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Epidermoid Cyst

Last Updated: March 27, 2020

Figure 1: A low density lesion in the left cerebellopontine angle on CT (top row left) could represent a number of lesions including arachnoid cyst or epidermoid cyst. T2WI (top row right) and T1WI post contrast (middle row left) give little additional diagnostic information, with the lesion still matching CSF signal. FLAIR imaging (middle row right), as in this case, often demonstrates an epidermoid cyst to have different signal than CSF. Diffusion weighted imaging (bottom) is the most helpful sequence with these lesions, demonstrating often dramatic hyperintensity.