1. General Surgery Service, Department of Surgery, Centro Hospitalar Universitário do Porto , EPE, 4099-001 Porto, Portugal
2. Hepatobiliary and Pancreatic Unit, Department of Surgery, Centro Hospitalar Universitário do Porto , EPE, 4099-001 Porto, Portugal
3. Anatomical Pathology Service, Department of Pathology, Centro Hospitalar Universitário do Porto , EPE, 4099-001 Porto, Portugal