INSULINOMA AND ISLET-CELL HYPERPLASIA - VALUE OF THE CALCIUM INTRAARTERIAL STIMULATION TEST WHEN FINDINGS OF OTHER PREOPERATIVE STUDIES ARENEGATIVE

PURPOSE: To evaluate the efficacy of the intraarterial calcium-test in localizing sources of hyperinsulinism that remain undetectable at pre operative morphologic studies. MATERIALS AND METHODS: Twenty-four pati ents with clinically proved endogenous hyperinsulinism due to tumorous insulin production were prospectively enrolled. They underwent ultras ound (US), computed tomography, magnetic resonance imaging, endoscopic US, abdominal arteriography, and a calcium test, in which insulin con centrations, were measured in hepatic venous blood after selective int raarterial calcium stimulation. The results of the calcium test in sev en patients (five women, two men; age range, 30-66 years; mean age, 47 years) with negative findings of morphologic studies are described. R ESULTS: Six solitary insulinomas (mean diameter, 0.73 cm) and one nodu lar hyperplasia were diagnosed after surgery. In all seven cases, calc ium test findings allowed accurate localization of the pathologic sour ce of insulin secretion. In three of these seven cases, results of art erial calcium simulation with hepatic venous sampling (ASVS) affected intraoperative management. An increase in insulin concentration after stimulation in the hepatic artery was hot observed, making hepatic met astases unlikely. CONCLUSION: ASVS, which is procedurally simpler than transhepatic pancreatic venous sampling, is effective for localizing sources of hyperinsulinism not detected with preoperative morphologic studies.