S3500 Bleeding From Ampulla of Vater: A Rare Diagnostic and Therapeutic Challenge

Introduction: Arteriovenous malformations (AVMs) are abnormal connections between arteries and veins that bypass the capillary system and lead to potential gastrointestinal bleeding (GIB). Although AVMs are most commonly located in the cecum and right side of the colon, their occurrence in the ampulla of Vater is exceedingly rare. Differentiating AVM-induced bleeding from hemobilia or hemosuccus pancreaticus poses significant diagnostic challenges owing to the intermittent nature of bleeding and suboptimal visualization of the ampulla with standard endoscopic techniques. Case Description/Methods: We report the case of a 67-year-old woman with end-stage renal disease who presented with recurrent melena. Initial esophagogastroduodenoscopy (EGD) revealed active bleeding from the ampulla but was inconclusive in identifying the source. Subsequent EGD enteroscopy and endoscopic ultrasound (EUS) revealed a prominent ampulla without active bleeding, with a positive Doppler signal in the distal common bile duct. Magnetic resonance cholangiopancreatography (MRCP) was non-diagnostic. The bleeding subsided without any intervention. Upon re-presentation with melena, combined forward-viewing gastroscopy and side-viewing duodenoscopy revealed active bleeding from the inferior aspect of the major papilla (below the orifice), ruling out hemobilia and haemosuccus pancreaticus. A non-arborizing AVM was identified, and hemostasis was achieved using a bipolar probe, resulting in complete resolution of the bleeding. After the procedure, the patient remained hemodynamically stable, and her hemoglobin level normalized without recurrence. Discussion: Ampullary AVMs, a rare but significant source of recurrent GI bleeding, are challenging to diagnose because of their rarity and the limitations of standard endoscopic views. Differentiating AVM from other conditions, such as hemobilia and hemosuccus pancreaticus, requires a combination of clinical, endoscopic, and imaging evaluations. In this case, visualization with a side-viewing duodenoscope identified active bleeding below the major papilla os, distinguishing it from the blood originating within the os. Endoscopic ultrasound provides critical insights by identifying a Doppler signal consistent with AVM, while MRCP excludes biliary obstructions or stones. Advanced endoscopic techniques such as endoscopic retrograde cholangiopancreatography (ERCP) and cholangioscopy using the SpyGlass system are invaluable for diagnosing and managing bleeding from the ampulla when standard modalities are inconclusive.