Case contributed by Dr Hani Salam


Incidental finding on MRI of the cervical spine for radicular symptoms. MRI brain for further assessment.

Patient Data

Age: Adult

Within the inferior aspect of the fourth ventricle is a mass with very high T2 signal (similar to CSF) and low T1 signal (again, similar to CSF). On FLAIR the mass does not fully attenuate, and no contrast enhancement is present. Importantly on DWI / ADC the mass demonstrates restricted diffusion. 

Despite its size, the mass does not result in hydrocephalus. It is an isolated abnormality. 

Annotated image

Annotated images

Mass within the 4th ventricle (yellow dotted line) is of low T1 signal and high T2 signal, similar to CSF. On FLAIR much of the lesion, especially peripherally (green arrow) does not fully attenuate, and this same area demonstrate high signal on DWI (red arrow). 

Case Discussion

Features are characteristic of an epidermoid cyst, albeit in an unusual location - the posterior fossa is a very common location for these lesions, however they are in most cases in the prepontine and cerebellopontine cisterns. 

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Case information

rID: 8659
Published: 21st Feb 2010
Last edited: 16th Jul 2018
Tag: brain
Inclusion in quiz mode: Included

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