[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [General pathology](https://durgical.com/en/general-pathology/) › [Central nervous system](https://durgical.com/en/general-pathology/areas/cns/) › Adult diffuse gliomas

# Adult diffuse gliomas

- Lesion

Diffuse gliomas grow into normal brain like roots; glioblastoma, the worst, shows dead zones lined by crowded tumour cells and new vessels.

Updated Nov 12, 2026

## Key points

- Glioblastoma, IDH-wildtype, CNS WHO grade 4: necrosis with pseudopalisading tumour cells and microvascular (glomeruloid) proliferation; or grade 4 by molecular features (EGFR amplification, TERT promoter mutation, gain of chromosome 7 with loss of 10).
- Butterfly glioma: glioblastoma crossing the corpus callosum.
- Astrocytoma, IDH-mutant: IDH1 R132H, ATRX loss and TP53 mutation; grades 2 to 4; CDKN2A/B deletion raises the grade to 4.
- Oligodendroglioma: round nuclei with perinuclear halos (fried-egg cells), chicken-wire capillaries and calcification; IDH mutation plus 1p/19q codeletion.
- MGMT promoter methylation predicts better response to alkylating chemotherapy.

## What it is

Diffuse gliomas are the most frequent primary malignant brain tumours of adults. They infiltrate surrounding brain, so complete removal is impossible. Molecular features define the three main types: astrocytoma IDH-mutant (younger adults, slower), oligodendroglioma IDH-mutant with 1p/19q codeletion (best outlook, sensitive to chemotherapy), and glioblastoma IDH-wildtype (older adults, aggressive). The IDH mutation produces 2-hydroxyglutarate, an oncometabolite that changes DNA methylation.

## Step by step

- A glial progenitor acquires an early driver: IDH mutation, or in glioblastoma, EGFR and TERT changes.
- IDH-mutant cells make 2-hydroxyglutarate, which blocks enzymes and causes a hypermethylated genome.
- Further hits (TP53, ATRX, or 1p/19q loss) define the lineage.
- Tumour cells migrate along white matter tracts and vessels.
- Hypoxia in fast growth causes necrosis; surviving cells palisade and secrete VEGF.
- VEGF drives glomeruloid microvascular proliferation and edema.

## Adult diffuse gliomas compared

| Feature | Astrocytoma, IDH-mutant | Oligodendroglioma | Glioblastoma, IDH-wildtype |
| --- | --- | --- | --- |
| Age | Young adults | Adults, middle age | Older adults |
| Key genes | IDH1/2, ATRX loss, TP53 | IDH1/2, 1p/19q codeletion, TERT promoter | EGFR amplification, TERT promoter, +7/−10, PTEN |
| Histology | Infiltrating astrocytic cells, hyperchromatic nuclei | Round nuclei with halos, delicate branching capillaries, calcium | Pleomorphic cells, mitoses, pseudopalisading necrosis, microvascular proliferation |
| Grades | 2, 3 or 4 | 2 or 3 | 4 |
| [Outlook](https://durgical.com/en/conditions/glioblastoma/) | Years; can progress to grade 4 | Best of the three | Median survival about a year and a half with treatment |

## Markers

- IDH1 R132H
- ATRX
- p53
- GFAP
- OLIG2
- Ki-67
- MGMT promoter methylation
- 1p/19q codeletion (FISH or sequencing)

## Clinical notes

- New seizures in an adult, headaches or progressive focal deficit; MRI shows a ring-enhancing mass with necrosis in glioblastoma.
- Oligodendrogliomas often present with seizures and show calcification on CT.

## Memory aid

IDH means a younger, slower tumour; add 1p/19q and you have an oligo; no IDH plus necrosis means glioblastoma.

## Test yourself

Think of the answer, then tap the question to see it.

## What two microscopic features define glioblastoma?

Necrosis with pseudopalisading tumour cells and microvascular (glomeruloid) proliferation.

## Which molecular change defines oligodendroglioma together with IDH mutation?

Codeletion of chromosome arms 1p and 19q.

## What does IDH-mutant protein produce?

The oncometabolite 2-hydroxyglutarate, which inhibits DNA and histone demethylases.

## Why is MGMT promoter methylation tested in glioblastoma?

Methylation silences a DNA repair enzyme and predicts a better response to alkylating chemotherapy.

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[More Pathology questions →](https://durgical.com/en/practice/?f=pathology)

## Elsewhere in DurgiPedia

- [Glial cells: astrocytes, oligodendrocytes, microglia, Schwann cells](https://durgical.com/en/histology/glial-cells-astrocytes-oligodendrocytes-microglia-schwann-cells/)

## Connections

## Related 9

- [CNS tumours: an overview](https://durgical.com/en/general-pathology/cns-tumours-an-overview/)
- [Pilocytic astrocytoma](https://durgical.com/en/general-pathology/pilocytic-astrocytoma/)
- [Familial tumour syndromes of the nervous system](https://durgical.com/en/general-pathology/familial-tumour-syndromes-of-the-nervous-system/)
- [Tumour angiogenesis](https://durgical.com/en/general-pathology/tumour-angiogenesis/)
- [Patterns of necrosis: coagulative, liquefactive, caseous, fat, fibrinoid, gangrenous](https://durgical.com/en/general-pathology/patterns-of-necrosis-coagulative-liquefactive-caseous-fat-fibrinoid-gangrenous/)
- [Molecular pathology: PCR, FISH, sequencing and liquid biopsy](https://durgical.com/en/general-pathology/molecular-pathology-pcr-fish-sequencing-and-liquid-biopsy/)
- [Oncogenes: RAS, MYC, HER2, BCR-ABL and the table to know](https://durgical.com/en/general-pathology/oncogenes-ras-myc-her2-bcr-abl-and-the-table-to-know/)
- [Tumour suppressor genes: RB, TP53, APC, BRCA and the two-hit hypothesis](https://durgical.com/en/general-pathology/tumour-suppressor-genes-rb-tp53-apc-brca-and-the-two-hit-hypothesis/)
- [Translocations, amplifications and epigenetic changes in cancer](https://durgical.com/en/general-pathology/translocations-amplifications-and-epigenetic-changes-in-cancer/)

## Related conditions 3

- [Glioblastoma](https://durgical.com/en/conditions/glioblastoma/)
- [Epilepsy and seizures](https://durgical.com/en/conditions/epilepsy-and-seizures/)
- [Raised intracranial pressure and brain herniation](https://durgical.com/en/conditions/raised-intracranial-pressure-and-brain-herniation/)

[← All of general pathology](https://durgical.com/en/general-pathology/)

Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Glioblastoma Multiforme](https://www.ncbi.nlm.nih.gov/books/NBK558954/) (StatPearls (NCBI Bookshelf), 2026); [Central Nervous System Tumors Treatment (PDQ®)–Health Professional Version](https://www.cancer.gov/types/brain/hp/adult-brain-treatment-pdq) (National Cancer Institute, 2026).

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Source: https://durgical.com/en/general-pathology/adult-diffuse-gliomas/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/general-pathology/adult-diffuse-gliomas/