Ultrasonographic and Endoscopic Findings of Pancreatic Adenocarcinoma With Duodenal Invasion in a Brown Bear ( <i>Ursus arctos</i> )

This report describes a 25-year-old, intact male brown bear (Ursus arctos) presenting with weight loss, diarrhea, melena, apathy, and a 12% hematocrit. Ultrasound showed proximal duodenal wall thickening with submucosal cysts and a large, heterogeneous, highly vascularized mass in the descending duodenum, containing small gas pockets and compressing the lumen. The pancreas was visualized at the beginning of the descending duodenum, with normal echogenicity and slightly heterogeneous echotexture, containing a large cyst. Upper gastrointestinal endoscopy revealed bleeding and a partially obstructive duodenal mass with abundant fresh blood. A few days later, the animal died from hemorrhage as there were no possibilities for transfusion and consequently surgery. Histopathology revealed well-differentiated exocrine pancreatic adenocarcinoma infiltrating the duodenum. According to the scarce literature found, the ultrasonographic and endoscopic appearance of pancreatic adenocarcinoma in a brown bear has never been described.