title: Intracranial epidermoid cyst including elements of old hematoma.
abstract: A 70-year-old female presented with symptoms of right-sided trigeminal neuralgia. Computed tomography showed a high-density mass in the prepontine cistern without enhancement. Magnetic resonance (MR) imaging showed the mass as heterogeneous with variable but largely high-signal intensity on T1-weighted images and low-signal intensity on T2-weighted images. At surgery, the lesion was found to be an epidermoid cyst filled with old blood and lipid debris. The high-signal intensity on the T1-weighted images may reflect lipid or methemoglobin with the low intensity on T2-weighted images representing hemosiderin. Most intracranial epidermoid cysts appear as low-intensity lesions on T1-weighted images and high-signal intensity on T2-weighted images. Typical MR imaging findings are neither specific for nor constant with epidermoid cysts, requiring critical differential diagnosis.
authors.affiliation: Department of Neurosurgery, Ibaraki Seinan Medical Center Hospital.
authors.forename: H
authors.initials: H
authors.lastname: Tsurushima
authors.forename: T
authors.initials: T
authors.lastname: Kamezaki
authors.forename: Y
authors.initials: Y
authors.lastname: Tomono
authors.forename: T
authors.initials: T
authors.lastname: Nose
mesh_terms: D000368:Aged; D001927:Brain Diseases / Q000000981:diagnostic imaging / Q000473:pathology*; D004814:Epidermal Cyst / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006406:Hematoma / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D014057:Tomography, X-Ray Computed