Diffuse fibrillary astrocytoma

Discussion:

The patient went on to have a biopsy, confirming the diagnosis. 

Histology

MICROSCOPIC DESCRIPTION: 

The sections show fragments of cerebral cortex and white matter. A portion of hippocampus is included in specimen 4. In all specimens, the white matter shows moderate hypercellularity and the cortex shows prominent perineuronal secondary structuring by atypical fibrillary astrocytes. Moderate numbers of mature neurons are identified in white matter. No mitotic figures are identified. There is no microvascular proliferation and no necrosis is seen. The topoisomerase labeling index is approximately 3%.

IMMUNOHISTOCHEMISTRY:

  • GFAP positive
  • IDH-1 R132H negative (not mutated)
  • ATRX positive (not mutated)
  • MGMT positive (likely unmethylated)
  • p53 positive
  • p16 negative

 

FINAL DIAGNOSIS: 

Diffuse fibrillary astrocytoma (WHO Grade II)

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