Portal annular pancreas, an anomaly consisting of a hypertrophic uncinate process wrapped around by the superior mesenteric vein (SMV), occurs rarely. We report the case of a patient with duodenal papillary carcinoma with a portal annular pancreas and replaced right hepatic artery (RHA). A 62-year-old female with obstructive jaundice was diagnosed as having a duodenal papillary tumor and underwent subtotal stomach-preserving pancreaticoduodenectomy. The anomaly of replaced RHA from the superior mesenteric artery was confirmed preoperatively by CT. During the operation, we found an anomaly in which the uncinate process of the pancreas extended and fused with the dorsal surface of the body of the pancreas surrounding the SMV, with the replaced RHA running along the dorsal pancreas. The main pancreatic duct ran along the ventral side of the SMV. We resected the body of the pancreas along the left side of the SMV. The resected uncinate process of the pancreas was closed. Postoperatively, a pancreatic fistula occurred, which, however, resolved with conservative management.