CT and MRI Findings of Extracranial Meningioma

Purpose:The aim of the study was to evaluate the CT and MRI characteristics of extracranial meningioma.Methods:A retrospective review was made in 6 patients with extracranial meningiomas:2 cases were examed with mere CT examination,1 with mere MRI examination,and 3 with both.Results: Extracranial meningioma was identified in the facial space in 4 cases(3 cases in the parapharyngeal space,and 1 in the masticator space) and in the orbit in 2 cases.The plain CT images showed that all lesions were mostly round soft tissue masses.Calcification was found in 3 of 5 cases.In the plain MRI, all lesions were revealed with iso - intensity signal on T_1 WI and uneven hyper - intensity signal on T_2 WI ("pepper and salt" sign).All masses were obviously enhanced on post - contrasted images.The external carotid artery was displaced by extracranial meningioma in parapharyngeal space in 2 cases,and was encompassed in 1 case.Four of 6 extracranial meningiomas were found lesions with cranial involvement. The patterns of bone erosion(5 cases) by the lesions were identified as thickening in 4 cases and absorption in 1 case.Conclusion:CT and MRI findings of the extracranial meningioma are characterized by a soft tissue mass with calcification,"pepper and salt" sign,and involvement of adjacent bones.It is believed that CT and MRI examination may provide valuable information for the differential diagnosis.