Unruptured pregnancy in a right non-communicating rudimentary horn mimicking an adnexal ectopic pregnancy: a rare case report at 12 weeks

Abstract

Pregnancy in a non-communicating rudimentary horn is a very rare form of ectopic pregnancy associated with Müllerian duct abnormality. The rudimentary horn has limited distensibility and carries a high risk of rupture and catastrophic intra-abdominal haemorrhage, while early diagnosis may be difficult because it can mimic a tubal ectopic pregnancy. A 28-year-old unbooked gravida 2 para 1 living 0 woman with 12 weeks of amenorrhoea presented with lower abdominal pain and vaginal bleeding for 2–3 days. Ultrasound suggested an approximately 12-week unruptured right adnexal ectopic pregnancy with absent fetal cardiac activity. Emergency exploratory laparotomy revealed an intact pregnancy in a right non-communicating rudimentary horn of a unicornuate uterus. The rudimentary horn and ipsilateral fallopian tube were excised after evacuation of the products of conception. The postoperative course was uneventful, and the patient was asymptomatic at six-week follow-up. This case highlights the diagnostic challenge of rudimentary horn pregnancy and the importance of early recognition and timely surgical management before rupture.