Retroperitoneal Ectopic Pregnancy: A Case Report

A retroperitoneal ectopic pregnancy is an extremely rare type of ectopic pregnancy and is difficult to diagnose and treat. Owing to its occult onset, it is life-threatening and often associated with high mortality. A 28-year-old woman was admitted to the emergency department of our hospital owing to soreness of the left lower quadrant of the abdomen and amenorrhea for 60 days. Dilatation and curettage were performed at a local hospital to induce abortion, but no gestational sac was found. Elevated plasma human chorionic gonadotropin levels suggested an ectopic pregnancy. An ultrasound showed an approximately 4.0 cm × 3.0 cm mass in front of the middle and upper poles of the left kidney. The plasma beta-human chorionic gonadotropin level was 99 286.00 mIU/mL. Under laparoscopy, an ovoid mass measuring approximately 4.0 cm × 5.0 cm below the left renal vessels and the abdominal aorta was successfully resected. Methotrexate (50 mg/m²) was locally injected, and the retroperitoneum was sutured. Villi were observed in histopathologic sections. This case report highlights the importance of considering the possibility of a retroperitoneal ectopic pregnancy for patients with abdominal pain. Laparoscopic surgery by an experienced surgeon is the preferred method of treatment for this condition.