Ovarian torsion of a large mature cystic teratoma complicating early pregnancy: a rare case report.

Introduction and Importance: Adnexal torsion complicating early pregnancy is rare but should be suspected in pregnant women presenting with acute lower abdominal pain. Mature cystic teratomas (MCTs) are common benign ovarian tumors in women of reproductive age, but their occurrence during pregnancy complicated by torsion is rare. MCTs comprise 20% of all ovarian neoplasms and are commonly encountered in patients between 20 and 40 years of age. Early diagnosis is challenging due to overlapping symptoms with common pregnancy-related conditions, yet prompt recognition and intervention are crucial to preserve maternal and fetal outcomes. This case report aims to highlight the diagnostic and management challenges of adnexal torsion complicating early pregnancy. Case Presentation: We report the case of a 21-year-old primigravida from Northern Tanzania who presented at gestational age of 11 weeks and 4 days of gestation with a sudden-onset history of left lower abdominal pain for 6 h that progressively worsened over time. Abdominal ultrasonography revealed a large left adnexal cystic mass with internal echoes, thickened walls, and posterior acoustic enhancement, measuring 14.0 × 10.4 × 9.3 cm, consistent with a complex ovarian cyst. The uterus was enlarged and contained a viable intrauterine pregnancy with a crown-rump length of 48.6 mm, corresponding to 11 weeks and 4 days of gestation with active cardiac activity. The patient underwent an emergency laparotomy, which confirmed a viable intrauterine pregnancy alongside a large, twisted left ovarian cystic mass measuring 19.0 × 14.0 × 10.0 cm, with torsion of its pedicle around the mesovarium. Detorsion and left salpingo-oophorectomy were performed successfully. Histopathological examination confirmed the diagnosis of a MCT. Postoperative recovery was uneventful, and follow-up at 23 weeks showed a viable ongoing pregnancy. Clinical Discussion: MCTs are prone to torsion due to their size and mobility. Early surgical management is critical to prevent ischemic necrosis and ensure optimal maternal and fetal outcomes. In this case, a timely laparotomy and removal of the affected adnexa resulted in a favorable recovery and continuation of pregnancy. Conclusion: Ovarian torsion due to a MCT in early pregnancy is a rare but important differential diagnosis for acute abdominal pain. Prompt recognition and surgical intervention are vital to preserving maternal health and supporting pregnancy continuation.