Skip to main content

CNS neuroblastoma, FOXR2-activated and its mimics: a relevant panel approach for work-up and accurate diagnosis of this rare neoplasm

The “neuroblastoma of the central nervous system” (CNS) has been referenced in the World Health Organization’s (WHO) classification of brain tumors since 1993 [2]. However, in recent years, thanks to molecular analyses, forkhead box R2 (FOXR2) alterations have become associated with this tumor type and as a result, the WHO classification renamed the neoplasm “CNS neuroblastoma (NB), FOXR2-activated” [4, 5]. These alterations are comprised of complex structural rearrangements for which routine testing is not easily implemented [4]. Consequently, the diagnosis is confirmed using advanced molecular techniques (Next-generation sequencing or DNA-methylation profiling) [3]. In this context, routine biomarkers for neuropathologists are needed to facilitate a NB-FOXR2 diagnosis. The aims of this report are to present the French national RENOCLIP-LOC network’s experience diagnosing NB-FOXR2 and to propose an alternative diagnostic approach.

Our study included a total of 24 cases initially suspected to be NB-FOXR2, based on histopathology alone, and reviewed by the French national network. All tumors were pediatric (except one in a young adult) and located in the supratentorial region. We performed an immunohistochemical (IHC) panel (including Olig2, synaptophysin, vimentin, and SOX10), fluorescent in situ (FISH) analysis of chromosome 1, and DNA-methylation profiling for all tumors. Each maintained BRG1 and INI1 expression and showed no immunoexpression for Lin28A.

DNA-methylation profiling using the CNS tumor Classifier supported the NB-FOXR2 diagnosis in 9/24 cases (37%), with a calibrated score (> 0.9) for nine of the samples. The other diagnoses having scores > 0.9 included: high-grade gliomas, IDH- and H3-wildtype (n = 2); glioneuronal tumors not otherwise specified, subtype A (n = 2); a diffuse glioneuronal tumor with oligodendroglioma-like features and nuclear clusters (DGONC); an anaplastic neuroepithelial tumor with condensed nuclei (ANTCON) [1]; a CNS embryonal tumor with BRD4::LEUTX fusion; a CNS tumor BCOR-altered; and a neuroepithelial tumor, PLAGL1-fused. An orthogonal validation, using different molecular techniques, confirmed these diagnoses (cf. Additional file 1: Table 1). The six remaining cases presented a low calibrated score for different methylation classes. All cases were included in a t-distributed stochastic neighbor embedding analysis to better characterize tumors with low scores. Finally, 10/24 cases were confirmed as NB-FOXR2.

From these results, we tested the sensitivity/specificity of different technical approaches using IHC, FISH, or combinations of these different techniques. The best diagnostic panel included an IHC panel (showing Olig2, synaptophysin, and SOX10 immunopositivities without vimentin immunoexpression), and FISH analysis (presence of 1q gain) with a very high sensitivity/specificity (Fig. 1 and Additional file 2: Figure 1).

Fig. 1
figure 1

Flowchart of the study. Different technical panels used: panel 1 (Olig2 and synaptophysin immunopositivities, and vimentin negativity); panel 2 (Olig2, synaptophysin and SOX10 immunopositivities); panel 3 (Olig2, synaptophysin and SOX10 immunopositivities, and vimentin negativity); panel 4 (Olig2, synaptophysin and SOX10 immunopositivities, and vimentin negativity, and 1q gain). The sensitivity and specificity for each panel were: 100 and 71% (panel 1); 100 and 50% (panel 2); 100 and 86% (panel 3); and 100 and 100% (panel 4)

In accordance with the WHO Classification, our work evidenced that a diagnosis of NB-FOXR2 based on morphology alone is currently not possible. Indeed, many differential heterogeneous diagnostic pitfalls exist, including glial, glioneuronal, embryonal and new emerging tumor types. Many of these have been very recently described in the literature and are not yet listed in the latest WHO classification, highlighting the velocity with which CNS tumors are being deciphered in recent years thanks to DNA-methylation profiling, and thus, their increasing complexity. The essential diagnostic criteria of the WHO classification defines NB-FOXR2 as an embryonal tumor having foci of neuroblastic or neuronal differentiation and a FOXR2 activation or a DNA-methylation profile aligned with this diagnosis. These genetic or epigenetic diagnostic techniques are not routinely used or available in all countries worldwide. However, IHC and FISH analyses are well established, can be automated, are relatively easy to standardize, are less expensive, and are widely available in most pathology laboratories worldwide. In this context, the national French histopathological network’s experience showed that IHC (confirming the necessity of a co-expression of Olig2 and synaptophysin, and the interest of SOX10 immunopositivity) and FISH analyses (confirming the necessity of chromosome 1q gain) may improve the diagnosis of NB-FOXR2, and help eliminate potential mimickers [3, 4].

In conclusion, the diagnosis of NB-FOXR2 may be ameliorated by using an algorithmic approach that includes several criteria based on histopathology, IHC and FISH analysis. This diagnostic panel can be tested in further series in order to be validated as a working formula that facilitates the diagnostic approach and reaches an accurate diagnosis in a resource-limited environment.


  1. Jones D, Ismer B, Schrimpf D, Reuss D, Stichel D, Casalini B, Schittenhelm J, Frank S, Boldt H, Winther-Kristensen B, Sehested AM, Scheie D, Korshunov A, Ecker J, Milde T, Pajtler K, Herold-Mende C, Witt O, Wick W, Pfister SM, von Deimling A, Sahm F (2019) Gene-12. Anaplastic neuroepithelial tumor with condensed nuclei (ANTCON): a novel brain tumor entity with recurrent NTRK fusion. Neuro-Oncol 21:ii83.

    Article  PubMed Central  Google Scholar 

  2. Kleihues P, Burger PC, Scheithauer BW (1993) Histological typing of tumours of the central nervous system, 2nd edn. Springer, Berlin

    Book  Google Scholar 

  3. Korshunov A, Okonechnikov K, Schmitt-Hoffner F, Ryzhova M, Sahm F, Stichel D, Schrimpf D, Reuss DE, Sievers P, Suwala AK, Kumirova E, Zheludkova O, Golanov A, Jones DTW, Pfister SM, Kool M, von Deimling A (2021) Molecular analysis of pediatric CNS-PNET revealed nosologic heterogeneity and potent diagnostic markers for CNS neuroblastoma with FOXR2-activation. Acta Neuropathol Commun 9:20.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  4. Sturm D, Orr BA, Toprak UH, Hovestadt V, Jones DTW, Capper D, Sill M, Buchhalter I, Northcott PA, Leis I, Ryzhova M, Koelsche C, Pfaff E, Allen SJ, Balasubramanian G, Worst BC, Pajtler KW, Brabetz S, Johann PD, Sahm F, Reimand J, Mackay A, Carvalho DM, Remke M, Phillips JJ, Perry A, Cowdrey C, Drissi R, Fouladi M, Giangaspero F, Łastowska M, Grajkowska W, Scheurlen W, Pietsch T, Hagel C, Gojo J, Lötsch D, Berger W, Slavc I, Haberler C, Jouvet A, Holm S, Hofer S, Prinz M, Keohane C, Fried I, Mawrin C, Scheie D, Mobley BC, Schniederjan MJ, Santi M, Buccoliero AM, Dahiya S, Kramm CM, von Bueren AO, von Hoff K, Rutkowski S, Herold-Mende C, Frühwald MC, Milde T, Hasselblatt M, Wesseling P, Rößler J, Schüller U, Ebinger M, Schittenhelm J, Frank S, Grobholz R, Vajtai I, Hans V, Schneppenheim R, Zitterbart K, Collins VP, Aronica E, Varlet P, Puget S, Dufour C, Grill J, Figarella-Branger D, Wolter M, Schuhmann MU, Shalaby T, Grotzer M, van Meter T, Monoranu C-M, Felsberg J, Reifenberger G, Snuderl M, Forrester LA, Koster J, Versteeg R, Volckmann R, van Sluis P, Wolf S, Mikkelsen T, Gajjar A, Aldape K, Moore AS, Taylor MD, Jones C, Jabado N, Karajannis MA, Eils R, Schlesner M, Lichter P, von Deimling A, Pfister SM, Ellison DW, Korshunov A, Kool M (2016) New brain tumor entities emerge from molecular classification of CNS-PNETs. Cell 164:1060–1072.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  5. Wesseling P, Haberler C, Huang A, Kool M, Korshunov A, Sturm D, von Hoff K (2021) CNS neuroblastoma, FOXR2-activated. In: Central Nervous System Tumours, 5th edn. WHO classification of tumour series, Lyon (France), pp 232–234

Download references


No funding.

Author information

Authors and Affiliations




ATE, and PV conducted the neuropathological examinations; ATE, PS, EUC, RS, GP, DG, and AM conducted the molecular analyses; ATE, and PV drafted the manuscript. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Arnault Tauziède-Espariat.

Ethics declarations

Ethics approval and consent to participate

This study was approved by the GHU Paris Psychiatry and Neurosciences, Sainte-Anne Hospital’s local ethic committee.

Competing interests

The authors declare that they have no conflict of interest directly related to the topic of this article.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary Information

Additional file 1.

Histopathological and molecular features of differential diagnoses of CNS neuroblastoma, FOXR2-activated.

Additional file 2: Figure 1.

Immunohistochemical and FISH analyses results of the differential diagnoses.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Tauziède-Espariat, A., Figarella-Branger, D., Métais, A. et al. CNS neuroblastoma, FOXR2-activated and its mimics: a relevant panel approach for work-up and accurate diagnosis of this rare neoplasm. acta neuropathol commun 11, 43 (2023).

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: