Updates on the Pathologic Diagnosis of Brain Tumors in Children

Updates on the Pathologic Diagnosis of Brain Tumors in Children.

WHO CNS 5 th edition. WHO Classification of Tumours Editorial Board. World Health Organization Classification of Tumours of the Central Nervous System. 5th ed. Lyon: International Agency for Research on Cancer; 2021..

Objective. To be familiar with the histopathologic and molecular basis in the classification of the following tumors in the WHO CNS 5 th ed: Medulloblastomas Ependymomas Pediatric-type astrocytomas.

Audio Recording Oct 5, 2022 at 11:58:40 PM. CNS Tumor Diagnostics.

ARTICLE doi:10.1038/nature26000 DNA methylation-based classification of central nervous system tumours A list of authors and their affiliations appears in the online version of the paper..

Methylation Classes. a 1 CHGL MB, G3 2 GBM, RTK Ill 2 GBM, MID MB, G4 1 DLGNT 2 ENB, A 2 ENB, B CNS NB, FOXR2 GBM, RTK II 1 LGG, DIG/DIA 2 EPN, PF A Reference cohort (91 ETMR MB, WNT 2 MB G3 2 MB G4 MB: SHH CHLAD 2 MB, SHH INF 2 ATRT, MYC 2 ATRT, SHH 2 ATRT, TYR 2 CNS NB, FOXR2 5 HGNET, BCOR DMG, K27 2 GBM, G34 2 GBM, MES 2 GBM, RTKI 2 GBM, RTK II 2 GBM, MYCN 1 LIPN 1 LGG, DIG/DIA 1 LGG, DNT 1 LGG, RGNT 1 RETB 2 PGG, nc 4 LGG, GG 1 CPH, ADM PAP 1 PITAD, ACH 1 PITAD, FSH LH — 1 PITAD, PHL 1 PITAD, STHSPA 1 PITAD, TSH 2 PITAD, STH DNS A 2 PITAD, STH DNS B 1 EPN, RELA 2 EPN, YAP 2 2 EPN, SPINE 4 EPN, MPE 4 SUBEPN, PF 4 SUBEPN, SPINE 4 SUBEPN, ST Relation to WHO entities classes) 1 LGG, SEGA 2 LGG, PA PF 2 LGG, PA MID 5 HGNET, MNI 4 LGG, MYB 4 LGG, PA/GG ST 1 SCHW 1 SCHW, MEL 2 prpR A 2 pTpR B PIN T,' B 4 PINT, PBA PIN T, PPT CHORDM EWS 4 MNG 3 SFT HMPC t-SNE dimensionality (2,801 samples) PITAD STH DNS B MB, WNT DNS PRL FSH LH — 5 ANA PA 5 IHG 3 TSH ST H spA' ADENOPIT ENB, A ENB, B RETB A IDH A IDH, HG PINT, PBA p B T, PPT PINEAL CPH, ADM Q CPH, PAP CHORDM SFT PGG, nC PITUI, scn, GCT O IDH PLEX, AD PLEX, PEDA PLEX, PED B PTPR, B 8 0 5 EFT, CIC 1 MELAN 1 MELCYT 3 PLEX, AD 3 PLEX, PED A 3 PLEX, PED B 3 A IDH 3 A IDH, HG 3 0 IDH 1 LYMPHO 1 PLASMA ADENOPIT WM CEBM HEMI HYPTHAL INFLAM PINEAL PONS HMPC INFLAM SCHW CHGL EFT, 2 9 LGG, PA MID MELCYT HMB DMG, PLASMA. MELAN LYMPHO ANA PA GBM RTKI GBM, MYCN GBM, MIDÆ GBM, MES LGG, PA PF 5 J LGG, RGNT EPN, YAP LGG, DNT Control SUBEPN, ST EPN, MPE EPN, SPINE EPN, SUBEPN, PF GBM, RTKIII S GBM, G34 HGNET, MNI 2 SCHW, MEL 3 SUBEPN, SPINE LGG, MYB 4 5 IHG LGG, PAIGG ST 6 7 LGG, GG 8 DLGNT LGG, SEGA 9 10 Control REACT HGNET, BCOR CEBM MB, SHH LIPN • MB, SHH INF EPN, PF A ETMR 1 Equivalent 3 Not (combining grades) 2 Sutx:lass 4 Not (cornbining entites) 5 Not by WHO.

DNA Methylation Profiling. Infinium@ MethylationEPIC BeadChip Affordable methylome analysis meets cutting edge content. Highlights Unique Combination of Coding Region and Enhancer- Wide Coverage Over 850,000 methylation sites per sample at single- nucleotide resolution High Assay Reproducibility > 98% reproducibility for technical replicates Simple Workflow PCR-free protocol with the powerful Infinium HD Assay Compatible with FFPE Samples Protocol available for methylation studies on FFPE samples Introduction DNA methylation plays an important and dynamic role in regulating gene expression. It allows cells to acquire and maintain a specialized Figure I : The Infinium MethYationEPlC BeadChip—The Infinium MethylationEPlC BeadChip features > 850,000 CpGs in enhancer regions, gene bodies, gromoters, and CPG islands..

www.molecular neuropathology.org. www.molecular neuropathology.org.

Medulloblastoma. Medulloblastomas, molecularly defined Medulloblastoma, WNT-activated Medulloblastoma, SHH-activated and TP53-wildtype Medulloblastoma, SHH-activated and TP53-mutant Medulloblastoma, non-WNT/non-SHH Medulloblastomas, histologically defined Medulloblastoma, histologically defined.

Medulloblastoma, histologically defined. medullo tissue 1.

Molecular subgroups of medulloblastoma. WNT SHH Group 3 Group 4.

Medulloblastoma, molecularly defined. WNT 10-15% of MB Older children Favorable prognosis in children SHH 30% of MB Infants and adolescents / adults (>16 years old) Intermediate prognosis in TP53 wt 76% 5 years OS) Poor prognosis in TP53 mutant (41% 5 year OS) Non WNT / non SHH (group 3 and group 4) - worst prognosis.

MB subtyping by IHC. IV)-8 L8VD HHS-UOU/LNM-UOU HHS INM LdVA.

Gene expression profiling. Group C Group D CodeSet WIFI TNC GADI DKK2 PDLlM3 EYAI HHIP ATOHI SFRPI IMPG2 GERAS NRL MAB21L2 NPR3 KCNAI EOMES KHDRBS2 RBM24 UNC5D OASI 0 1-0.

Methylation profiling. a 1 CHGL MB, G3 2 GBM, RTK Ill 2 GBM, MID MB, G4 1 DLGNT 2 ENB, A 2 ENB, B CNS NB, FOXR2 GBM, RTK II 1 LGG, DIG/DIA 2 EPN, PF A Reference cohort (91 ETMR MB, WNT 2 MB G3 2 MB G4 MB: SHH CHLAD 2 MB, SHH INF 2 ATRT, MYC 2 ATRT, SHH 2 ATRT, TYR 2 CNS NB, FOXR2 5 HGNET, BCOR DMG, K27 2 GBM, G34 2 GBM, MES 2 GBM, RTKI 2 GBM, RTK II 2 GBM, MYCN 1 LIPN 1 LGG, DIG/DIA 1 LGG, DNT 1 LGG, RGNT 1 RETB 2 PGG, nc 4 LGG, GG 1 CPH, ADM PAP 1 PITAD, ACH 1 PITAD, FSH LH — 1 PITAD, PHL 1 PITAD, STHSPA 1 PITAD, TSH 2 PITAD, STH DNS A 2 PITAD, STH DNS B 1 EPN, RELA 2 EPN, YAP 2 2 EPN, SPINE 4 EPN, MPE 4 SUBEPN, PF 4 SUBEPN, SPINE 4 SUBEPN, ST Relation to WHO entities classes) 1 LGG, SEGA 2 LGG, PA PF 2 LGG, PA MID 5 HGNET, MNI 4 LGG, MYB 4 LGG, PA/GG ST 1 SCHW 1 SCHW, MEL 2 prpR A 2 pTpR B PIN T,' B 4 PINT, PBA PIN T, PPT CHORDM EWS 4 MNG 3 SFT HMPC t-SNE dimensionality (2,801 samples) PITAD STH DNS B MB, WNT DNS PRL FSH LH — 5 ANA PA 5 IHG 3 TSH ST H spA' ADENOPIT ENB, A ENB, B RETB A IDH A IDH, HG PINT, PBA p B T, PPT PINEAL CPH, ADM Q CPH, PAP CHORDM SFT PGG, nC PITUI, scn, GCT O IDH PLEX, AD PLEX, PEDA PLEX, PED B PTPR, B 8 0 5 EFT, CIC 1 MELAN 1 MELCYT 3 PLEX, AD 3 PLEX, PED A 3 PLEX, PED B 3 A IDH 3 A IDH, HG 3 0 IDH 1 LYMPHO 1 PLASMA ADENOPIT WM CEBM HEMI HYPTHAL INFLAM PINEAL PONS HMPC INFLAM SCHW CHGL EFT, 2 9 LGG, PA MID MELCYT HMB DMG, PLASMA. MELAN LYMPHO ANA PA GBM RTKI GBM, MYCN GBM, MIDÆ GBM, MES LGG, PA PF 5 J LGG, RGNT EPN, YAP LGG, DNT Control SUBEPN, ST EPN, MPE EPN, SPINE EPN, SUBEPN, PF GBM, RTKIII S GBM, G34 HGNET, MNI 2 SCHW, MEL 3 SUBEPN, SPINE LGG, MYB 4 5 IHG LGG, PAIGG ST 6 7 LGG, GG 8 DLGNT LGG, SEGA 9 10 Control REACT HGNET, BCOR CEBM MB, SHH LIPN • MB, SHH INF EPN, PF A ETMR 1 Equivalent 3 Not (combining grades) 2 Sutx:lass 4 Not (cornbining entites) 5 Not by WHO.

Audio Recording Oct 6, 2022 at 12:13:01 AM. Audio Recording Oct 6, 2022 at 12:14:24 AM.

Ependymomas. Supratentorial ependymoma Supratentorial ependymoma, ZFTA fusion-positive Supratentorial ependymoma, YAPI fusion-positive Posterior fossa ependymoma Posterior fossa group A (PFA) ependymoma Posterior fossa group B (PFB) ependymoma Spinal ependymoma Spinal ependymoma, MYCN-ampfified Myxopapillary ependymoma Subependymoma.

Ependymomas. Age Molecular Sex CNS WHO grade features Outcome o ST-SE ST-YAPI PF-SE SP-SE sp_Ep SP-MP 2/3 2/3 2/3 2/3 1 2/3 2 Balanced genome ZETA fusions Chromothripsis CDKN2A and/or CDKN2B loss YAPI fusions Balanced genome EZHIP mutations H3 p.K28M (K27M) mutations Chr. Iq gain Chromosomal instability Chr. 6q deletion NF2 mutations Chromosomal instability MYCN amplification (Chr. 2").

Supratentorial ependymoma – diagnostic criteria. ZFTA fusion.

ZFTA fusion – positive ihc for p65 & L1 CAM. $0..

Posterior fossa ependymoma – diagnostic criteria.

Loss of H3K27me3 in PFA. 8dd Nd3 . M•oot VdCNd3. Panwalkar P. Acta Neuropathol . 2017.

Spinal ependymoma , MYCN amplified. Essential: Spinal tumour with morphological and immunohistochemical features of ependymoma AND MYCN amplification Desirable: DNA methylation profile aligned with spinal ependymoma, MYCN-amplified High-grade histopathological features.

Astrocytoma histology. A picture containing standing, frisbee, field, water Description automatically generated.

Audio Recording Oct 6, 2022 at 12:16:00 AM. Pediatric type glioma vs adult type.

Diffuse midline glioma, H3 K27 altered. Diagram Description automatically generated.

Diffuse midline glioma, H3K27 altered. H&E. K27 mutant protein.

Diffuse hemispheric glioma, H3 G34 mutant. i*Cs•.

Diffuse pediatric- type high grade glioma, H3- wild type and IDH-wild type.

Infant-type hemispheric glioma. Cellular astrocytoma AND Presentation in early childhood AND Cerebral hemispheric location AND Presence of a typical receptor tyrosine kinase abnormality (e.g. fusion in an NTRK family gene or in ROSI , METI , or ALK) OR Methylation profile aligned with infant-type hemispheric glioma.

Pediatric-type low grade gliomas. Diffuse astrocytoma, MYB- or MYBL1 altered (WHO grade 1) Angiocentric glioma – MYB fusion (WHO grade 1) Polymorphous low-grade neuroepithelial tumor of the young (PLNTY) – FGFR2 fusion, BRAF V600E Diffuse low-grade glioma, MAPK pathway altered – look for mutations by NGS -FGFR1 duplicated or mutated -BRAF V600E mutant.

Molecular testing in pediatric brain tumors. Considering radiotherapy as an option in young children Small biopsy uncertain for low vs high grade glioma Growing tumor where there is potential for targeted therapy NTRK fusion BRAF V600E Other BFAF V600E positive tumors: Some pilocytic astrocytomas Pleomorphic xanthoastrocytomas gangliogiomas IDH1 ihc negative in adolescents / young adult.

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