Pilocytic astrocytoma

Case contributed by Dr Bruno Di Muzio


Pregnant lady with increasing headaches.

Patient Data

Age: 25 years
Gender: Female

MRI Brain

Non-contrast T1, T2 and FLAIR volumetric acquisition through the brain. There is a 4 cm T2 hyperintense midline cerebellar mass which distorts the fourth ventricle and medulla without significant hydrocephalus but resulting in crowding of foramen magnum with mild cerebellar tonsillar herniation. 

Case Discussion

The patient went on to have a resection. 


Sections show a variably cellular tumor with a prominent microcystic architecture. Tumor cells
demonstrate elongated oval nuclei with inconspicuous nucleoli set within a fibrillary stroma. Frequent Rosenthal fibers and eosinophilic granular bodies are seen. There are focal aggregates of thin-walled, hyalinised blood vessels with the adjacent parenchyma containing hemosiderin deposition. No mitoses, necrosis or microvascular proliferation are identified.


  • GFAP: Positive
  • IDH-l R132H: Negative (non-mutated)
  • ATRX: Positive (non-mutated)
  • p53: Positive
  • BRAF V60oE: Negative
  • Topoisomerase labeling index: Approximately 1-2%.

FINAL DIAGNOSIS: Pilocytic astrocytoma (WHO Grade I).

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Case information

rID: 58110
Published: 15th Jun 2018
Last edited: 23rd Nov 2019
Inclusion in quiz mode: Included

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