Intracranial dermoid cyst mimicking hemorrhage. Case report and review of the literature.

Intracranial dermoid cysts are rare congenital lesions that result from abnormal sequestration of ectodermal cells during neural tube formation. Dermoid cysts are typically hypodense on computed tomography, but when hyperdense may mimic a hemorrhage. The authors report the case of a 16-year-old boy who presented with a history of chronic progressive headaches. Findings on a CT scan were indicative of hemorrhage. Magnetic resonance imaging revealed the lesion to be a dermoid cyst with unusual characteristics. Upon gross resection, the lesion appeared to be a dermoid cyst without hemorrhage, but histological evaluation revealed evidence of hemorrhage. The authors describe their experience and review the literature, emphasizing that a dermoid cyst may have unusual radiographic characteristics indicative of hemorrhage and may contain areas of hemorrhage on histological examination.