Options for preserving fertility in children and adolescents with cancer depend on patient age, the available time frame, and the treatment regimen. Ovarian stimulation with mature oocyte preservation is often the optimal method in post-menarcheal adolescents. We describe a case of a 17-year-old girl with vaginal soft-tissue Ewing sarcoma in whom transvaginal oocyte collection for fertility preservation was ruled out by the large tumor. To overcome the limitations of the transabdominal approach, we applied a novel method of laparoscopically-assisted ultrasound-guided percutaneous transabdominal oocyte collection. In this manner, we were able to both perform oophorectomy and obtain superficial and deep ovarian follicles for cryopreservation.