1. First Department of Propaedeutic Surgery, Hippokration General Hospital of Athens, Athens 11527, Greece
2. Department of Endoscopy, Hippokration General Hospital of Athens, Athens 11527, Greece
3. Department of Pathology, Hippokration General Hospital of Athens, Athens 11527, Greece
4. Second Surgery Clinic, Aretaieio Hospital, Athens Medical School, National and Kapodistrian University of Athens, Athens 11528, Greece