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Sylvian fissure epidermoid cyst

Case contributed by Assoc Prof Frank Gaillard


Temporal lobe epilepsy.

Patient Data

Age: 20
Gender: Female

A right sided middle cranial fossa near-CSF-density mass / cyst is seen displacing adjacent brain. 


There is a large lobulated extra-axial mass centered at the anteromedial aspect of the right middle cranial fossa and extending into the posterior aspect of the anterior cranial fossa, measuring approximately 27 x 42 x 39mm.

It demonstrates low signal intensity on T1, high signal intensity on T2, incomplete FLAIR suppression and diffusion restriction. Minor peripheral contrast enhancement. The lesion displaces the right MCA superiorly. No midline shift. No hydrocephalus. The remainder of the brain is unremarkable.


Large right middle cranial fossa extra-axial mass consistent with an epidermoid.

Case Discussion

The key to this case is recognizing that the margins of the lesion are scalloped rather than smooth and that the density / intensity is not that of CSF, not quite. 

The key sequence in establishing the diagnosis is of course DWI. 

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Case information

rID: 30278
Published: 4th Aug 2014
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

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