S3385 An Uncommon Tumor With Devastating Consequences: Lessons From a Case of Metastatic VIPoma

Introduction: VIPomas are rare pancreatic tumors that secrete vasoactive intestinal polypeptide (VIP), a neuropeptide that promotes smooth muscle relaxation, stimulates pancreatic secretion, and suppresses gastric acid. Symptoms include watery diarrhea, hypokalemia, achlorhydria, and flushing. We present a case of metastatic VIPoma complicated by biliary obstruction and hepatorenal syndrome. Case Description/Methods: A 51-year-old man presented with a 1-year history of chronic secretory diarrhea, weight loss, and flushing. He had elevated VIP levels and a pancreatic mass with nodal involvement and was diagnosed with metastatic VIPoma. He underwent distal pancreatectomy, splenectomy, and cholecystectomy in 2016. He had multiple recurrences despite somatostatin analogs, PRRT (Lutathera), liver-directed therapies (TACE, ablation), targeted agents, and chemotherapy. In January 2025, he was admitted with common bile duct obstruction, along with progressive liver involvement and widespread nodal metastasis. He developed acute liver failure, hepatorenal syndrome, electrolyte derangements, and encephalopathy. Due to multiorgan decline, GI intervention was deferred, and he transitioned to hospice. Discussion: VIPomas are rare (0.05–0.2 cases/million) but can cause life-threatening fluid and electrolyte loss. Diagnosis is often delayed due to overlap with other diarrheal illnesses; thus, many cases are metastatic at presentation. Localized tumors respond to resection and somatostatin analogs. Metastatic VIPomas require multimodal treatment. The liver is the most common metastatic site and may cause hepatic dysfunction or common bile duct obstruction via compression or invasion. Biliary stenting is unstudied in VIPoma but is often pursued based on outcomes in other cancers. This case highlights diagnostic challenges, treatment complexity, and the importance of considering VIPoma in persistent secretory diarrhea.