Dermoid and epidermoid cysts are closely related benign, cystic tumors that occur throughout the CNS. Their slow growth may result in a long history of obscure symptoms, and they may attain large size with permanent neurologic impairment before the correct diagnosis is established. The angiographic appearance does not differ from other avascular masses. Computerized tomography (CT) can suggest a correct diagnosis.
Gawler et al1 first described low absorption values in an intracranial, fat-containing dermoid cyst, as well as low absorption values in fat-containing craniopharyngiomas and teratomas. Other authors have reported both low and high absorption values in epidermoid cysts, apparently related to the nature of the contents.2
Report of a Case.—A 12-year-old girl's symptoms began approximately three years prior to this admission. At that time, she was noted to have a mild exophthalmus with no clinical evidence of hyperthyroidism; thyroid function studies showed no abnormalities. She was subsequently noted to