Unicornuate uterus and endometrial cyst of the ovary in a 15-year-old female: a case report

Müllerian duct anomalies are congenital malformations of the female reproductive tract with diverse clinical presentations, ranging from asymptomatic cases to those associated with significant reproductive and gynecological complications. An unicornuate uterus with a rudimentary horn is a rare subtype of these anomalies. A 15-year-old girl presented with acute abdominal pain. Ultrasound revealed a solid left ovarian tumor, initially suspected to be a teratoma. Laboratory findings showed elevated Ca-125 (60 U/ml; normal: <35 U/ml), while other tumor markers were normal. Pelvic magnetic resonance imaging (MRI) suggested uterus didelphys with a left ovarian mass. During laparoscopy, a unicornuate uterus with a non-communicating rudimentary horn and a left ovarian tumor was identified. The ovarian tumor was excised with preservation of residual ovarian tissue. Histopathological analysis revealed the diagnosis of an endometrial cyst. Six months later, during an elective laparoscopy, a non-communicating left rudimentary horn with the ipsilateral fallopian tube was excised using LigaSure® device. The postoperative course was uneventful. She recovered well and remains under gynecological follow-up, with regular menstrual cycles. In pediatric and adolescent patients diagnosed with ovarian endometriotic cysts, a comprehensive evaluation of uterine anatomy is essential to exclude underlying obstructive Müllerian anomalies, as timely recognition and management may prevent progression of disease and preserve future reproductive potential.