Diffuse astrocytoma, MYB- or MYBL-altered

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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.
  • Entrapped neurons.
  • Usu. no mitotic activity

Notes:

  • Focally angiocentric pattern may be present.

DDx

  • Normal white matter
  • Angiocentric glioma


Images

Smears


Stains

IHC

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).[1]
  • IDH1/2 wildtype.
  • H3F3A wildtype.

Prognosis

  • Excellent (

See also

References