Abstract
A 43-year-old woman presented with ataxia and right-sided cranial nerve palsies. Ten years prior to admission, she was operated for a right cerebellopontine (CP) angle epidermoid. Computed tomography (CT) scan, using GE 9800, showed a large high-density mass without enhancement effect in the right CP angle. The density ranged between 60 and 66 Hounsfield units. Surgery revealed a recurrent epidermoid cyst containing a viscid, dark-green fluid without any cholesterol crystal or clots. Chemical analyses of the cyst content disclosed protein and lipid concentrations 25.6 g/dl and 1, 275 mg/dl, respectively. Ion chromatography revealed only a trace of metal ions. Thin layer chromatography of the lipids showed high phospholipids and low triglyceride, indicating that the high density in this case was not caused by an intratumoral hemorrhage but by desquamation of the squamous epithelium with accumulation of sloughed debris.
Two cases of high-density epidermoids subjected to protein analysis were found in the literature. From these data including the authors' it was shown that CT density correlated well with the protein concentration.
