Dense cerebellopontine epidermoid cyst.

A diffuse, bubblelike, high-density epidermoid cyst of the cerebellopontine angle is described as seen on CT scanning. The high density was attributed to high protein concentration of the cystic fluid due to a proliferative and exudative defense reaction to a "minor leak" of the lipidic material through the capsule, verified by Sudan black B stain. A description of the appearance of the tumor on computerized tomography, based on 42 cases of intracranial epidermoids reported in the literature, is discussed. To our knowledge this is the first morphological documentation of spontaneous leakage of cyst contents, and the second report in the English literature of a dense intracranial epidermoid.