Low-grade gemistocytic morphology in H3 G34R-mutant gliomas and concurrent K27M mutation: Clinicopathologic findings

Meaghan Morris, Meghan Driscoll, John W. Henson, Charles Cobbs, Li Qun Jiang, Christopher D. Gocke, Liam Chen, Fausto J. Rodriguez

Research output: Contribution to journalArticlepeer-review

Abstract

Mutations in histone H3 are key molecular drivers of pediatric and young adult high-grade gliomas. Histone H3 G34R mutations occur in hemispheric high-grade gliomas and H3 K27M mutations occur in aggressive, though histologically diverse, midline gliomas. Here, we report 2 rare cases of histologically low-grade gliomas with gemistocytic morphology and sequencing-confirmed histone H3 G34R mutations. One case is a histologically low-grade gemistocytic astrocytoma with a G34R-mutation in H3F3A. The second case is a histologically low-grade gemistocytic astrocytoma with co-occurring K27M and G34R mutations in HIST1H3B. Review of prior histone H3-mutant gliomas sequenced at our institution shows a divergent clinical and immunohistochemical pattern in the 2 cases. The first case is similar to prior histone H3 G34Rmutant tumors, while the second case most closely resembles prior histone H3 K27M-mutant gliomas. These represent novel cases of sequencing-confirmed histone H3 G34R-mutant gliomas with low-grade histology and add to the known rare cases of G34R-mutant tumors with gemistocytic morphology. Although K27M and G34R mutations are thought to be mutually exclusive, we document combined K27M and G34R mutations in HIST1H3B and present evidence suggesting the K27M-mutation drove tumor phenotype in this dual mutant glioma.

Original languageEnglish (US)
Pages (from-to)1038-1043
Number of pages6
JournalJournal of Neuropathology and Experimental Neurology
Volume79
Issue number10
DOIs
StatePublished - 2021
Externally publishedYes

Keywords

  • G34R
  • Gemistocytic
  • H3F3A
  • HIST1H3B
  • Histone H3
  • K27M
  • Low-grade glioma

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Neurology
  • Clinical Neurology
  • Cellular and Molecular Neuroscience

Fingerprint

Dive into the research topics of 'Low-grade gemistocytic morphology in H3 G34R-mutant gliomas and concurrent K27M mutation: Clinicopathologic findings'. Together they form a unique fingerprint.

Cite this