毛细胞型星形细胞瘤MRI表现及5例误诊分析

The MRI manifestations and misdiagnostic analysis of 5 cases intracranial pilocvtic astrocytoma

目的探讨脑内毛细胞型星形细胞瘤的MRI表现及误诊原因。方法对经手术病理证实的5例脑内毛细胞型星形细胞瘤的临床资料及MRI表现进行回顾性分析。结果 5例病灶分别位于小脑后上方、左侧小脑半球、左侧颞顶枕叶三角区,T2WI像表现为混杂高信号,T1WI像表现为混杂低信号,DWI(扩散加权成像)呈混杂低信号,FLAIR(液体衰减反转恢复序列)为稍低混杂信号,增强后病灶壁结节呈明显强化,囊性部分不强化。其中4例位于小脑半球,术前误诊为髓母细胞瘤或血管母细胞瘤,1例位于左侧颞顶枕叶三角区,术前误诊为脑膜瘤或室管膜瘤。结论脑内毛细胞型星形细胞瘤较少见,MRI有特征性表现,MRI扫描有助于本病的确诊及鉴别诊断。

Abstract： Objective To explore the MRI imaging manifestations and to analyze the reasons of misdiagnosis of intracranial pilocytic astrocytoma. Methods The clinical data and MRI manifestations of 5 cases with intracranial pilocytic astrocytoma confirmed by pathology were retrospectively analyzed. Results Five ca ses were respectively located in lateral and superior of the cerebellum, left cerebellum the left trigonum ar ea of lobus timporalis, lobus parietalis and lobus occipitalis. The lesions often showed slight mixture hy perintensity on MR T2 weighted imaging （T2WI） and mixture hypointyensity on MR T1 weighted imaging （TIWI）, and hypointyensity on MR DWI and on MR FLAIR. The lesions exhibited marked enhancement in nodulus of the wall, non-enhancement showed at the cystic lesions. 4 cases which lesion located intraen cephalon were misdiagnosed as medulloblastoma and haemangioblastoma before operation, 1 case which le sion located extraencephalon was misdiagnosed as meningioma and ependymal. Conclusion Intracranial pilocytic astrocytoma is rare and prone to be misdiagnosed, the final diagnosis could be made by MRI accord- ing to their MRI characteristical manifestations.