颅内黑色素瘤的MRI表现(附6例报告及文献复习)

MRI Features of Intracranial Melanoma(6 Cases Report and Literatures Review)

目的探讨颅内黑色素瘤的MRI表现,以提高对该病的认识。方法回顾性分析6例颅内黑色素瘤患者的影像学、临床及病理资料并复习相关文献。结果 1例病变位于左侧额颞叶,T_1WI呈明显高信号,T_2WI及FLAIR呈明显低信号,增强MRI呈明显均匀强化;1例病变位于右侧小脑半球,T_1WI呈稍低、低及稍高混杂信号,T_2WI呈高、稍高混杂信号,FLAIR呈等、稍高混杂信号,增强MRI呈欠均匀强化;1例病变位于左侧桥小脑角区,T_1WI呈明显高信号,T_2WI及FLAIR呈明显低信号,增强MRI呈明显均匀强化;1例病变位于左侧额顶叶,T_1WI呈等、高混杂信号,T_2WI及FLAIR呈低、稍低混杂信号,增强MRI呈环形强化。1例病变位于右侧额叶,部分囊性变,T_1WI呈高、稍高信号,T_2WI及FLAIR呈低、稍低信号,增强MRI实质部分呈明显强化;1例病变位于右顶叶,T_1WI呈等、稍低混杂信号,T_2WI及FLAIR呈等、稍高混杂信号,增强MRI呈明显欠强化。结论颅内黑色素瘤包括原发性和继发性黑色素瘤,典型性黑色素瘤MRI检查T_1WI以高信号为主,T_2WI及FLAIR以低信号,增强扫描呈均匀或较均匀明显强化;非典型黑素瘤T_1WI可呈低或等混杂信号,T_2WI及FLAIR呈高或稍高混杂信号,增强扫描可呈不均匀中度强化或呈出血MRI改变,临床识别较困难。

Objective To further explore and identify the MRI characteristics of Intracranial Melanoma.Methods MRI results,medical records and pathological results of 6 cases with intracranial melanoma who presented to our hospital for treatment between January 2006 to December 2015 were collected and retrospectively analyzed.A review of the relevant literature was then done.Results For 1 case with lesion located in the left frontal and temporal lobes,the lesion showed hyperintensity on T_1W MR imaging and hypointensity on both T_2WI and FLAIR;on contrast-enhanced MRI the lesion was markedly enhanced.For 1 case with tumor emanating from the right cerebellar hemisphere,the tumor showed slightly low,low and high signal heterogeneous intensity on T_1WI and showed slightly high and high signal heterogeneous intensity on T_2WI and isointensity and slightly high signal heterogeneous intensity on FLAIR;a marked and heterogeneous enhancement of tumor was observed on contrast-enhanced MRI.One mass lesion originating from the left cerebellopontine angle region showed hyperintensity on T_1W MR imaging and hypointensity on both T_2WI and FLAIR;on contrast-enhanced MRI,the mass was markedly enhanced.One tumor located in the left cerebral frontal and parietal lobes showed isointensity and hyperintensity on T_1WI as well as low and slightly low signal heterogeneous intensity on both T_2WI and FLAIR;a ring-like enhancement was displayed on contrast-enhanced MRI.One tumor located on right frontal lobe,with a partial cystic component,showed high and slightly high signal heterogeneous intensity on T_1WI,with a low and slightly low signal heterogeneous intensity on both T_2WI and FLAIR;A marked enhancement of tumor solid component was shown on contrast-enhanced MRI.One lesion arising from the right parietal lobe showed isointensity and slight heterogeneous hypointensity on T_1WI,isointensity and slight heterogeneous hyperintensity on both T_2WI and FLAIR;Amarked enhancement was displayed on contrastenhanced MRI.Conclusion For typical intracranial melanoma,the mass mainly shows hyperintensity on T_1W MR imaging and hypointensity on both T_2W and FLAIR MR imaging.On contrast-enhanced MRI the lesion was markedly enhanced.However for atypical intracranial melanomas,the mass mainly shows hypointensity on T_1W MR imaging and hyperintensity on T_2W MR imaging;frequently a moderate heterogeneous enhancement of the mass could be shown on contrast-enhanced MRI.Sometimes its appearance on MRI is remarkably affected by intralesional hemorrhage,which leads to difficulty in identification and recognizing intracranial melanoma on imaging.