Pancreatic acinar cell carcinoma with extensive tumor embolism at the trunk of portal vein and pancreatic intraductal infiltration.

A 59-year-old man was admitted to the hospital with acute pancreatitis. The cause was suggested to be a pancreatic tumor based on computed tomography (CT). The pancreatic tumor was 45 mm with an extensive tumor embolism at the trunk of the portal vein and intraductal infiltration of the main pancreatic duct (MPD). The pancreatic tumor was diagnosed as acinar cell carcinoma (ACC) by endoscopic ultrasound guided fine needle aspiration. Therefore, the cause of acute pancreatitis was diagnosed to be intraductal infiltration of ACC in the MPD. Chemotherapy was initially performed because it was difficult to perform surgery due to extensive tumor embolism at the trunk of the portal vein. Degeneration and reduction of ACC and tumor embolism of the portal vein was noted on CT after chemotherapy, and extended distal pancreatectomy with portal vein reconstruction was performed. There has been no relapse for 5 years postoperative follow-up. This is an interesting and rare case because ACC with intraductal infiltration of MPD is low in frequency; most ACCs are asymptomatic when they are found, and many cases tend to have poor prognosis in spite of surgical cases.