An 11-year-old and 8-month-old obese girl before menarche presented with pain in the right lower part of the abdomen lasting 40 hours. Ultrasound showed a large right-sided cystic mass with a “hot tub sign” (O-RADS 2) and CT confirmed a pelvic cystic lesion with minimal fluid. On admission, she had elevated liver enzymes ALT 278 U/l and AST 122 U/l. Single-port laparoscopic surgery through the umbilicus revealed 540° torsion of the right adnexal pedicle, detorsion was followed by extracorporeal cystectomy with decompression, cyst wall excision, hemostasis and ovarian reconstruction. Blood loss was approximately 20 mL, transaminases normalized postoperatively, and the girl was discharged on the 4th day. Histopathology confirmed an ovarian follicular cyst with mild granulosa cell hyperplasia. This single-port approach with extracorporeal cystectomy is a safe minimally invasive solution to torsion in children, shortens operative time, minimizes CO2 exposure, and preserves ovarian function.