Laparoscopic cornuostomy combined with methotrexate intralesional injection for conservative management to interstitial pregnancy: a case report.

Introduction and importance: Interstitial pregnancy is a rare and potentially fatal type of ectopic pregnancy, comprising 2-4% of all ectopic cases. Deep myometrial implantation often leads to delayed diagnosis and a high risk of rupture. Early recognition and fertility-preserving management are essential, though the optimal conservative approach remains debated. Case presentation: A 24-year-old primiparous woman at 8 weeks of gestation presented with vaginal bleeding and abdominal pain. Transvaginal ultrasonography showed a viable left interstitial pregnancy with fetal cardiac activity and elevated β-hCG level of 59 588.4 mIU/ml. She underwent laparoscopic cornuostomy followed by intralesional methotrexate (1 mg/kg) injection under ultrasound guidance. The surgery was uneventful with minimal blood loss. β-hCG levels declined to negative within 1 month. At 5-month follow-up, ultrasonography and hysterosalpingography demonstrated a normal uterus and bilateral tubal patency. Clinical discussion: Interstitial pregnancy carries a sevenfold higher mortality risk than other ectopic types. In stable patients desiring fertility, conservative options are preferred. Laparoscopic cornuostomy minimizes uterine trauma compared to wedge resection, while intralesional methotrexate provides local trophoblastic control with limited systemic toxicity. The combination achieves effective resolution and preserves fertility. Conclusion: Laparoscopic cornuostomy combined with intralesional methotrexate is a safe and effective conservative treatment for interstitial pregnancy, providing excellent outcomes and fertility preservation through early diagnosis and individualized management.