Schema of the patient’s condition. (A) Stretching of and traction on the SMA by IPAA caused compression of the third portion of the duodenum (SMAS). (B) High pressure in the duodenum caused high pressure at the main pancreatic duct, resulting in PF formation. Pancreatic juice might have reduced the fat pad between the SMA and aorta, worsening SMAS. (C) After duodenojejunostomy, the duodenal pressure decreased and the overflow of pancreas juice from the pancreatic stump was subsequently reduced.