Pregnancy-Associated Torsion of an Ovarian Dermoid Cyst: A Case Report

We report the case of a 27-year-old woman, gravida 2, para 1, with one living child (G2P1L1), who presented at 20 weeks of gestation with a 15-day history of left-sided abdominal pain that had become severe and refractory to analgesics.Transabdominal ultrasonography showed a large (13 × 12 × 10 cm) complex left adnexal mass with solid-appearing papillary projections without internal vascularity on color Doppler interrogation, corresponding to Ovarian-Adnexal Reporting and Data System (O-RADS) category 4. Subsequent non-contrast pelvic magnetic resonance imaging (MRI) revealed a hemorrhagic cystic lesion with no detectable macroscopic fat and a twisted left fallopian tube and vascular pedicle, findings suggestive of adnexal torsion.The patient underwent emergency laparoscopic left salpingo-oophorectomy for a gangrenous adnexal mass, and histopathological examination confirmed a mature cystic teratoma with gangrenous changes.The pregnancy continued without complication, and a healthy male neonate was delivered at term.In this case, no macroscopic fat was detected on imaging, possibly because of torsion-related hemorrhage and necrosis, and the lesion mimicked a malignant adnexal mass on ultrasonography.Recognition of the twisted vascular pedicle on non-contrast MRI redirected the working diagnosis from suspected malignancy to torsion.Torsion with hemorrhagic or necrotic change may obscure the typical imaging appearance of a mature cystic teratoma, and a twisted vascular pedicle on non-contrast MRI may provide an important diagnostic clue when sonographic findings are inconclusive.