目的 探讨颅内血管周细胞瘤(HPC)的MRI表现及其特征.方法 回顾性分析经病理证实的5例颅内HPC的临床表现、病理特征及影像表现.结果 5例颅内HPC,男3例,女2例;年龄37 ～ 60岁,均为单发病灶,4例位于小脑幕上,1例位于小脑幕下.MRI表现肿瘤呈分叶状,呈等T1,稍长T2信号,瘤体内可见囊变坏死、出血及流空血管,周围可见轻度水肿,位于小脑幕下的1例病灶可见第三脑室受压,并可见侧脑室明显扩张积水,5例病灶均表现为“窄基底”与脑膜相连.增强扫描肿块实质部分明显强化,其内及周边可见较多的血管,5例病灶均未见明显“脑膜尾征”,1例病灶侵犯颅骨,1例病灶累及静脉窦.免疫组织化学结果显示5例CD34、波形蛋白及CD99均为(+),EMA,S100,GFAP均未见表达;Ki-67标记,其中2例为＜5％表达,3例为5％ ～ 10％表达;5例Syn染色均为(-).结论 颅内HPC的MRI表现有一定的特征性,分析其特点有助于提高术前诊断的准确性.“,”Objective To investigate MRI manifestations and pathological features of intracranial hemangiopericytoma in order to make a further understanding of this tumor.Methods Clinical data,imaging findings and pathological characteristics of 5 patient with pathologically-proved intracranial hemangiopericytoma were retrospectively analyzed.Results Five cases,including three males and two females,were enrolled in this study.The patients were 37-60 years old.The tumor was single in all 5 patients.Of the 5 patients,the lesion was located above the tentorium cerebelli in 4 and under the tentorium cerebelli in one.On MRI,the lesions were lobulated in shape with long T1WI signal and long T2WI signal.Cystic degeneration,necrosis,hemorrhage as well as flow void vessels were observed within the tumor,and mild edema could be noted around the lesion.Compression of the third ventricle with the dilatation hydrocephalus of the lateral ventricle was seen in one case whose lesion was located under the tentorium cerebelli.In other 5 cases,the solid part of the lesion was obviously enhanced after the contrast agent was injected,and the blood vessel was observed in all lesions.No lesion showed the “dural tail sign”.Immunohistochemical examination showed that 5 cases had positive CD34,Vim and CD99 and negative EMA,S100,GFAP.The expression level of Ki-67 was ＜5％ in 2 cases and was 5％-10％ in 3 cases.Syn staining was negative in all 5 cases.Conclusion Intracranial hemangiopericytoma has certain MRI characteristics,which are very helpful in differentiating it from other diseases.