Diagnosis and Localization of Insulinoma After Negative Laparotomy by Hyperinsulinemic, Hypoglycemic Clamp and Intra-Arterial Calcium Stimulation

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Abstract
The Review of Diabetic Studies,2004,1,1,42-46.
Published:May 2004
Type:Case Report
Authors:
Author(s) affiliations:

Robert A. Ritzel1, Berend Isermann1, Tobias Schilling1, Hanns-Peter Knaebel2, Markus W. Büchler2, Peter P. Nawroth1

1Department of Medicine I, University of Heidelberg, Im Neuenheimer Feld 410, 69120 Heidelberg, Germany.

2Department of General Surgery, University of Heidelberg, Im Neuenheimer Feld 110, 69120 Heidelberg, Germany.

Abstract:

A 40-year-old woman with recurrent episodes of hypoglycemia was referred because of suspected insulinoma. Prolonged fasting was discontinued after 24 h due to symptomatic hypoglycemia (29 mg/dl, glucose/insulin-ratio 0.34). Magnetic resonance tomography showed a small 0.3 cm lesion in the body of the pancreas. During subsequent surgery a pancreatic tumor could not be detected, neither by manual palpation nor intraoperative ultrasonography. A hyperinsulinemic, sequentially eu- and hypoglycemic clamp confirmed the biochemical diagnosis of endogenous hyperinsulinemia and intra-arterial calcium stimulation localized calcium responsive tissue in the feeding distribution of the superior mesenteric artery. An octreotide scan was negative. During relaparotomy, six weeks after the initial surgery, the pancreatic body and tail were resected and a ~1 cm nonmalignant insulinoma was found. Although the use of highly sensitive, and more sophisticated and expensive methods for the diagnosis and localization of insulinomas are not generally suggested, we recommend application of intra-arterial calcium stimulation if the tumor is not detected using conventional diagnostic procedures.