Diffuse leptomeningeal glioneuronal tumour
Central Nervous System Tumours (WHO Classification, 5th ed.)
| This page is under construction |
Primary Author(s)*
Laveniya Satgunaseelan, MBBS BMedSc FRCPA, Royal Prince Alfred Hospital
WHO Classification of Disease
| Structure | Disease |
|---|---|
| Book | Central Nervous System Tumours (5th ed.) |
| Category | Gliomas, glioneuronal tumours, and neuronal tumours |
| Family | Gliomas, glioneuronal tumours, and neuronal tumours |
| Type | Glioneuronal and neuronal tumours |
| Subtype(s) | Diffuse leptomeningeal glioneuronal tumour |
Related Terminology
| Acceptable | N/A |
| Not Recommended | Disseminated oligodendroglioma-like leptomeningeal neoplasm; primary leptomeningeal oligodendrogliomatosis |
Gene Rearrangements
| Driver Gene | Fusion(s) and Common Partner Genes | Molecular Pathogenesis | Typical Chromosomal Alteration(s) | Prevalence -Common >20%, Recurrent 5-20% or Rare <5% (Disease) | Diagnostic, Prognostic, and Therapeutic Significance - D, P, T | Established Clinical Significance Per Guidelines - Yes or No (Source) | Clinical Relevance Details/Other Notes |
|---|---|---|---|---|---|---|---|
| BRAF | KIAA1549::BRAF | Tandem duplication at chr7q34 - duplication and insertion of ~2Mb fragment resulting in fusion of 5’ of KIAA1549 with 3’ of BRAF | t(7;7)(q34;q34) | Common (72%; WHO) | D, T | Yes (WHO) | Case report evidence of efficacy of BRAF inhibitors in DLGNT case harboring KIAA1549::BRAF fusion[1] |
| NTRK1/2/3 | Fusion partner not specified (PMID: 29766299) | Downstream activation of MAPK/ERK signalling pathway in CNS tumors | Not specified | Rare | D,T | Yes (WHO) | 3 cases with NTRK1/2/3 fusions[2] |
| RAF1 | TRIM33:RAF1 | Downstream activation of MAPK/ERK signalling pathway in CNS tumors | t(1;3)(p13;p25) | Rare | D | Yes (WHO) | 1 case with TRIM33::RAF1 fusion[3] |
Individual Region Genomic Gain/Loss/LOH
| Chr # | Gain, Loss, Amp, LOH | Minimal Region Cytoband and/or Genomic Coordinates [Genome Build; Size] | Relevant Gene(s) | Diagnostic, Prognostic, and Therapeutic Significance - D, P, T | Established Clinical Significance Per Guidelines - Yes or No (Source) | Clinical Relevance Details/Other Notes | |
|---|---|---|---|---|---|---|---|
| 1p | Loss | Complete arm loss (PMIDs: 22941225, 29766299) | Chr1p | Unknown | D | Yes (WHO) | Prevalence common, between 59% (by FISH; PMIDs: 22596013, 17184079, 19486008, 22941225, 25720745) and 100% (by CNV calling from DNA methylation array data[4]). |
| 1q | Gain | Complete arm gain (PMIDs: 29766299, 30465258) | Chr1q | Unknown | D | Yes (WHO) | Prevalence common, between 56% and 63% (by CNV calling from DNA methylation array data[5][6])
Found in all cases of DLGNT methylation class (MC)-2[7] |
Characteristic Chromosomal or Other Global Mutational Patterns
| Chromosomal Pattern | Molecular Pathogenesis | Prevalence -
Common >20%, Recurrent 5-20% or Rare <5% (Disease) |
Diagnostic, Prognostic, and Therapeutic Significance - D, P, T | Established Clinical Significance Per Guidelines - Yes or No (Source) | Clinical Relevance Details/Other Notes |
|---|---|---|---|---|---|
| Co-deletion of 1p and 19q | Unknown | Recurrent to common | D | Yes (WHO) | Prevalence between 18% and 33%[8][9] |
Gene Mutations (SNV/INDEL)
| Gene | Genetic Alteration | Tumor Suppressor Gene, Oncogene, Other | Prevalence -
Common >20%, Recurrent 5-20% or Rare <5% (Disease) |
Diagnostic, Prognostic, and Therapeutic Significance - D, P, T | Established Clinical Significance Per Guidelines - Yes or No (Source) | Clinical Relevance Details/Other Notes |
|---|---|---|---|---|---|---|
| BRAF | p.V600E (activating mutation) | Oncogene
|
Rare | D, T | Yes (WHO, NCCN) | Rare reports of DLGNTs harboring BRAF p.V600E mutations\[10][11], including abstracts detailing efficacy of BRAF inhibtors in BRAF-mutant DLGNT[12][13])
|
| PIK3CA | p.E545A | Oncogene
|
Rare | Nil | No | Case report of co-occurring PIK3CA variant[14] |
| TERT | Activating mutations in promoter region | Oncogene | Rare | Nil | No | Point mutations described include C228T and C228A[15] |
Note: A more extensive list of mutations can be found in cBioportal, COSMIC, and/or other databases. When applicable, gene-specific pages within the CCGA site directly link to pertinent external content.
Epigenomic Alterations
On methylation profiling of a large series of DLGNTs, two methylation classes have been defined - DLGNT methylation class (MC)-1 and DLGNT methylation class (MC)-2. All cases of DLGNT-MC-2 exhibited gain of chr1q, with 1p/19q codeletion more common in DLGNT-MC-1[16].
Genes and Main Pathways Involved
| Gene; Genetic Alteration | Pathway | Pathophysiologic Outcome |
|---|---|---|
| BRAF, FGFR1; Activating mutations | MAPK signaling | Increased cell growth and proliferation |
| FGFR1, PIK3CA; Activating mutations | PI3K–Akt signaling pathway | Increased cell growth, proliferation, survival and motility |
Genetic Diagnostic Testing Methods
- Fusion detection via targeted NGS (RNA or DNA panels) or FISH
- Chromosomal alterations can be detected by FISH, SNP array, methylation array or NGS
- Methylation profiling via CNS tumor classifiers for DLGNT-MCs
Familial Forms
One case of DLGNT in which a germline mutation in RAF1 has been documented[17].
References
- ↑ Valiakhmetova, Andge; et al. (2020-12-04). "LGG-26. DIFFUSE LEPTOMENINGEAL GLIONEURONAL TUMOR (DLGNT) IN CHILDREN: DIFFERENT CLINICAL PRESENTATIONS AND OUTCOMES". Neuro-Oncology. 22 (Supplement_3): iii371–iii371. doi:10.1093/neuonc/noaa222.408. ISSN 1522-8517. PMC 7715974 Check
|pmc=value (help). - ↑ Deng, Maximilian Y.; et al. (2018-08). "Molecularly defined diffuse leptomeningeal glioneuronal tumor (DLGNT) comprises two subgroups with distinct clinical and genetic features". Acta Neuropathologica. 136 (2): 239–253. doi:10.1007/s00401-018-1865-4. ISSN 1432-0533. PMID 29766299. Check date values in:
|date=(help) - ↑ Deng, Maximilian Y.; et al. (2018-08). "Molecularly defined diffuse leptomeningeal glioneuronal tumor (DLGNT) comprises two subgroups with distinct clinical and genetic features". Acta Neuropathologica. 136 (2): 239–253. doi:10.1007/s00401-018-1865-4. ISSN 1432-0533. PMID 29766299. Check date values in:
|date=(help) - ↑ Deng, Maximilian Y.; et al. (2018-08). "Molecularly defined diffuse leptomeningeal glioneuronal tumor (DLGNT) comprises two subgroups with distinct clinical and genetic features". Acta Neuropathologica. 136 (2): 239–253. doi:10.1007/s00401-018-1865-4. ISSN 1432-0533. PMID 29766299. Check date values in:
|date=(help) - ↑ Deng, Maximilian Y.; et al. (2018-08). "Molecularly defined diffuse leptomeningeal glioneuronal tumor (DLGNT) comprises two subgroups with distinct clinical and genetic features". Acta Neuropathologica. 136 (2): 239–253. doi:10.1007/s00401-018-1865-4. ISSN 1432-0533. PMID 29766299. Check date values in:
|date=(help) - ↑ Chiang, Jason; et al. (2019-01). "Chromosome arm 1q gain is an adverse prognostic factor in localized and diffuse leptomeningeal glioneuronal tumors with BRAF gene fusion and 1p deletion". Acta Neuropathologica. 137 (1): 179–181. doi:10.1007/s00401-018-1940-x. ISSN 1432-0533. PMID 30465258. Check date values in:
|date=(help) - ↑ Deng, Maximilian Y.; et al. (2018-08). "Molecularly defined diffuse leptomeningeal glioneuronal tumor (DLGNT) comprises two subgroups with distinct clinical and genetic features". Acta Neuropathologica. 136 (2): 239–253. doi:10.1007/s00401-018-1865-4. ISSN 1432-0533. PMID 29766299. Check date values in:
|date=(help) - ↑ Rodriguez, Fausto J.; et al. (2015-04). "High rate of concurrent BRAF-KIAA1549 gene fusion and 1p deletion in disseminated oligodendroglioma-like leptomeningeal neoplasms (DOLN)". Acta Neuropathologica. 129 (4): 609–610. doi:10.1007/s00401-015-1400-9. ISSN 1432-0533. PMC 4696044. PMID 25720745. Check date values in:
|date=(help) - ↑ Deng, Maximilian Y.; et al. (2018-08). "Molecularly defined diffuse leptomeningeal glioneuronal tumor (DLGNT) comprises two subgroups with distinct clinical and genetic features". Acta Neuropathologica. 136 (2): 239–253. doi:10.1007/s00401-018-1865-4. ISSN 1432-0533. PMID 29766299. Check date values in:
|date=(help) - ↑ Dodgshun, Andrew J.; et al. (2016-06). "Disseminated glioneuronal tumors occurring in childhood: treatment outcomes and BRAF alterations including V600E mutation". Journal of Neuro-Oncology. 128 (2): 293–302. doi:10.1007/s11060-016-2109-x. ISSN 1573-7373. PMID 26994902. Check date values in:
|date=(help) - ↑ Appay, Romain; et al. (2020-06-30). "Diffuse leptomeningeal glioneuronal tumor: a double misnomer? A report of two cases". Acta Neuropathologica Communications. 8 (1): 95. doi:10.1186/s40478-020-00978-7. ISSN 2051-5960. PMC 7325675 Check
|pmc=value (help). PMID 32605662 Check|pmid=value (help). - ↑ Valiakhmetova, Andge; et al. (2020-12-04). "LGG-26. DIFFUSE LEPTOMENINGEAL GLIONEURONAL TUMOR (DLGNT) IN CHILDREN: DIFFERENT CLINICAL PRESENTATIONS AND OUTCOMES". Neuro-Oncology. 22 (Supplement_3): iii371–iii371. doi:10.1093/neuonc/noaa222.408. ISSN 1522-8517. PMC 7715974 Check
|pmc=value (help). - ↑ Aung, Le Le (2020-12-01). "HGG-06. REMARKABLE RESPONSE TO BRAF INHIBITOR IN AN INFANT WITH DISSEMINATED DIFFUSE LEPTOMENINGEAL GLIONEURONAL TUMOR (DLGNT)". Neuro-Oncology. 22 (Supplement_3): iii345. doi:10.1093/neuonc/noaa222.297. ISSN 1522-8517. PMC 7715114 Check
|pmc=value (help). - ↑ Appay, Romain; et al. (2020-06-30). "Diffuse leptomeningeal glioneuronal tumor: a double misnomer? A report of two cases". Acta Neuropathologica Communications. 8 (1): 95. doi:10.1186/s40478-020-00978-7. ISSN 2051-5960. PMC 7325675 Check
|pmc=value (help). PMID 32605662 Check|pmid=value (help). - ↑ Deng, Maximilian Y.; et al. (2018-08). "Molecularly defined diffuse leptomeningeal glioneuronal tumor (DLGNT) comprises two subgroups with distinct clinical and genetic features". Acta Neuropathologica. 136 (2): 239–253. doi:10.1007/s00401-018-1865-4. ISSN 1432-0533. PMID 29766299. Check date values in:
|date=(help) - ↑ Deng, Maximilian Y.; et al. (2018-08). "Molecularly defined diffuse leptomeningeal glioneuronal tumor (DLGNT) comprises two subgroups with distinct clinical and genetic features". Acta Neuropathologica. 136 (2): 239–253. doi:10.1007/s00401-018-1865-4. ISSN 1432-0533. PMID 29766299. Check date values in:
|date=(help) - ↑ Dodgshun, Andrew J.; et al. (2016-06). "Disseminated glioneuronal tumors occurring in childhood: treatment outcomes and BRAF alterations including V600E mutation". Journal of Neuro-Oncology. 128 (2): 293–302. doi:10.1007/s11060-016-2109-x. ISSN 1573-7373. PMID 26994902. Check date values in:
|date=(help)