008499:Medical Records; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D010045:Outpatients / Q000706:statistics & numerical data; D010190:Pancreatic Neoplasms / Q000175:diagnosis / Q000473:pathology / Q000628:therapy*; D019518:Postprandial Period; D012189:Retrospective Studies; D055815:Young Adult
D001786:Blood Glucose