Pediatric-type diffuse low-grade glioma

From Libre Pathology
Jump to navigation Jump to search

The category Pediatric-type diffuse low-grade glioma contains diffusely-growing brain tumours with specific molecular alterations belonging into the main group of Glioma. This category consists of mostly CNS WHO grade 1 tumors, observed in children and young-adults.

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

Polymorphous low-grade tumor of the young (PLNTY)

  • Since 2021 official WHO entity.[1]
  • Abbreviated PLNTY.
  • Epilepsy-associated.
  • Oligodendroglioma-like histologic features.
  • Frequently CD34+ve.[2]
  • FGFR3-TACC3 and FGFR2-CTNNA3 fusions.

Diffuse low-grade glioma, MAPK pathway-altered

  • Since 2021 official WHO entity.[1]
  • Astrocytic or oligodendroglial morphology.
  • Mostly in the cerebral hemispheres.
  • Commonly associated with epilepsy.
  • Olig2-ve, GFAP variable, CD34 mostly absent.
  • IDH and HF3FA mutations and CDKN2A deletions not compatible with this diagnosis.
  • Mutations in BRAF (V600E), FGFR1 or duplication in FGFR1 TKD.