1. Department of Pediatric Surgery; Keio University School of Medicine; Tokyo Japan
2. Department of Pathology; Kawasaki Municipal Hospital; Kanagawa Japan
3. Department of General Surgery; Keio University School of Medicine; Tokyo Japan
4. Department of Digestive and Transplantation Surgery; Tokyo Medical University Hachioji Medical Center; Tokyo Japan
5. Department of Hepatobiliary and Pancreatic Surgery; Tokyo Medical and Dental University; Tokyo Japan
6. Department of Pathology; Keio University School of Medicine; Tokyo Japan