Epidermoid cysts are cysts lined by squamous epithelium that contain keratin, cellular debris, and cholesterol[^3]. Unlike classic tumors, which exhibit exponential growth, epidermoid cysts, like normal skin, exhibit linear growth[^4].
Epidemiology
Epidermoid cysts account for approximately 1 % of all intracranial tumors[^2] and approximately 7 % of all Tumors in the Cerebellopontine angle. The most common age at initial diagnosis is approximately 40 years, and there is no difference in prevalence between men and women[^1].
Imaging
On MRI imaging, epidermoid cysts appear similar to Cerebrospinal fluid on T1- and T2-weighted sequences. The DWI sequence can be used to reliably distinguish them from Arachnoid cysts, as epidermoid cysts show diffusion restriction.
T1 sequence | T1 sequence with contrast enhancement | T2 sequence | DWI |
Hypointense | No contrast enhancement | Hyperintense | Diffusion restriction / hyperintense |
