·臨床醫(yī)學(xué)圖像·

室管膜下巨細(xì)胞星形細(xì)胞瘤

圖1 女性，13歲，主因視力下降1個(gè)月入院，頭部MRI顯示右側(cè)側(cè)腦室室間孔區(qū)占位性病變。予腫瘤切除術(shù)。術(shù)后病理證實(shí)室管膜下巨細(xì)胞星形細(xì)胞瘤1a橫斷面CT顯示，右側(cè)側(cè)腦室室間孔區(qū)實(shí)性占位性病變，呈等密度，病變前部可見(jiàn)結(jié)節(jié)樣高密度鈣化影（箭頭所示）；左側(cè)側(cè)腦室室壁點(diǎn)狀高密度影，為鈣化的室管膜結(jié)節(jié)；雙側(cè)側(cè)腦室明顯擴(kuò)張1b橫斷面T1WI顯示，病灶呈不均勻等信號(hào)，其內(nèi)可見(jiàn)斑片樣低信號(hào)影（箭頭所示）；左側(cè)側(cè)腦室點(diǎn)狀室管膜結(jié)節(jié)呈等信號(hào)1c橫斷面T2WI顯示，病灶呈稍高信號(hào)，其內(nèi)可見(jiàn)小片狀囊性變區(qū)域，呈高信號(hào)（箭頭所示）1d橫斷面增強(qiáng)T1WI顯示，病變呈明顯不均勻強(qiáng)化（箭頭所示）1e正中矢狀位增強(qiáng)T1WI顯示，右側(cè)側(cè)腦室室間孔區(qū)不均勻強(qiáng)化影（箭頭所示），側(cè)腦室擴(kuò)張明顯，胼胝體干抬高Figure 1A 13?year?old girl was hospitalized because of vision loss for one month.Head MRI showed a solid occupying lesion located in interventricular foramen of right lateral ventricle.The lesion was totally removed and postoperative pathological diagnosis revealed SEGA.Axial CT showed an iso?density solid lesion in the interventriculesr foramen of right lateral ventricle with a high?density calcification located in anterior of the lesion(arrow indicates).A punctiform high?density calcified subependymal nodule was found on the wall of left lateral ventricle,and bilateral lateral ventricles were enlarged(Panel 1a).Axial T1WI revealed an uneven iso?intensity lesion with patchy low?intensity inside it(arrow indicates).The punctiform subependymal nodule was iso?intensity(Panel 1b).Axial T2WI revealed slight high?intensity lesion with small high?intensity cystic areas(arrow indicates,Panel 1c).Axial enhanced T1WI showed heterogeneous enhancement(arrow indicates,Panel 1d).Median sagittal enhanced T1WI showed heterogeneous enhancement(arrow indicates)in interventricular foramen of enlarged right lateral ventricle.The corpus callosum was lifted upwards(Panel 1e).1e

室管膜下巨細(xì)胞星形細(xì)胞瘤（SEGA）是臨床少見(jiàn)的生長(zhǎng)緩慢的神經(jīng)上皮組織腫瘤，屬WHOⅠ級(jí)，僅占原發(fā)性中樞神經(jīng)系統(tǒng)腫瘤的0.1%，好發(fā)于20歲以下兒童和青少年、偶見(jiàn)于成人，男性多于女性，多發(fā)生于結(jié)節(jié)性硬化癥（TSC）患者。腫瘤好發(fā)于側(cè)腦室室間孔區(qū)，第三和第四腦室及基底節(jié)區(qū)少見(jiàn)，典型者可堵塞室間孔致梗阻性腦積水。CT呈等密度，強(qiáng)度不均勻，多合并低密度小囊性變區(qū)域，病灶邊緣和內(nèi)部常見(jiàn)斑片樣或結(jié)節(jié)樣鈣化（圖1a）。MRI顯示腫瘤實(shí)性部分呈T1WI等或略低信號(hào)（圖1b），T2WI等或略高信號(hào)，多合并小囊性變（圖1c），DWI呈等信號(hào)，鈣化不明顯，病灶內(nèi)出血罕見(jiàn)；增強(qiáng)掃描病灶呈明顯不均勻強(qiáng)化（圖1d，1e）。結(jié)節(jié)性硬化癥患者除合并室間孔區(qū)室管膜下巨細(xì)胞星形細(xì)胞瘤外，多合并室管膜下結(jié)節(jié)及皮質(zhì)和（或）皮質(zhì)下錯(cuò)構(gòu)瘤樣結(jié)節(jié)。室管膜下結(jié)節(jié)在CT上表現(xiàn)為側(cè)腦室室壁室管膜下散在突向側(cè)腦室的結(jié)節(jié)影，呈等或稍低密度，可見(jiàn)鈣化或僅表現(xiàn)為鈣化（圖1a）；在MRI上呈T1WI等或高信號(hào)（圖1b）、T2WI等或低信號(hào)、DWI等信號(hào)，增強(qiáng)掃描病灶無(wú)明顯強(qiáng)化。CT和磁敏感加權(quán)成像（SWI）能夠提示微小室管膜下結(jié)節(jié)。位于室間孔區(qū)以及動(dòng)態(tài)隨訪中體積增大且明顯強(qiáng)化的室管膜下結(jié)節(jié)均提示轉(zhuǎn)化為室管膜下巨細(xì)胞星形細(xì)胞瘤的可能。皮質(zhì)和（或）皮質(zhì)下結(jié)節(jié)及類(lèi)錯(cuò)構(gòu)瘤樣腦白質(zhì)異常在MRI上呈T1WI等或略低信號(hào)、T2WI等或略高信號(hào)，增強(qiáng)掃描多無(wú)明顯強(qiáng)化；腦白質(zhì)異常表現(xiàn)為白質(zhì)區(qū)楔形和線(xiàn)樣自皮質(zhì)指向側(cè)腦室室壁的長(zhǎng)T2信號(hào)。典型的室管膜下巨細(xì)胞星形細(xì)胞瘤較易診斷，而不伴結(jié)節(jié)性硬化癥典型癥狀者應(yīng)注意與好發(fā)于腦室系統(tǒng)的腫瘤相鑒別，如中樞神經(jīng)細(xì)胞瘤、脈絡(luò)膜乳頭狀瘤和室管膜瘤等。

（天津市環(huán)湖醫(yī)院神經(jīng)放射科韓彤供稿）

Subependymal giant cell astrocytoma

HAN Tong
Department of Neuroradiology,Tianjin Huanhu Hospital,Tianjin 300350,China(Email:mrbold@163.com)

10.3969/j.issn.1672?6731.2017.04.015