A Case Report of Retroperitoneal Ectopic Pregnancy and Review of Literature.

Background: Retroperitoneal ectopic pregnancy (REP) is a rare form of ectopic pregnancy, in which fertilised eggs are implanted in the retroperitoneal cavity. Due to its atypical location and non-specific symptoms, REP is often misdiagnosed, leading to delayed treatment. This condition poses serious risks owing to its proximity to the retroperitoneal blood vessels. Limited research and lack of specific guidelines make the management of REP challenging. Case Report and Literature Review: A 47-year-old woman with REP was initially misdiagnosed as having acute gastroenteritis due to severe abdominal pain and gastrointestinal symptoms. She had amenorrhoea and significant lower abdominal pain, but no vaginal bleeding. After 35 days of amenorrhoea, the patient's serum beta-human chorionic gonadotropin (β-hCG) level was 16111.94 mIU/mL. Imaging revealed no intrauterine gestational sac; however, a mass was detected in the left adnexal area. Emergency laparoscopy identified a 3.0 cm ectopic mass in the retroperitoneal space, adjacent to the lower edge of the left broad ligament and near critical structures, with surface rupture and bleeding. The mass was surgically removed, and the patient's β-hCG levels returned to normal 33 days post-surgery. In addition, we reviewed previously published English literature on REP, highlighting its characteristics, pathogenesis, diagnosis, and treatment with the aim of improving the understanding and management of the condition. Conclusion: REP is difficult to diagnose because of its rarity and nonspecific symptoms. Early diagnosis relies on serum β-hCG testing, ultrasonography, and radiological examination. When β-hCG is elevated and no gestational sac is found within the uterus or at common ectopic sites, REP should be considered. Surgical resection is the primary treatment for this condition.