1. Division of Hepato-Biliary-Pancreatic Surgery and Transplant Surgery, Department of Surgery, Asahikawa Medical University, Hokkaido, Japan
2. Division of Hepato-Biliary-Pancreatic Surgery and Transplant Surgery, Department of Surgery, Asahikawa Medical University, 2-1-1 Midorigaoka Higashi, Asahikawa, Hokkaido 078-8510, Japan
3. Department of Diagnostic Pathology, Asahikawa Medical University Hospital, Hokkaido, Japan