1. Diffuse hemispheric glioma with H3 p.K28M (K27M) mutation: Unusual non-midline presentation of diffuse midline glioma, H3 K27M-altered?
- Author
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Donev, Kliment, Sundararajan, Vanitha, Johnson, Derek, Balan, Jagadheshwar, Chambers, Meagan, Paulson, Vera A, Scherpelz, Kathryn P, Abdullaev, Zied, Quezado, Martha, Cimino, Patrick J, Pratt, Drew, Valerio, Ediel, Alves de Castro, João Vıctor, Carraro, Dirce Maria, Torrezan, Giovana Tardin, Wolff, Beatriz Martins, Kulikowski, Leslie Domenici, Costa, Felipe D’Almeida, Aldape, Kenneth, and Ida, Cristiane M
- Abstract
Diffuse midline glioma, H3 K27-altered (DMG-H3 K27) is an aggressive group of diffuse gliomas that predominantly occurs in pediatric patients, involves midline structures, and displays loss of H3 p.K28me3 (K27me3) expression by immunohistochemistry and characteristic genetic/epigenetic profile. Rare examples of a diffuse glioma with an H3 p.K28M (K27M) mutation and without involvement of the midline structures, so-called “diffuse hemispheric glioma with H3 p.K28M (K27M) mutation” (DHG-H3 K27), have been reported. Herein, we describe 2 additional cases of radiologically confirmed DHG-H3 K27 and summarize previously reported cases. We performed histological, immunohistochemical, molecular, and DNA methylation analysis and provided clinical follow-up in both cases. Overall, DHG-H3 K27 is an unusual group of diffuse gliomas that shows similar clinical, histopathological, genomic, and epigenetic features to DMG-H3 K27 as well as enrichment for activating alterations in MAPK pathway genes. These findings suggest that DHG-H3 K27 is closely related to DMG-H3 K27 and may represent an unusual presentation of DMG-H3 K27 without apparent midline involvement and with frequent MAPK pathway activation. Detailed reports of additional cases with clinical follow-up will be important to expand our understanding of this unusual group of diffuse gliomas and to better define the clinical outcome and how to classify DHG-H3 K27.
- Published
- 2024
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