Diffuse astrocytoma, MYB- or MYBL-altered
| Diffuse astrocytoma, MYB- or MYBL-altered | |
|---|---|
| Diagnosis in short | |
 Diffuse astrocytoma, MYB- or MYBL-altered H&E stain. | |
| LM DDx | Angiocentric glioma |
| IHC | GFAP +ve |
| Gross | soft, unencapsulated |
| Site | brain - usu. temporal |
|
| |
| Prevalence | common - esp. in children |
| Prognosis | good (WHO Grade I) |
Diffuse astrocytoma, MYB- or MYBL-altered is a low-grade, often pediatric-onset astrocytoma. It is very rare.
General
- CNS WHO grade 1.
- Entity introduced in 2021. [1]
- Rare epilepsy-associated tumor.
- Median time to surgery often exceeds more than 10 years.
- No sex predilection.
Imaging
- T1 hypointense.
- Non-enhancing.
- Occasionally large cysts.
Gross
- Soft, unencapsulated.
- Grey to white.
Microscopic
Features:
- Diffusely growing.
- Minimal incereased cell density.
- Monomorphic, bland glial cells.
- Entrapped neurons.
- Usu. no mitotic activity
Notes:
- Focally angiocentric pattern may be present.
DDx
- Normal white matter
- Angiocentric glioma
Images
H&E
Stains
Features:
- GFAP +ve.
- Olig2 -ve.
- MAP2 -ve.
- CD34 -ve.
- ATRX retained.
Molecular
- Structural variant of MYB or MYBL1 (most common fusion partners: MAML2, MMP16 , PCDGHA1).[2]
- IDH1/2 wildtype.
- H3F3A wildtype.
Prognosis
- Excellent (most cases are stable after surgery).
See also
References
- ↑ "The 2021 WHO Classification of Tumors of the Central Nervous System: An update on pediatric low-grade gliomas and glioneuronal tumors". Brain Pathol: e13060. February 2022. doi:10.1111/bpa.13060. PMID 35218102.
- ↑ "Genetic alterations in uncommon low-grade neuroepithelial tumors: BRAF, FGFR1, and MYB mutations occur at high frequency and align with morphology". Acta Neuropathol 131 (6): 833–45. June 2016. doi:10.1007/s00401-016-1539-z. PMC 4866893. PMID 26810070. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4866893/.