Adnexal Torsion Due to Borderline Mucinous Tumor of the Gonad in a Prepubertal Girl with Mixed Gonadal Dysgenesis (45,X/46,XY) and a Turner Phenotype

BackgroundTurner syndrome (TS) is a sex chromosome condition characterized by complete or partial loss of the X chromosome. Patients with mixed gonadal dysgenesis (45,X/46,XY) and a Turner phenotype are predisposed to gonadoblastoma with malignant transformation.CaseWe present the case of a TS patient with 45,X/46,XY with 2 episodes of left adnexal torsion (AT). Biopsies during detorsion showed benign mucinous cystadenoma. Pathology following bilateral gonadectomy revealed a left gonad with mucinous borderline tumor and right gonad with gonadoblastoma, both of which have malignant potential.Summary and ConclusionGonadectomy is recommended in XY gonadal dysgenesis to decrease risk of malignant transformation from gonadoblastoma. Although rare in pediatric patients, ovarian malignancies have been identified among AT cases. To our knowledge, we present the first case of AT due to borderline ovarian mucinous tumor of the ovary and contralateral gonadoblastoma in a patient with mixed gonadal dysgenesis (45,X/46,XY) and a Turner phenotype.