Localization of Multiple Pancreatic Insulinoma by Intra-arterial Calcium Stimulation with Hepatic Venous Sampling and Intra-operative Ultrasound Imaging: a Case Report

Insulinoma is a rare neuroendocrine tumor with an incidence of approximately 4 per 5 million population. They are typically sporadic, solitary and less than 2 cm in diameter. Despite the in-troduction of sophisticated cross-imaging tech-niques such as CT scan, MRI and ultrasound, lo-calization of insulinomas, especially those smaller than 2 cm remains a problem; for this, one can localize insulinoma by stimulating re-lease of insulin using selective intra-arterial in-jection of calcium and subsequent measurement of insulin levels in the hepatic veins. We report here a case of multiple pancreatic insulinomas measuring 3.0 x 2.1 x 2.0 cm ( head) and 1.0 x 0.8 x 0.3 cm (body) not seen by imaging techniques but localized by intra-arterial calcium stimula-tion with hepatic venous sampling and intraop-erative ultrasound imaging. This is the first se-lective intra-arterial calcium stimulation with hepatic venous sampling for localization of pan-creatic insulinoma in the Philippines.