A strange case of acute abdomen.

A 30-year-old male suffered from acute abdomen following duodenal biopsy taken at esophagogastroduodenoscopy (EGD). Exploratory laparotomy showed a large retroperitoneal hematoma arising from the second part of the duodenum that was then treated conservatively. To the authors' knowledge, this is the first case of extensive retroperitoneal hematoma following EGD. The hemorrhage is speculated to have been caused by the tearing of one of the pancreaticoduodenal arteries or one of their branches during the duodenal biopsy.