Pregnancy of unicornuate uterus complicated with rudimentary horn: a case report and review of the literature.

BACKGROUND: Unicornuate uterus with rudimentary horn is a rare Müllerian anomaly associated with high-risk ectopic pregnancies. This report highlights the diagnostic challenges and management strategies for rudimentary horn pregnancy, emphasizing the role of advanced imaging in prerupture detection. CASE PRESENTATION: A 24-year-old nulliparous Asian woman presented with 48-day amenorrhea and a pelvic mass. Transvaginal three-dimensional ultrasound revealed a left unicornuate uterus and a right noncommunicating rudimentary horn containing a gestational sac. Emergency laparoscopic resection of the rudimentary horn and ipsilateral salpingectomy were performed, with histopathology confirming placental implantation. CONCLUSIONS: Rudimentary horn pregnancy necessitates a high index of suspicion in women with uterine anomalies. Prophylactic resection of the rudimentary horn and ipsilateral fallopian tube is recommended upon diagnosis to prevent catastrophic outcomes. Multimodal imaging combining three-dimensional ultrasound and magnetic resonance imaging improves preoperative detection accuracy.