Résumé
Background and Objectives: Currently, one of the most useful prognostic indicators in Ewing sarcomas (ES) is the presence of metastatic disease at diagnosis. According to various clinical guidelines, the assessment of bone marrow (BM) metastases, using light microscopy examination of bone marrow aspirates and biopsies (BMAB) is mandatory. However, the prognostic value of BM positivity is discussed controversially. Therefore, the primary aim of this study was to retrospectively review BM samples from patients with ES. Materials and Methods: This retrospective single centre study included 31 patients that were newly diagnosed with ES between 2000 and 2014. Twenty-seven patients had skeletal ES and in 4 patients the tumour was localized in the soft tissue only. Metastases at diagnosis were present in 5 out of 31 patients. BM samples were morphologically and immunohistochemically searched and screened for the presence or absence of BM metastases. Furthermore, in 15 of the 31 patients BM samples were still available and were reanalysed, using nested-polymerase chain reaction. Results: All BM samples of our 31 ES patients, including the 5 metastatic patients, were, morphologically and immunohistochemically tested negative for tumour cell appearance. The nested-PCR results were also negative in all of our 15 retested patients, including two patients with metastatic disease. Conclusions: Based on our results and on the contradictory results reported in the literature we recommend a re-evaluation of the necessity and the prognostic value of BMAB in the initial staging process of newly diagnosed ES patients