Pilocytic astrocytoma

Case contributed by Assoc Prof Frank Gaillard


Headache and cranial nerve dysfunction.

Patient Data

Age: 8 years
Gender: Male

CT brain

CT of the brain with and without contrast demonstrates a large partially cystic mass in the right cerebellar hemisphere. The solid component only minimally enhances with a focal region demonstrating more prominent ring enhancement. The fourth ventricle is effaced, and the lateral ventricles are enlarged. There is also marked effect on the brainstem with the prepontine and perimesencephalic cisterns obliterated. 


MRI brain

MRI of the brain confirms the findings on CT. A large partially cystic mass has its epicenter in the right cerebellar hemisphere, displacing and effacing the fourth ventricle, resulting in hydrocephalus (these ventricles are far too large for an 8 year old child). 

The mass has a solid component, which is nodular, and slightly hypointense on T1 compared to the cerebellum, and hyperintense on T2. It demonstrates bright contrast enhancement. 

Case Discussion

A cystic mass with mural enhancement in a child arising from the cerebellar hemisphere is usually a pilocytic astrocytoma. This patient went on to have a craniotomy and resection which confirmed the diagnosis. 

Case courtesy of Bob Cook, MD. Western Memorial Regional Hospital Corner Brook, Newfoundland.

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Case information

rID: 8474
Published: 3rd Feb 2010
Last edited: 6th Apr 2021
Inclusion in quiz mode: Included