张孟哲，高昕宇，杨镇圭，汪卫建，张勇，程敬亮

患者男，29岁，发作性头晕伴复视4月余，加重1月余。1月前至当地医院就诊，查颅脑MRI考虑为特发性炎性脱髓鞘(idiopathic inflammatory demyelinating diseases,IIDD)并给予激素冲击治疗，症状缓解。而后复视症状加重，且逐渐出现头痛难忍，头痛剧烈时伴有恶心，出现嗜睡、精神差，双下肢肌力下降等症状。遂转至本院进一步治疗。

MRI检查：左侧小脑半球、左侧桥小脑结合臂、小脑蚓部、四脑室后壁见斑片状、结节状长T1长T2信号，FLAIR序列上病变呈稍高信号，弥散加权成像(diffusion weighted imaging,DWI)呈高信号。较大者位于左侧小脑半球，体积22 mm×19 mm×14 mm。静脉注入钆喷酸葡胺(Gd-DTPA)后增强扫描:病灶均呈均匀明显强化(图1D箭)，时间信号强度曲线(time of intensity curve,TIC)呈上升型，临近软脑膜可见明显强化。然后使用磁共振波谱(magnetic resonance spectrum,MRS)来评估代谢信息，H-MRS的特征是Cho/Cr较正常侧升高(图1 A-F)。

图1 男，29岁，原发小脑伯基特淋巴瘤。A、B：轴位MR图像显示病灶主体位于左侧小脑半球(箭所指)，T1为低信号，T2为高信号。C：DWI明显弥散受限。D、E：T1加权图像增强显示病灶明显强化，时间信号强度曲线(TIC)呈上升型。F：H-MRS显示Cho/Cr升高。G：病理镜下呈“满天星”样，左小脑半球(HE×200)有中等大小的淋巴细胞。H：荧光原位杂交分析显示myc基因多拷贝Fig.1 A 29 years old male patient,primary cerebellar Burkitt lymphoma.A,B:Axial MR images showing the main bulk of the tumor was in the left cerebellar hemisphere and appeared as hypo-intensity on T1-weighted image and hyper-intensity on T2-weighted image.C:The tumor showing hyper-intensity on DWI.D,E:T1-weighted images with contrast enhancement revealing that the lesion was enhanced and time of intensity curve(TIC)was of increasing type.F:H-MRS showing increase of choline/creatine ratio.G:The tumor showing'starry-sky'appearance with medium-sized lymphocytes in left cerebellar hemisphere respectively(HE×200).H:Fluorescent in-situ hybridization analysis(c-myc dual color break apart probe,Vysis)revealing multiple copies of the myc gene.

其他相关检查：行PET-CT排除转移瘤，确定为中枢神经系统原发性病变。实验室检查显示，人类免疫缺陷病毒(human immunodeficiency virus,HIV)和EB病毒均为阴性。

病理所见：该患者接受了后颅窝开颅手术。术后病理切片显示呈“满天星”图案，可见中等大小的淋巴细胞。免疫组化分析发现病灶细胞表达CD10、CD20、CD79a和Bcl-6，不表达CD3、Bcl-2、synaptophysin、MPO、S-100蛋白。Ki-67呈明显的弥漫性核阳性，增殖指数接近100%。……