MRI features of pleomorphic xanthoastrocytoma defined by DNA methylation profile - 05/06/25

Doi : 10.1016/j.neurol.2025.04.009

R. Fawaz ^a,⁎ , O. Aboubakr ^b, F.N. El Sissy ^c, B. Mathon ^b, B.M. Oumoussa ^d, B. Barka ^e, E. Mandonnet ^f, D. Leclercq ^a, M. Touat ^g, K. Hoang-Xuan ^g, H. Adle-Biassette ^c, F. Bielle ^e, L. Nichelli ^a
^a Department of Neuroradiology, Pitié-Salpêtrière hospital, AP–HP, 75013 Paris, France
^b Department of Neurosurgery, Hôpitaux Universitaires La Pitié Salpêtrière - Charles Foix, AP–HP, Sorbonne Université, 75013 Paris, France
^c Department of Pathology, Lariboisiere hospital, AP–HP, 75010 Paris, France
^d Inserm, UMS Production et Analyse des données en Sciences de la vie et en Santé, PASS, Plateforme Post-génomique de la Pitié-Salpêtrière, Sorbonne Université, 75013 Paris, France
^e Department of Neuropathology, Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Hôpitaux Universitaires La Pitié Salpêtrière - Charles Foix, AP–HP, Sorbonne Université, 75013 Paris, France
^f Department of Neurosurgery, Lariboisiere hospital, AP–HP, 75010 Paris, France
^g Department of Neuro-oncology, Pitié-Salpêtrière hospital, AP–HP, 75013 Paris, France

^*Corresponding author. Department of Neuroradiology, Pitié-Salpêtrière hospital, AP–HP, 75013 Paris, France.Department of Neuroradiology, Pitié-Salpêtrière hospital, AP–HPParis75013France

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Highlights

•	The absence of peritumoral edema and hypercellularity, distinguishes mcPXA group from other groups.
•	Overall survival was longer in the mcPXA group, despite the use of the same first-line treatment.
•	We propose an integrated score for PXA diagnosis, with a specificity of 95% and a sensitivity of 77%.

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Abstract

Introduction

Pleomorphic xanthoastrocytomas (PXA) are primary brain tumors challenging to diagnose due to their morphological and molecular overlap with other tumors. While DNA methylation profiling (MP) aids pathological classification, it alone may be inconclusive. Magnetic resonance imaging (MRI), routinely performed for lesion assessment, provides valuable information. Combining histo-molecular features, MP, and MRI is thus beneficial, particularly in cases of diagnostic uncertainty. In this study, we retrospectively analyzed MRI features of methylation-confirmed PXAs (mcPXAs) versus tumors with PXA-like histology using WHO 2021 criteria.

Methods

We included 29 adult patients with tumors displaying PXA-suggestive histology, completed MP, and preoperative MRI. Tumors were classified into three groups: mcPXA, histological PXA with methylation-confirmed glioblastoma (mcGBM), and other MP-confirmed diagnoses (mcMimic). Clinical and molecular data were recorded.

Results

All tumors were supratentorial with heterogeneous enhancement. The mcGBM group showed significantly more peritumoral edema and hypercellularity than mcPXA (P=0.002 and P=0.023). No significant differences were found in tumor location, cystic components, or hemorrhagic content. The BRAF^V600E mutation appeared in 89% of mcPXA, 8% of mcGBM, and 29% of mcMimic cases (P<0.05). Our composite MRI and molecular score for PXA diagnosis achieved an area under the curve of 0.95, with 95% specificity and 77% sensitivity.

Conclusion

In cases of histological uncertainty, lack of peritumoral edema and hypercellularity supports a PXA epigenetic profile. Our specific score could aid in challenging cases, though further validation in larger cohorts is warranted.

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Keywords : Pleomorphic xanthoastrocytoma, Methylation profiling, MRI, Epithelioid glioblastoma

Abbreviations : CNS, GBM, ITSS, MP, MRI, PFS, PXA