Pediatric-type diffuse high-grade glioma

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The category Pediatric-type diffuse high-grade glioma contains specific brain tumours belonging into the main group of Glioma. This category consists of diffusely growing tumors observed in children and young-adults.

The fifth edition of CNS WHO classfication recognizes four distinct tumour diagnoses.


Diffuse midline glioma, H3 K27-altered

  • High-grade astrocytic neoplasm associated with midline structures (thalamus, brain stem, spinal cord).
  • Mostly in children and adolescents.
  • Includes diffuse intrinsic pontine gliomas (DPIG).
  • Newly defined entity since WHO 2016 classification.[1]
  • Distinct biological and clinical group with poor prognosis.[2]
    • EGFR amplification is usu. absent.[3]
    • Tumors usu. have unmethylated MGMT promotor.[4]
  • MRI: May be or be not enhancing.
  • Histologic spectrum ranges from minimal hypercellularity to full-blown glioblastoma.

Note: Cases may also appear outside midline structures and in adult patients.[5]

Diffuse hemispheric glioma, H3 G34-mutant

  • Diffusely infiltrating glioma in young adults and adolescents.
  • WHO CNS grade 4 neoplasm.
  • Up to 15% of all hemispheric pediatric gliomas.
  • Highly cellular tumor often with microvascular proliferation and necrosis.
  • May resemble embryonal tumours (important DDx).[6]
  • IHC: MAP2+ve, TP53+ve, Olig2-ve, ATRX loss.[7]
  • H3F3A G43R or G34V mutation present.

Diffuse pediatric-type high-grade glioma, H3-wildtype and IDH-wildtype

  • CNS WHO grade 4 tumour ocurring in children and adolescents.
  • May occur anywhere in the brain.
  • Contrast enhancing tumour.
  • Frequent alterations include TP53, PDGFRA, EGFR or MYCN.
  • Absence of IDH1/2 and H3F3a mutation.
  • Three distinct subtypes in methylation profile.

Infant-type hemispheric glioma

  • Large astrocytic tumor.
  • Median age: 2 months.
  • Supratentorial.
  • May be present before birth.
  • Well demarcated.
  • Typically with ALK, ROS1 or MET fusions.
  • Distinct methylation tumor profile.
  • Outcome in infants with ALK fusions usu. somewhat better than in older children.
  • IHC: GFAP +/-ve, Olig2+ve

See also

References

  1. Louis, DN.; Perry, A.; Reifenberger, G.; von Deimling, A.; Figarella-Branger, D.; Cavenee, WK.; Ohgaki, H.; Wiestler, OD. et al. (Jun 2016). "The 2016 World Health Organization Classification of Tumors of the Central Nervous System: a summary.". Acta Neuropathol 131 (6): 803-20. doi:10.1007/s00401-016-1545-1. PMID 27157931.
  2. Khuong-Quang, DA.; Buczkowicz, P.; Rakopoulos, P.; Liu, XY.; Fontebasso, AM.; Bouffet, E.; Bartels, U.; Albrecht, S. et al. (Sep 2012). "K27M mutation in histone H3.3 defines clinically and biologically distinct subgroups of pediatric diffuse intrinsic pontine gliomas.". Acta Neuropathol 124 (3): 439-47. doi:10.1007/s00401-012-0998-0. PMID 22661320.
  3. Meyronet, D.; Esteban-Mader, M.; Bonnet, C.; Joly, MO.; Uro-Coste, E.; Amiel-Benouaich, A.; Forest, F.; Rousselot-Denis, C. et al. (Aug 2017). "Characteristics of H3 K27M-mutant gliomas in adults.". Neuro Oncol 19 (8): 1127-1134. doi:10.1093/neuonc/now274. PMID 28201752.
  4. Banan, R.; Christians, A.; Bartels, S.; Lehmann, U.; Hartmann, C. (12 2017). "Absence of MGMT promoter methylation in diffuse midline glioma, H3 K27M-mutant.". Acta Neuropathol Commun 5 (1): 98. doi:10.1186/s40478-017-0500-2. PMID 29246238.
  5. Nakata, S.; Nobusawa, S.; Yamazaki, T.; Osawa, T.; Horiguchi, K.; Hashiba, Y.; Yaoita, H.; Matsumura, N. et al. (Jul 2017). "Histone H3 K27M mutations in adult cerebellar high-grade gliomas.". Brain Tumor Pathol 34 (3): 113-119. doi:10.1007/s10014-017-0288-6. PMID 28547652.
  6. Korshunov A, Capper D, Reuss D, Schrimpf D, Ryzhova M, Hovestadt V | display-authors=etal (2016) Histologically distinct neuroepithelial tumors with histone 3 G34 mutation are molecularly similar and comprise a single nosologic entity. Acta Neuropathol 131 (1):137-46. DOI:10.1007/s00401-015-1493-1 PMID: 26482474
  7. Wang L, Shao L, Li H, Yao K, Duan Z, Zhi C | display-authors=etal (2022) Histone H3.3 G34-mutant Diffuse Gliomas in Adults. Am J Surg Pathol 46 (2):249-257. DOI:10.1097/PAS.0000000000001781 PMID: 34352809