Insulinoma in a Patient With NIDDM

L A Kane; C S Grant; T B Nippoldt; F J Service

doi:10.2337/diacare.16.9.1298

Short Reports

Insulinoma in a Patient With NIDDM

L A Kane, MD,
C S Grant, MD,
T B Nippoldt, MD and
F J Service, MD

Division of Endocrinology and Metabolism, Department of Internal Medicine and Department of Surgery, Mayo Medical School and Mayo Clinic Rochester, Minnesota

Address correspondence and reprint requests to F. J. Service, MD, Mayo Clinic, 200 First Street, SW, Rochester, MN 55905.

Diabetes Care 1993 Sep; 16(9): 1298-1300. https://doi.org/10.2337/diacare.16.9.1298

Abstract

Objective— To confirm insulinoma as the cause of hypoglycemia in a patient with NIDDM and determine the frequency of the co-occurrence of these two conditions.

Research Design and Methods— The patient underwent an in-hospital prolonged fast (≤72 h), according to standard protocol, and an ultrasound examination of the pancreas. All cases of histologically confirmed insulinoma at this institution over the period of 1927–1992 were reviewed to determine the prevalence of pre-existent diabetes mellitus.

Results— After 10 h of fasting, plasma glucose was low (1.89 mM); plasma insulin (258 pM) and C-peptide (1.39 nM) were elevated in the absence of sulfonylurea in the plasma. An insulinoma detected by ultrasonography was removed surgically with subsequent reoccurrence of insulin-requiring diabetes. Among 313 cases of insulinoma confirmed at this institution, this patient is the only one with pre-existent diabetes mellitus.

Conclusions— Insulinoma occurs extraordinarily rarely in patients with pre-existing NIDDM.