Occasional involvement of the ovary in Ewing sarcoma

BACKGROUND: Ewing sarcoma (EWS) is a highly metastatic malignancy in young patients. Ovarian cryopreservation is often an option for fertility preservation in cancer patients of reproductive age, specifically in minors. Thus, the possibility of ovarian involvement in EWS needs to be elucidated. METHODS: Eight patients aged 13-20 years with EWS participated in the study. Ovarian samples were fixed and prepared for light microscopy, and frozen in liquid nitrogen for RNA extraction followed by RT-PCR. Histological studies, including immunostaining for the adhesion receptor CD99, were used to detect histopathological features. Sensitive molecular methods were used to detect translocations causing the formation of tumor-specific EWS Friend leukemia virus integration site 1 fusion gene (EWS-FLII). RESULTS: In seven patients, there was no evidence of EWS in the ovaries from pathological/molecular studies. However, in one patient, the RT-PCR showed the EWS translocation, although there was no pathological evidence. CONCLUSIONS: Ovarian involvement is possible in EWS. Therefore, in patients with EWS ovarian tissue should be examined for traces of malignancy at both the pathological and molecular levels prior to the grafting of cryopreserved tissue in order to minimize the risk of reseeding the cancer.