幕下孤立性纤维瘤的影像学表现(附5例报道及文献复习)

Imaging features of subtentorial solitary fibrous tumor:A literature review of 5 cases

目的:探讨幕下孤立性纤维瘤(solitary fibrous tumor,SFT)的影像学表现,以提高其诊断准确率。方法:回顾性分析5例经手术病理证实的幕下SFT的影像及临床、病理资料,1例行CT平扫,3例行MRI平扫及增强检查,1例仅行MRI增强检查。结果:本组5例(4例女性,1例男性)均为单发病灶,均宽基底与脑膜相连,2例位于右侧小脑半球,1例位于左侧小脑半球凸面,1例跨右侧小脑幕上下生长,1例位于左侧桥小脑角区,肿瘤最大径范围约4.1~5.2 cm,5例边界均清楚,4例呈浅分叶状,1例呈类圆形。肿瘤CT平扫呈稍高密度,MRI T1WI呈等信号或稍低信号,T2WI呈稍高信号或低信号,3例T2WI病灶内见片状低信号区,2例病灶内见囊变,2例病灶内见迂曲血管,4例病灶周围可见轻度水肿,3例病灶周围见脑脊液环绕征象。增强扫描实性成分及囊壁均明显强化,2例可见脑膜尾征。结论:幕下SFT影像学表现具有一定的特征性,当幕下肿块呈浅分叶状并具有脑外肿瘤的征象,CT上呈稍高密度,T1WI呈等或稍低信号,T2WI呈稍高信号或低信号,明显强化,T2WI病灶内见低信号区及迂曲血管影时,可考虑诊断该病,但最终确诊仍需依靠病理及免疫组织化学检查。

Objective To summarize the imaging features of subtentorial solitary fibrous tumor,in order to improve its diagnostic accuracy. Methods ： Imaging manifestations and clinicopathological data of 5 subtentorial solitary fibrous tumor confirmed by operation and pathology were analyzed retrospectively. There were CT plain scan in one case, MRI plain and enhancement scan in three cases,only MRI enhancement scan in one case. Results： All of the 5 cases （4 fe-males,1 male） were dural based single lesion, the lesions were located in right hemisphere （n = 2 ） , left cerebellum convex （n = 1） , across supratentorial and infratentorial （ n = 1） and left cerebellar pontine angle （ n = 1）. The maxi-mum diameter of tumor is approximately 4. 1 ？ 5. 2 cm , the boundary of 5 cases was clear, 4 cases were multilobular and 1 case was round. The tumor showed slightly high density on plain CT scan, isointense or slightly hypointense sig-nal on T1WI , slightly hyperintense signal or hypointense signal on T2WI. There were hypointense signals area in 3 ca-ses on T2WI,cystic portion in 2 cases,flow void vascular signals in 2 cases,mild edema around tumor in 4 cases and cerebrospinal fluid surrounded tumor in 3 cases. The solid and the wall of cystic of tumor were enhanced obviously, dural tail was found in 2 cases. Conclusion ： Imaging manifestation of subtentorial solitary fibrous tumor has its own features. If the subtentorial mass showed multilobular and signs of extracerebral tumors, slightly high density on plain CT scan, isointense or slightly hypointense signal on T1WI and slightly hyperintense signal or hypointense signal on T2WI,obvious enhancement,flow void vascular and low signal area, diagnosis of subtentorial solitary fibrous tumor could be considered. But its confirmation still depends on histopathology and immunohistochemistry.