Rare embryonic tumor of the central nervous system – neuroblastoma with FOXR2-activation

Introduction. The development of technologies for molecular genetic typing of tumors of the central nervous system (CNS) has significantly increased the specificity of traditional histological and immunohistochemical research methods. As a result, completely new variants of tumors have appeared, as well as improved results of treatment of tumors with a long-term favorable prognosis. Thanks to new biomarkers, among morphologically similar small-cell embryonic CNS tumors, extremely rare tumors have been identified: ETMR (embryonic tumor with multiple rosettes C19MC), CNS NB-FOXR2 (CNS neuroblastoma (NB) with FOXR2-activation), CNS EFT-CIC (tumor of the CNS sarcoma family of sarcoma alteration), CNS HGNET-MN1 (neuroepithelial tumor of the CNS of high grade with MN1 alteration), CNS HGNET-BCOR (neuroepithelial tumor of the CNS of high grade with BCOR alteration).The aim of the study was to assess the historical prerequisites for the emergence of a new rare nosological form “CNS NB with FOXR2- activation”, as well as presentation of own results of diagnostics and treatment of children with this tumor.Materials and methods. The results of diagnosis and treatment of 7 patients with CNS NB with FOXR2-activation were studied. Tumor identification was carried out using a new DNA methylation technique for CNS tumor profiles using the Heidelberg (Germany) brain tumor classifier (www.molecularneuropathology.org), which has recently become available in Russia.Results and discussion. Based on a review of international experience, the evolution of the appearance in the classification of CNS tumors, as well as the clinical and molecular features of CNS neuroblastoma with FOXR2-activation are presented. The authors present their own results of diagnostics and treatment of 7 patients with a rare tumor CNS neuroblastoma with FOXR2-activation.Conclusion. Biomarkers have been proposed for the differential diagnosis of small-cell PNET-like tumors of the CNS in children. Due to the molecular identification of this tumor in children, it became clear that such patients, provided that the treatment protocol is adequately followed, have quite satisfactory long-term survival results.