Quirino Lai1, Alessandro Vitale2. 1. Hepato-biliary and Organ Transplant Unit, Department of Surgery, Sapienza University of Rome, Viale del Policlinico 155, 00161 Rome, Italy. Electronic address: lai.quirino@libero.it. 2. Department of Surgery, Oncology and Gastroenterology, University of Padua, Padua, Italy.