Retroperitoneal tumors are relatively rare, accounting for 0.2% of all cancers; many different histologic types are present, and primitive retroperitoneal germ cell tumors constitute a small miniority of about 3%. Most primary extragonadal germ cell tumors (EGCTs) arise from the mediastinum of retroperitoneum in young males. The authors experienced a case of primary extragonadal mixed germ cell tumor with a 43-year-old woman complaining left lower abdominal pain. With the case report, a brief review was made.