ENDOSCOPIC ULTRASOUND(EUS) MAY BE SUPERIOR TO SOMATOSTATIN RECEPTOR SCINTIGRAM (OCTREOSCAN) IN THE EVALUATION OF GASTRINOMA

Abstract

Hypergastrinemia which is commonly associated with either atrophic gastritis or the use of acid-suppressive therapy in the community setting, could also be rarely due to gastrinoma. Elevated levels of gastrin of more than 200-fold should trigger further evaluation for gastrinoma. Such evaluations typically involve octreoscan, computed tomography(CT scan) and magnetic resonance imaging(MRI) in the community setting. In this clinical vignettes, we present a case of a 55 year old gentleman who had a negative CT scan and otreoscan in the evaluation of gastrinoma. Patient had previously presented with weight loss, abdominal pain and elevated serum levels of amylase and lipase suggestive of clinical pancreatitis. His other pertinent symptoms included minimal gastroesophageal reflux symtoms, diarrhea and weakness. Subsequent upper endoscopy showed esophagitis and antral ulcer. Fasting serum gastrin level done was over 2200 pg/ml. Initial work-up to evaluate for gastrinoma included negative abdominal CT scan, MRI and octreoscan. EUS with fine needle aspiration(FNA) showed a peripancreatic mass. Specimen from the FNA done with appropriate immunohistochemical stains revealed gastrinoma. Subsequent exploratory laparotomy and intraoperative ultrasound showed metastatic gastrinoma confirmed by positive tumor cells in the lymph nodes. During the above work-up, treatment with proton pump inhibitor resulted in improvement of his symptoms In this presentation, the use of EUS with FNA enabled the appropriate diagnosis to be made prior to surgery. Further studies may be necessary to confirm the superiority of EUS over octreoscan in the evaluation of gastrinoma