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Reddy & Baugnon

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Fig. 20. Meningoceles mimicking sinonasal polyposis. ( A ) Coronal CT sinus image of a patient imaged for headache shows bilateral polypoid masses in the nasal cavity, with the appearance of sinonasal polyposis. However, note the defects along the adjacent posterior ethmoid roof ( ar rows ). MR imaging was therefore recommended. Sagittal T1w ( B ) and Coronal T2w MR images ( C ) showing hernia tion of gliotic brain tissue and CSF into the nasal cavity, compatible with bilateral meningoencephaloceles ( arrows ).

Fig. 21. Cholesteatoma mimicking meningocele. A 21-year-old man with bilateral hearing loss. ( A , B ). Axial and cor onal temporal bone CT shows right-sided soft tissue mass with erosion of the tegmen posteriorly ( arrows ). Note also the sclerotic underpneumatized mastoid and the left-sided middle ear and mastoid soft tissue mass. ( C , D ) Coronal T2w and T1w postcontrast fat-saturated sequences showing the right-sided mass to be T2 hyperintense and T1 hypo intense with peripheral enhancement ( arrows ). Note the thinning of the tegmen, but without inferior herniation or tethering of brain parenchyma ( thick arrow in C ). ( E ) Axial diffusion-weighted sequences showing diffusion restric tion within the mastoid and middle ear masses bilaterally, compatible with cholesteatoma ( arrows ).

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