1. University of Rome “La Sapienza,” II° Faculty of Medicine and Surgery, Azienda Ospedaliera Sant'Andrea, Hepatobiliary and Pancreatic Surgery, Rome, Italy
2. Department of General Surgery, University of Modena and Reggio Emilia, Modena, Italy
3. University of Rome “La Sapienza,” II° Faculty of Medicine and Surgery, Azienda Ospedaliera Sant'Andrea, Servizio di Endocrinologia, Rome, Italy;
4. Department of General Surgery, Sant'Agostino Hospital, Modena, Italy