1. Unit of Digestive Endoscopy, San Paolo Hospital, Via A. Di Rudiní, No. 8, 20142 Milano, Italy
2. HPB Endoscopy, Royal Free Hospital, London, UK
3. Department of Medical and Surgical Sciences (DIMEC), University of Bologna, Bologna, Italy
4. Department of Medicine and Pharmacology, University of Messina, Hospital “G. Martino”, Via Consolare Valeria, 98124 Messina, Italy
5. Department of Surgery, Unit of Hepatobilyopancreatic and Digestive Surgery, San Paolo Hospital, University of Milan, Via A. Di Rudiní, No. 8, 20142 Milano, Italy
6. Unit of Digestive Endoscopy, Istituto Clinico Humanitas Mater Domini, Via Gerenzano 2, 21053 Castellanza, Italy