Difference between revisions of "Diffuse astrocytoma, MYB- or MYBL-altered"

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'''Diffuse astrocytoma, MYB- or MYBL-altered''' is a low-grade pediatric [[astrocytoma]]. It is very rare.
'''Diffuse astrocytoma, MYB- or MYBL-altered''' is a low-grade, often pediatric-onset [[astrocytoma]]. It is very rare.


==General==
==General==
*
* CNS WHO grade 1.
* Rare epilepsy-associated tumor.
* No sex predilection.


==Imaging==
==Imaging==
* T1 hypointense.
* Non-enhancing.
* Occasionally large cysts.


==Gross==
==Gross==
* Soft, unencapsulated.
* Grey to white.


==Microscopic==
Features:
* Diffusely growing.
* Minimal incereased cell density.
* Monomorphic, bland glial cells.
*


==Microscopic==
Features:<ref name=Ref_PSNP82-4>{{Ref PSNP|82-4}}</ref>
*Classically biphasic (though either may be absent):
*#Fibrillar.
*#Microcystic/loose.
*Hair-like fibres ~ 1 micrometer; ''pilo-'' = hair.<ref>URL: [http://dictionary.reference.com/browse/pilo- http://dictionary.reference.com/browse/pilo-]. Accessed on: 24 November 2010.</ref>
**Best seen on smear or with GFAP [[IHC]].
*Rosenthal fibres - '''key feature'''.
**May be rare.  Not pathognomonic (see below).
*Eosinophilic granular bodies.
*Low cellularity - when compared to medulloblastoma and ependymoma.


Notes:  
Notes:  

Revision as of 07:31, 4 April 2022

Diffuse astrocytoma, MYB- or MYBL-altered
Diagnosis in short
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.
  • Rare epilepsy-associated tumor.
  • 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.


Notes:

  • +/-Microvascular proliferation.
  • +/-Focal necrosis.
    • Necrosis with pseudopalisading more likely glioblastoma.
  • +/-Mitoses - not significant in the context of the Dx.

DDx

  • Normal white matter
  • Angiocentric glioma


Images

Smears


Stains

IHC

Features:

  • GFAP +ve (fibres).


Molecular

Prognosis

  • Excellent (

See also

References

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