Fig. 12.

MRI of epidermoid cysts. Note that the signal of epidermoid cyst in the brain may be different from a subcutaneous. (A) The characteristic appearance of an epidermoid cyst in the cerebellopontine angle. The lesion has a similar signal intensity to cerebrospinal fluid on T2-weighted sequences. The diagnosis is confirmed on DWI which demonstrates very bright signals with intermediate ADC values similar to the brain parenchyma (DWI and ADC are not presented here). (B) Axial T1 and T2-weighted images of the lesion. There is a well-circumscribed, ovoid epidermoid cyst in the subcutaneous location. Its signals are low on T1-weighted and high signal on T2-weighted. (C) MRI in a 15-year-old female with a small size epidermal cyst in the finger. MRI shows a well-defined oval-shaped lesion with slightly high signal intensity on a T1W image and low signal intensity on a T2W image (arrow).