Epidermoid cyst

Case contributed by Dr Ammar Haouimi



Patient Data

Age: 9 years
Gender: Male

A well-defined extra-axial ovoid lesion at the base of the right frontal lobe. It appears inhomogeneous and hypointense on T1 and FLAIR, and T2-hyperintense with no enhancement seen on post-contrast T1. The DWI shows restricted diffusion.

Case Discussion

Differential diagnosis includes arachnoid cyst. On MRI, both epidermoid and arachnoid cysts usually have the same signal intensity on T1 and T2 (low T1 and high T2). On FLAIR sequence, an arachnoid cyst tends to follow the signal intensity of the CSF, whereas an epidermoid shows a high signal. Sometimes an epidermoid cyst may demonstrate a low signal intensity on FLAIR sequences (as in this case). The use of DWI resolves this dilemma, on which an epidermoid remains bright (restricted diffusion) whereas an arachnoid cyst follows the CSF signal intensity.

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Case information

rID: 60122
Published: 12th May 2018
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included
Institution: Aurès Medical Imaging Center - Batna Algeria

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