4th Department of Surgery;
National and Kapodistrian University of Athens;
Attikon University Hospital;
1st Department of Surgery;
National and Kapodistrian University of Athens;
Laikon Hospital;
Hannover Medical School;
Clinic for General;
Visceral and Transplant Surgery;
3rd Department of Surgery;
National and Kapodistrian University of Athens;
Attikon University Hospital;
1st Department of Pathology;
National and Kapodistrian University of Athens;
Retroperitoneal; tumours; Synovial; sarcoma; Case; report; Clinical; presentation; Diagnostic; modalities; Therapeutic; management;