An Unusual Cause of Acute Pancreatitis

createctomy to treat T2N1M0 pancreatic tail cancer. After six weeks of surgery, the patient’s general condition was good, and a total of six cycles of primary adjuvant chemotherapy with 5-fluorouracil (5-FU) (425 mg/m) and folic acid (20 mg/m) every four weeks was planned. After the end of the third cycle of chemotherapy, the patient visited the emergency room with epigastric pain and mild fever. The blood tests revealed 635 IU/L amylase and 559 IU/L lipase. The other laboratory results were within the normal ranges. Abdominal computed tomography (CT) revealed fluid collection at the pancreatic resection margin with diffuse mesenteric and omental infiltration in the pericolic (hepatic flexure colon, transverse colon), perigastric, and periduodenal regions (Fig. 1). There was no evidence of postoperative leakage of pancreatic juice, recurring pancreatic cancer, or gallstones. He had not taken any over-the-counter drugs and had no history of alcohol consumption or other risk factors commonly associated with pancreatitis. The diagnosis of acute pancreatitis was made without a definite etiology. During the next two weeks, he received conservative care and bowel rest with intravenous hydration. The complaint symptoms were diminished and pancreatic enzyme levels were also normalized. He was discharged from the hospital and planned to be admitted again on his next scheduled chemotherapy day. However, a recurrent pancreatitis episode occurred two days following the completion of the 5-FU infusion in the next (fourth) cycle. At that time, severe abdominal pain persisted, and the serum amylase and lipase levels had increased to 419 IU/L and 393 IU/L, respectively. A CT scan was performed and revealed that inflammatory infiltration into the mesentery and omentum had progressed more extensively than in the previous examination. Multiple large pseudocysts were observed around the pancreas (Fig. 2). However, the cause of recurrent pancreatitis was not clearly determined in the CT scan or the following magnetic resonance imaging. All the possible common causes of acute pancreatitis were excluded. Moreover, considering the relationship between the time of administration of the chemotherapeutic agents and the recurrence of pancreatitis follow-