The role of positron emission tomography (PET) molecular imaging for the localisation of insulinomas is yet to be determined. Recent evidence demonstrates the utility of PET molecular imaging for localisation, staging and directing therapy. We describe 2 cases of insulinomas demonstrating the utility of PET molecular imaging.
Case 1: A 62 year-old lady was admitted under the endocrine unit with recurrent severe hypoglycaemia. Dynamic testing was consistent with an insulinoma. Contrast enhanced Computer Tomography (CT) revealed an arterially enhancing mass in the pancreatic head >2cm raising suspicion for a malignant insulinoma. 68Ga-DOTA-TATE PET/CT revealed a 2.3cm pancreatic head lesion with high somatostatin receptor (SSR) expression, consistent with a well-differentiated insulinoma and no metastatic disease. The patient underwent a Whipple’s procedure confirming a pancreatic head insulinoma.
Case 2: A 64 year-old lady with type-2 diabetes mellitus presented with recurrent severe hypoglycaemia despite cessation of oral hypoglycaemic agents. Dynamic testing was consistent with an insulinoma. Contrast-enhanced CT was reported as a normal pancreas with a splenic hilum nodule - a splenunculus. Given the strong suspicion for an insulinoma a 68Ga-Exendin-4 PET/CT was performed which clearly localised an insulinoma at the site of the reported splenunculus. The patient underwent a laparoscopic resection of the lesion with histology confirming an insulinoma.