Ruptured Heterotopic Pregnancy at the Uterotubal Junction (Cornual/Interstitial Region) After Natural Conception: Successful Surgical Medical Management and Ongoing Intrauterine Pregnancy

Heterotopic pregnancy involving implantation at the uterotubal junction (cornual/interstitial region) after spontaneous conception is rare and carries a high risk of rupture and hemorrhage. Because the intrauterine pregnancy may mask the ectopic component, diagnosis is often delayed and can be life-threatening. We describe a 31-year-old multiparous woman who presented at 9 weeks of amenorrhea with abdominal pain and spotting. She was hypotensive and tachycardic on admission. Transvaginal ultrasound demonstrated a viable intrauterine pregnancy alongside a second gestational sac located at the right uterotubal junction (cornual/interstitial region) with free intraperitoneal fluid. Due to the emergency presentation, definitive differentiation between cornual implantation and interstitial pregnancy could not be fully documented using three-dimensional coronal reconstruction. Laparotomy confirmed rupture of the ectopic gestation at the right uterotubal junction. Cornual resection was performed, and intraoperative local methotrexate was administered at the resection site to reduce the risk of residual trophoblastic tissue. The patient required a blood transfusion, progesterone support, and treatment for a concomitant Trichomonas vaginalis infection. She recovered well, and the intrauterine pregnancy remained viable, with normal fetal growth documented at 26 weeks. This case highlights that prompt recognition and tailored surgical–medical management can be life-saving while preserving an ongoing intrauterine pregnancy.