Determination of the Localization by Intra-arterial Calcium Stimulation in Insulinoma: A Case Report

Aims: Insulinoma, though a very rare disease, is the most common endocrine tumors of the pancreas. High serum insulin levels during hypoglycemic episodes are specific for the diagnosis. Where ultrasonography, tomography and other imaging modalities are not adequate for determination of the adenoma and its localization, hepatic venous sampling method with selective intra-arterial calcium stimulation becomes important in terms of determination of preoperative localization of adenoma and shortening surgery time.

Presentation of Case: A 38-year-old female patient investigated for weakness and low blood glucose was examined with a prediagnosis of insulinoma. Although clinical and laboratory results suggested insulinoma, no focus could be found by routine imaging methods. Hepatic venous sampling with selective intra-arterial calcium stimulation of the patient, who had pancreatic angiography, was performed. As a result of calcium stimulation performed from proximal splenic, mid splenic and gastroduodenal arteries, insulin and C-peptide levels in blood samples collected from hepatic vein were found to be high. The patient underwent an operation with intraoperative ultrasonography in which mass excision of the pancreas tail was performed. Pathologic examination revealed a neuroendocrine tumor showing synaptophysin, chromogranin and NSE (+) staining.

Discussion and Conclusion: Hepatic venous sampling with selective intra-arterial calcium stimulation in insulinomas is an extremely accurate and reliable method for the preoperative localization.