A case of retroperitoneal ectopic pregnancy diagnosed using exploratory laparoscopy

Abstract

Retroperitoneal ectopic pregnancy (REP) is rare. Laparoscopy is useful to diagnose a typical ectopic pregnancy and for removal of trophoblastic tissue. We report a case of REP diagnosed using exploratory laparoscopy. A 30-year-old, gravida 3 para 0 was admitted to our hospital with a history of 5 weeks' amenorrhea and suspected an ectopic pregnancy because of the empty uterus. Her obstetric history included a spontaneous abortion 8 years prior and laparoscopic left salpingectomy for a left tubal pregnancy, 6 years prior to presentation. She was completely asymptomatic and hemodynamically stable. Her serum human chorionic gonadotropin (hCG) level on admission was 3268 mIU/mL, which subsequently increased to 5654 mIU/mL, 2 days later. Transvaginal ultrasonography revealed a slightly edematous right fallopian tube. Exploratory laparoscopy was performed for suspected right tubal pregnancy; however, we did not detect any evidence of ectopic pregnancy. The serum hCG levels continued to increase postoperatively. Contrast-enhanced computed tomography performed to screen for trophoblastic disease revealed a ring-enhancing cystic mass in the left paraaortic region. Transabdominal ultrasonography revealed a gestational sac-like mass without a yolk sac and fetal heartbeat. We performed laparotomy and identified the gestational sac in the retroperitoneal space and removed all trophoblastic tissue. Diagnosis of REP is challenging on routine ultrasonography on routine evaluation. Exploratory laparoscopy is useful in the diagnosis of REP together with other imaging modalities to exclude other conditions.