P3220 - A Case of Synchronous Primary Pancreatic and Biliary Neuroendocrine Tumors With Multiple Endocrine Neoplasia Type 1

Stephen Tsoukas, MBBCh¹, Terry Jue, MD¹, Harsimran Kalsi, MBBS^2
1Mayo Clinic Arizona, Phoenix, AZ; ²HCA Florida North Florida Hospital, Gainesville, FL

Introduction: Multiple endocrine neoplasia type-1 (MEN-1) predisposes patients to pituitary, parathyroid and enteropancreatic tumors. Pancreatic neuroendocrine tumors (pNETs) carry metastatic potential, however, multiple sporadic lesions can occur simultaneously. We present a case of MEN-1 with synchronous primary low grade NET of the pancreas and intrahepatic bile ducts.

Case Description/Methods: A 71 year-old male with MEN-1 and a 10 year history of a stable 18mm pNET diagnosed by somatostatin receptor scintigraphy was evaluated for a 1 year history of episodic diarrhea and epigastric pain. Recent endoscopy noted necrotizing esophagitis, a 6mm Forrest III duodenal ulcer and negative H. pylori biopsies. Functional pNET was excluded including mild gastrin elevation (214 pg/mL) and normal VIP. There was unchanged mild left intrahepatic dilation on CT since 2015, however, a 1cm intraductal segment II lesion was seen on MRCP without any liver enzyme abnormality. EUS revealed two 12x10.8mm and 9.4x5.1mm hypoechoic pancreatic body masses, an ovoid hypoechoic 8.8x6.8mm intraductal left hepatic lobe mass and a 7x5.6mm hypoechoic falciform ligament node. A round left intrahepatic mass was seen on ERCP and cholangioscopy. Fine needle biopsy of the larger pancreatic mass and intraductal biopsies were consistent with grade 1 well differentiated NETs (Ki-67 0.89-1%). There was uptake within the right lung base and a 9mm peripancreatic node on PET-DOTATATE. No suspicious pulmonary lesions, hepatic metastases or tumor enlargement was seen on CT or repeat MRI. Given the unchanged < 2cm G1 pNET and chronicity of biliary abnormalities, findings were consistent with concurrent primary non-functional (NF) pNET and intrahepatic biliary NET rather than metastases. Surveillance was pursued with surgical consideration in the event of future progression.

Discussion: Management of small low-grade sporadic NF-pNETs remains controversial and is compounded by multicentric disease in MEN-1. Low Ki-67 index, size < 2cm, and low grade are associated with significantly lower rates of metastases (3.4%). The North American Neuroendocrine Tumor Society recommends non-metastatic low grade NF-pNETs < 2cm be surveilled, and high quality data supporting systemic therapy in such patients is scarce. Primary biliary NETs are rare, accounting for 0.2-2% of all NETs, and < 2% of these are intrahepatic. No evidence-based guidelines exist for managing asymptomatic primary biliary NETs, however symptomatic extrahepatic NETs may require excision.


Disclosures:


Stephen Tsoukas, MBBCh¹, Terry Jue, MD¹, Harsimran Kalsi, MBBS². P3220 - A Case of Synchronous Primary Pancreatic and Biliary Neuroendocrine Tumors With Multiple Endocrine Neoplasia Type 1, ACG 2023 Annual Scientific Meeting Abstracts. Vancouver, BC, Canada: American College of Gastroenterology.