OBJECTIVE: Intracranial epidermoids ( @entity3540 ) mimic @entity145 in their radiologic characteristics, especially in the cerebellopontine angle. It is essential to differentiate the two conditions because they warrant different therapeutic interventions. The objective of this study is to elucidate the different radiologic characteristics of the conditions. STUDY DESIGN AND SETTING: This was a retrospective study of 4 @entity1 referred for a differential diagnosis and management of @entity1504 to the Departments of Neurotology/Neurosurgery and Neuroradiology in a tertiary referral university hospital. @entity1 : Four @entity1 of different age groups with @entity1504 , diagnosed epidermoid or @entity145 , were chosen. A retrospective analysis of their case charts, radiologic and surgical interventions, and follow-up records was undertaken. METHODS: The imaging techniques used included computerized tomographic scans, magnetic resonance imaging (MRI) with T1, T2, proton-density, and @entity2287 -enhanced T1 images. In addition, special MRI sequences were used that included fluid-attenuated inversion recovery and echo planar diffusion scanning. All the @entity1 underwent an audiovestibular evaluation. RESULTS: Both lesions are characteristically well demarcated and have a homogeneous low density, similar to cerebrospinal fluid on computerized tomographic scan, showing no contrast enhancement. On MRI, epidermoids and @entity145 usually appear hypointense on T1-weighted images and hyperintense on T2-weighted images. On fluid-attenuated inversion recovery, an @entity145 tends to follow cerebrospinal fluid intensity, whereas an epidermoid becomes hyperintense. There are occasions when an epidermoid may appear as a low-intensity lesion on fluid-attenuated inversion recovery. This dilemma is resolved with the use of echo planar diffusion scanning, on which an epidermoid remains bright. CONCLUSION: The authors recommend the use of fluid-attenuated inversion recovery and diffusion sequence MRI when definitive radiologic diagnosis of @entity1504 becomes difficult with routine computerized tomographic scanning and MRI.

Radiologic differentiation of intracranial epidermoids from XXXX .

@entity1 :: ('9606', 'Species') :: ['patients', 'PATIENTS'] @entity1504 :: ('MESH:D002561', 'Disease') :: ['cystic intracranial lesions', 'intracranial cystic lesions'] @entity3540 :: ('MESH:D002781', 'Disease') :: ['cholesteatomas'] @entity145 :: ('MESH:D016080', 'Disease') :: ['arachnoid cysts', 'arachnoid cyst'] @entity2287 :: ('MESH:D005682', 'Chemical') :: ['gadolinium']
@entity145 :: (MESH:D016080,Disease) :: ['arachnoid cysts']
