Ovarian cysts are the most common abdominal tumors in female newborns. Among the acute and long-term complications, the most frequent is the adnexal torsion, which is difficult to recognize in the neonatal stage. Prenatal diagnosis is essential for the timely management of patients and ultrasound monitoring of adnexal cysts. There are different therapeutic alternatives where minimally invasive and conservative surgery plays an important role.

Cornual pregnancy is a rare entity associated with high morbidity and mortality. Diagnosis is challenging because the embryo usually appears on ultrasound as localized inside the uterus. Cornual pregnancy is more dangerous than other ectopic pregnancies, and cornual rupture may lead to severe maternal hemorrhage. It has the same risk factors as tubal pregnancy. Early diagnosis allows either medical treatment with methotrexate or conservative surgical treatments. We present a case of cornual pregnancy with unusual evolution to a single dose of methotrexate.