† These authors contributed equally.
Background: Ovarian tissue cryopreservation (OTC) is a valid procedure that may allow to preserve endocrine and reproductive health in girls and young women at high risk of premature ovarian failure. At disease remission, the OTC may be transplanted in the woman, allowing recovery of the production of oocytes and reproductive hormones. Case: This report describes the case of a Ewing Sarcoma/Primitive Neuroectodermal Tumor (ES/PNET) survivor who cryopreserved ovarian tissue after the first line of chemotherapy. After completion of treatment the patient experienced premature ovarian failure. Seven years later ovarian tissue autotransplantation was performed and ovarian function recovery was obtained in a few months. The woman had a shoulder ES/PNET recurrence and restarted the chemotherapy. The menstrual cycle reappeared 4 months after the second line of treatment and the patient spontaneously conceived 10 months later giving birth to a healthy girl. Conclusions: In malignancies OTC performed even after the start of chemotherapy seems to be effective in preserving fertility and allows more women to become candidates for ovarian function preservation.