Importance of Selective Arterial Calcium Stimulation with Hepatic Venous Sampling in Management of a Patient with Multifocal Insulinoma

Insulinoma is a rare neuroendocrine tumour arising from beta cells of pancreatic islets of Langerhans. We report a case of insulinoma presented with vague manifestations, which were undiagnosed for 2 years. The diagnostic evaluation revealed endogenous hyperinsulinism and imaging showed a pancreatic head lesion for which she underwent the surgery. Due to persisting symptoms, Calcium arterial stimulation and hepatic venous sampling was later performed and it localized an occult insulinoma that was not visible during the radiological or surgical assessment. Diagnosis of occult insulinomas remains a clinical challenge. Selective arterial calcium stimulation and venous sampling is a reliable pre-operative procedure for the positive diagnosis of insulinoma.