Watermelon Duodenum (Duodenal Bulb Vascular Ectasia) in a Patient With Hepatocellular Carcinoma: A Rare Cause of Upper Gastrointestinal Bleeding.

Watermelon duodenum, also known as duodenal bulb vascular ectasia (DBVE), is a rare and under-recognized cause of upper gastrointestinal bleeding. Unlike its more commonly reported gastric counterpart - gastric antral vascular ectasia (GAVE) - DBVE is seldom described in the literature, and its clinical presentation, risk factors, and optimal management remain poorly defined. We report the case of an elderly patient with multiple complex comorbidities, including hepatocellular carcinoma, atrial fibrillation on anticoagulation, and chronic immune thrombocytopenia, who presented with worsening confusion and lethargy consistent with hepatic encephalopathy. Laboratory studies revealed anemia and elevated ammonia levels, raising suspicion for an upper gastrointestinal source of bleeding as a precipitating factor. Urgent esophagogastroduodenoscopy demonstrated isolated, longitudinally arranged vascular ectatic lesions confined to the duodenal bulb, producing a characteristic "watermelon" appearance. No involvement of the gastric antrum was noted. The lesions were treated endoscopically with hemostatic therapy, argon plasma coagulation (APC), resulting in clinical stabilization and improvement of encephalopathy. This case emphasizes the need for heightened clinical awareness of DBVE as a potential source of upper gastrointestinal bleeding. Early identification and appropriate endoscopic management can significantly improve outcomes, particularly in patients with complex comorbid profiles.