Retro-cerebellar arachnoid cyst

Case contributed by Dr Amr Farouk


50 year old presenting with headache

Patient Data

Age: 50 year old
Gender: Male

A large right retro-cerebellar extra-axial cyst is seen compressing the right cerebellar hemisphere and elevating the tentorium being insinuated between the occipital lobes.It is seen following CSF signal on all sequences with facilitated diffusion. It is seen measuring 3.2X7.7X6.5 cm along its axial and cranio-caudal dimensions.

Annotated image showing the membrane of the arachnoid cyst (red arrows). Remodelling of the skull is also present (blue arrow head). 

Postoperative status after shunt tube placement within the aforementioned cystic lesion seen running along the posterior surface of right cerebellar hemisphere. (cystoperitoneal shunt tube)


Xray images following the course of the cystoperitoneal shunt tube seen extending from posterior cranial fossa down to the pelvic cavity. No evidence of shunt break or dislodgement could be detected.

Case Discussion

This case illustrates typical features of an arachnoid cyst, with visualization of the cyst membrane and bone remodelling.Also, it shows cysto-peritoneal shunting which is a therapeutic option for treatment of symptomatic arachnoid cyst.

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Case information

rID: 57448
Published: 26th Dec 2017
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

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