S3616 Surveillance for Duodenopancreatic Neuroendocrine Tumors in Multiple Endocrine Neoplasia Type I

Introduction: Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder that predisposes to pituitary, parathyroid and duodenopancreatic neuroendocrine tumors (NETs). Malignant developments are leading causes of premature mortality in patients with MEN1. We report a case of asymptomatic gastrinoma detected by serum gastrin surveillance followed by endoscopic ultrasound (EUS)-guided biopsies in a MEN1 patient. Based on our medical literature review, a surveillance protocol for duodenopancreatic NETs in MEN1 is provided. Case Description/Methods: The patient is a 75-year-old man with confirmed MEN1 and a significant family history of MEN1 including paternal grandmother, father, 2 siblings, and 2 sons. He underwent a parathyroidectomy for a parathyroid adenoma in 1986 and an anterior pituitary resection for a pituitary macroadenoma in 2021. He was placed on a surveillance program which detected an elevated serum gastrin level at 932 pg/ml (normal <101 pg/ml). Abdominal computed tomography scan showed a 20 mm mass in the head of the pancreas. The patient had no Zollinger-Ellison syndrome symptoms such as abdominal pain, reflux, nausea, vomiting, diarrhea, gastrointestinal bleeding or weight loss. Endoscopy demonstrated mild esophagitis and gastritis with no abnormal findings in the duodenum. There were no peptic ulcers. EUS showed a 20 mm by 18 mm heterogeneous mass in the head of the pancreas. Fine needle biopsies were obtained. In-room microscopic evaluation demonstrated dense collections of uniform cells with oval nuclei consistent with a well-differentiated NET. Pathology reported malignant gastrinoma. The patient was referred to Oncology for management including a Whipple’s procedure. Discussion: MEN1 is an autosomal dominant disorder due to mutations in the tumor suppressor gene MEN1. Patients with MEN1 have a 15-year decrease in life expectancy due to malignant developments of NETs. Asymptomatic duodenopancreatic NETs are now recognized as the most common tumor type in MEN1 and are responsible for significant morbidity and mortality. Current medical management for NETs involves surgical resection of localized tumors as well as medications such as somatostatin analogs in the case of gastrinoma and insulinoma. Based on our medical literature review, we recommend a rigorous surveillance protocol. Such a protocol can detect duodenopancreatic NETs early, leading to timely interventions and reduction of morbidity and mortality, as illustrated by this case report.