A 74-year-old man presented with fever and abdominal pain. Choledocholithiasis-associated acute cholangitis was diagnosed by laboratory tests and abdominal CT. ERCP was performed. Wire-guided cannulation of the papilla, which was located adjacent to the duodenal diverticulum, was attempted; however, cannulation was achieved only in the main pancreatic duct. An additional papilla, partially concealed by the margin of the diverticulum, was identified on the oral side of the initially cannulated papilla. After cannulation of the second papilla, the common bile duct was successfully accessed, leading to the diagnosis of a double major papilla. This anatomical variant has been reported in approximately 0.18% of ERCP cases. Difficulty in recognizing the biliary opening may prolong the cannulation time and increase the risk of post-ERCP pancreatitis due to repeated pancreatic duct cannulation.
