颅内原发淋巴瘤的MRI诊断与病理分析

目的 探讨颅内原发淋巴瘤的MRI特征及病理学表现,以提高对该病的诊断准确性.方法 回顾性分析28例经病理证实的颅内原发淋巴瘤的MRI表现及病理特点.所有病例均行MRI平扫及扩散加权成像(DWI)扫描,19例平扫后行MRI增强扫描.结果 MRI表现:(1)单发型,颅内单发病灶,好发于近中线区的深部脑组织或脑表面;(2)多发型Ⅱa型(区域分布型),病变局部可见一较大病灶,周边可见数个或多个小病灶,病灶呈区域性分布;Ⅱb型(弥漫分布型),颅内多发病灶,散在分布,无明显区域性.病灶呈团块状、分叶状或形态不规则,T1 WI多呈稍低或等信号,T2 WI呈等、稍高或稍低信号,DWI呈高信号;增强扫描病灶多明显强化,可见"握拳征"、"脐凹症"、"尖突征"、"蝶翼征"、"星芒状毛刺征"、"梳齿征".病理:弥漫一致的瘤细胞呈浸润生长,血管周围明显,细胞体积大,核仁明显,周围见小淋巴细胞散在分布.免疫组化:CD20、CD79 a阳性,GFAP阴性.结论 颅内原发淋巴瘤的MRI表现多样,具有一定的特征性,仔细分析可提高其诊断准确性,确诊仍需病理及免疫组化.

MRI performances and pathological findings of primary intracranial lymphoma

Objective To investigate the MRI features and pathological findings of primary intracranial lymphoma and to improve the diagnostic accuracy.Methods MRI features and pathological findings were analyzed in 28 pathologically proved cases of primary intracranial lymphoma.All 28 cases were examined by MRI scanning and diffusion weighted imaging(DWI),among which 19 cases were examined by enhanced MRI scanning.Results MRI manifestations:(1)single type:intracranial single lesion,the most common site was nearly the middle area of deep brain or brain surface;(2)multiple type.Type Ⅱa:multiple lesions in regional distribution, often showed several small lesions around a larger lesion.Type Ⅱb:multiple lesions in diffused distribution,often showed scattered distribution without an obvious regional distribution.The shapes of lesion were mass-like,nodular or irregular.The lesions showed isointense or slightly hypointense on T1 WI,and isointense,slightly hyperintense or slightly hypointense on T2 WI.On DWI,the le-sions showed hyperintense.Most lesions showed obvious enhancement with "fisting sign","incision sign","pointed sign","butterfly sign","long and stiff spicule sign"and "comb sign".Pathology:the tumor cells were heteromorphic and spread around the vessels, and showed greater cellularity,big prominent nucleoli,and small lymphocytes.The immunohistochemical examination showed that all tumor cells were positive for CD20 and CD79a and negative for GFAP.Conclusion The MRI findings of primary intracranial lym-phoma are various.Careful analysis can improve the diagnostic accuracy of the disease,definitive diagnosis requires histopathological and immunohistochemical examinations.