title: Intracranial meningeal melanocytoma: CT and MRI.
abstract: We report the MRI and CT findings of an intracranial meningeal melanocytoma (IMM) arising from Meckel's cave and review the imaging characteristics of IMM. On CT, IMM constantly appear as well-circumscribed, isodense to slightly dense, extra-axial tumours with homogeneous contrast enhancement. This appearance is non-specific and similar to that of meningiomas or small neuromas. On MRI, the signal of IMM is strongly related to the amount of melanin pigment: the more melanin, the more shortening of T1 and T2 relaxation times. Only when it shows as a homogeneous mass, bright on T1 and dark on T2 weighting, can a specific diagnosis of a melanin-containing tumour be made. However, this still cannot provide a distinction between IMM and malignant meningeal melanoma.
authors.affiliation: Department of Diagnostic Radiology, Chang Gung Memorial Hospital, Taipei, Taiwan.
authors.forename: C J
authors.initials: CJ
authors.lastname: Chen
authors.forename: Y I
authors.initials: YI
authors.lastname: Hsu
authors.forename: Y S
authors.initials: YS
authors.lastname: Ho
authors.forename: Y H
authors.initials: YH
authors.lastname: Hsu
authors.forename: L J
authors.initials: LJ
authors.lastname: Wang
authors.forename: Y C
authors.initials: YC
authors.lastname: Wong
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008544:Melanocytes / Q000473:pathology; D008545:Melanoma / Q000175:diagnosis; D008577:Meningeal Neoplasms / Q000175:diagnosis* / Q000453:epidemiology; D008579:Meningioma / Q000175:diagnosis* / Q000453:epidemiology; D014057:Tomography, X-Ray Computed