A Case Report of Retroperitoneal Ectopic Pregnancy and Review of Literature

Abstract

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.

Keywords: ectopic pregnancy; laparoscopy; retroperitoneal ectopic pregnancy; surgery; ultrasonography.

Figure 1

A round, mixed-density lesion was observed in the left adnexal region, measuring approximately 4.3×2.7 cm (as indicated by the arrow).

Figure 2

(A) The double-layered endometrial lining measured 0.6 cm in thickness. (B) Approximately 2.0 cm of pelvic fluid with multiple hypoechoic masses, likely blood clots, was detected. (C) An uneven echogenic mass, approximately 3.7×2.5 cm in size, was found in the left adnexal region. (D) No obvious blood flow signal was detected in this mass. (E and F) The mass was not connected to the left ovary.

Figure 3

(A) Hemoperitoneum was observed in the pelvic cavity. The uterus appeared enlarged with a smooth surface. (B and C) Pregnancy tissue, measuring approximately 3.0×3.0 cm, was located in the retroperitoneal space. (D) The ectopic pregnancy tissue was successfully removed.

Figure 4

Postoperative β-hCG levels during follow-up.