What do epidermoid cysts consist of pathologically?
Epidermoid cysts have a thin capsule which is made of a thin layer of squamous epithelium which macroscopically is white and pearly and may be smooth, lobulated or nodular. Internal cystic components are often filled with desquamated epithelial keratin and cholesterol crystals, grossly appearing as a creamy, waxy material.
Intracranially, where are epidermoid cysts most frequently found?
Cerebellopontine angle is the most common location accounting for 50%.
The 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 demonstrates high signal on DWI (red arrow).