Adenocarcinoma of the minor duodenal papilla: report of a case.

An 81-year-old male was found to have a duodenal tumor by screening upper gastrointestinal endoscopy. The tumor was located in the minor duodenal papilla. Pathological examination of the biopsy specimen revealed adenocarcinoma, and endoscopic ultrasound showed an elevated hypoechoic mass in the minor duodenal papilla. The preoperative diagnosis was therefore considered to be either adenocarcinoma of the minor duodenal papilla or duodenal cancer. We performed a subtotal stomach-preserving pancreaticoduodenectomy. Histopathological examination of the resected specimen showed the tumor cells to be primarily located in the submucosa of the minor duodenal papilla, with slight invasion into the pancreatic parenchyma through the accessory pancreatic duct. We therefore diagnosed a primary adenocarcima of the minor duodenal papilla. Adenocarcinoma of the minor duodenal papilla is considered to be a rare disease, but it may be underestimated because of the difficulty in distinguishing advanced adenocarcinoma of the minor duodenal papilla from primary duodenal cancer and cancer of the pancreatic head.