腫瘤樣脫髓鞘病變影像特征以及鑒別診斷

1、腫瘤樣脫髓鞘病變（Tumefactive demyelinating lesions ，TDLs ） 影像特征以及鑒別診斷,,,MRI增強,中樞神經(jīng)系統(tǒng)原發(fā)性炎性脫髓鞘病,特點：以神經(jīng)纖維脫髓鞘及小血管周圍炎性細胞浸潤為主要病理表現(xiàn)的一組疾病典型表現(xiàn)為白質(zhì)內(nèi)多發(fā)、彌散的異常信號，病灶通常無明顯占位效應包括多發(fā)性硬化視神經(jīng)脊髓炎急性播散性腦脊髓炎等,,腫瘤樣脫髓鞘性病變(Tumefactive demyelinati

2、ng lesions ，TDLs）,但一些非典型病例，表現(xiàn)為占位性腫塊的脫髓鞘性病變，從臨床、影像學甚至病理學冰凍切片都很難與中樞神經(jīng)系統(tǒng)腫瘤如膠質(zhì)瘤、淋巴瘤等鑒別,Tumefactive demyelinating lesions,1979年，Van Dor Velden首次對該病進行了報告。關(guān)于這種臨床綜合癥是否屬于一種獨立的疾病仍然存在爭論，目前歸類為多發(fā)性硬化和急性播散性腦脊髓炎之間的獨立中間型。腫瘤樣炎性脫髓鞘性病變(

3、tumor-like inflammatory demyelinating diseases,TIDD）腫瘤樣脫髓鞘病變(tumor-like masses of demyelination) 脫髓鞘假瘤(demyelinating pseudotumor lesion)、假瘤樣脫髓鞘病(pseudotumor formus of demyelinating disease,臨床表現(xiàn),該病多為單時相，對激素治療敏感平均年齡33

4、-36歲，可急性、亞急性或慢性起病，以急性起病多見，隨病程延長，病情逐漸趨于穩(wěn)定 與多發(fā)性硬化不同，其病情無緩解及復發(fā)交替的特點；不發(fā)生于感染或接種疫苗后,實驗室檢查,常規(guī)及腦脊液檢查大多正常。少數(shù)低熱患者可有白細胞升高和腦脊液蛋白含量升高；腦脊液白細胞可升高,病理表現(xiàn),急性期或亞急性期的主要病理改變神經(jīng)髓鞘的破壞 ,而神經(jīng)軸索保留完好。光鏡下可見大量淋巴細胞在血管周圍呈袖套狀浸潤 ,而髓鞘破壞區(qū)則以大量單核細胞和泡沫狀巨噬

5、細胞浸潤為主、同時伴有較多的肥胖型星形細胞增生。病變區(qū)內(nèi)還可見出血或壞死。 隨著病程延長，巨噬細胞和肥胖型星形細胞逐漸減少 ,纖維型星形細胞明顯增生 ,病變開始趨于穩(wěn)定，此時無論病理或影像學均易誤診為纖維型星形細胞瘤。,影像表現(xiàn),一般為CNS白質(zhì)內(nèi)孤立病灶（大于2cm），少數(shù)多發(fā)；Kepes 統(tǒng)計孤立病灶占77．4％(24／31)，多發(fā)病例占22．6％(7／31)病灶分布以腦室旁白質(zhì)為主，單發(fā)腫塊樣病變,圓形或不規(guī)則形 ,灶周水

6、腫程度輕至中度 腫塊體積與占位效應不成比例,CT表現(xiàn),急性或亞急性起病者多表現(xiàn)為低密度 ,少數(shù)呈等密度或高密度，密度均勻或不均；伴急性出血時低密度灶內(nèi)可見片樣高密度區(qū)；伴壞死、囊變時可見局灶性更低密度區(qū)；如病變區(qū)尚保留有正常腦組織或新舊病灶重疊,則可表現(xiàn)為低、等混雜密度。慢性起病者可表現(xiàn)為低、 等或高密度，水腫程度及占位效應比急性起病者更不明顯。增強掃描病變多呈彌漫性強化或環(huán)形強化，少數(shù)不強化,MRI表現(xiàn),多表現(xiàn)為均勻長 T

7、1 、 長 T2信號 ,合并出血時呈短 T1 、 長 T1 混雜信號，有囊變時呈不均勻長 T1 、 長 T2 信號。急性起病者增強掃描多表現(xiàn)為彌漫性強化；隨著病灶中心壞死和周圍出現(xiàn)新病灶 ,則表現(xiàn)為環(huán)形強化非閉合性環(huán)行強化(open—ring sign）(77%)，口朝向皮質(zhì)，灰質(zhì)側(cè)不強化。強化環(huán)代表脫髓鞘的前緣，因此通常面對白質(zhì)。,NEUROLOGY,2007,A previously healthy 31-year-old

8、woman presented with a 2-week history of progressive left hemiparesis.,,21-year-old woman presenting with new-onset seizure and biopsy-proven tumefactive demyelinating lesion.,,垂直脫髓鞘征(Dowsons fingers）有垂直于側(cè)腦室表面的傾向；在矢狀位、冠狀

9、位腦室旁病灶可以觀察到，病灶可以呈條索狀、火焰狀，長軸垂直于側(cè)腦室也有閉合性增強,Multiple Sclerosis – Dawson’s,Fingers,,Mechi等 認為具有強化效應的病灶是新的活動性病灶，而環(huán)形強化則提示病灶病程小于1個月。同時有強化和非強化兩種病灶時，表示病灶處于不同時期，或者脫髓鞘病灶在不斷的發(fā)生,,新鮮病灶在DWI上呈輕中度高信號，但低于急性腦梗死病灶，一般高于腫瘤T2序列或SW影像上病變中心可見

10、擴張血管樣結(jié)構(gòu)走行，意味著向擴張室管膜下靜脈引流 MRS可能對于診斷有幫助，MRS顯示谷氨酸鹽和谷氨酰胺峰，這在高等級的膠質(zhì)瘤是看不到,小靜脈，腫瘤樣波譜，胼胝體累及,,,提示TDLs影像征象,相對特異性的征象腫塊體積與占位效應不成比例非閉合性環(huán)狀強化病灶中心擴張小靜脈激素治療有效非特異性征象胼胝體侵犯彌散增強類腫瘤樣MRS,激素治療后好轉(zhuǎn),50-year-old man presenting with slurre

11、d speech and biopsy-proven tumefactive demyelinating lesion,2 months after corticosteroid therapy,鑒別診斷,單發(fā)多見，往往 80％以上誤診為膠質(zhì)瘤而行手術(shù)膠質(zhì)瘤淋巴瘤膿腫多發(fā)性腫瘤樣脫髓鞘病多發(fā)性硬化、急性播散性腦脊髓炎Balo病同心圓硬化轉(zhuǎn)移瘤淋巴瘤鑒別,與腫瘤鑒別-膠質(zhì)瘤 淋巴瘤,臨床表現(xiàn)比腫瘤明顯MRI強化的區(qū)

12、域CT上呈低密度是區(qū)別淋巴瘤或膠質(zhì)瘤鑒別診斷特征之一；膠質(zhì)瘤等或低密度，淋巴瘤一般等或高密度；DWI均勻略高信號，CT等高密度，基本可以排除TDLs，,TDLs非閉合性增強是鑒別診斷的依據(jù)之一；非脫鞘病(炎癥、腫瘤等)只有7%出現(xiàn)非閉合性環(huán)形增強TDLs水腫程度及占位效應相對較輕 Distinguishing Tumefactive Demyelinating Lesions from Glioma or Centra

13、l Nervous System Lymphoma: Added Value of Unenhanced CT Compared with Conventional Contrast-enhanced MR Imaging Radiology 2009,251（2）：467-484,,TDLs,MR imaging and CT findings in 30-year-old woman with TDL. A, Axial T2-w

14、eighted and, B, con- trast-enhanced axial T1-weighted MR images show a round mass with complete rim enhancement and perilesional edema in left frontal white matter. The signal intensity of the rim is isointense to gray m

15、atter on the T2-weighted image (arrow). C, Unenhanced axial CT image shows hypoattenuation (grade 1) of the rim; the margin of the enhanced rim on the MR image is not discernible on unenhanced CT image.,膠母,MR imaging and

16、 CT findings in 54-year-old woman with glioblastoma. A, Axial T2-weighted and, B, contrast-enhanced axial T1-weighted MR images show a round cystic mass with complete rim enhancement and peritumoral edema in the subcort

17、ical white matter of the right frontal lobe. The signal intensity of the rim is isointense to gray matter on the T2-weighted image (arrow). C, Unenhanced axial CT image demonstrates isoattenuation (grade 2) of the rim (a

18、rrowhead).,TDLs,膠母,Glioblastoma Multiforme: no dark line of advancing demyelination,膠母,TDL,MR imaging and CT findings in 32-year-old man with TDL. A, Axial T2-weighted and, B, contrast- enhanced axial T1-weighted MR ima

19、ges demonstrate white matter lesions with heterogeneous enhancement in the parietal lobe and corpus callosum. The signal intensity of the enhancing components of the right parietal lobe is mixed (isointense plus hyperin

20、tense) on the T2-weighted image. C,Unenhanced axial CT image shows hypoattenuation (grade 1) of both the enhanced and unenhanced components of the lesions (arrows).,與淋巴瘤鑒別,MR imaging and CT findings in 65-year-old woman

21、with lymphoma. A, Axial T2-weighted and,B, contrast-enhanced axial T1-weighted MR images demonstrate bilateral lesions with diffuse enhancement in the white matter of both parieto-occipital lobes. Signal intensities of

22、the enhancing lesions are hyperintense on the T2-weighted image. C, Unenhanced axial CT image demonstrates isoattenuation (grade 2) of the lesion in the left parietal lobe (arrowhead).,淋巴瘤,T1WI C+,腫瘤位于側(cè)腦室旁，形狀和輪廓均不規(guī)則，明顯增強

23、。,（例２）,膿腫,女性，47歲，出現(xiàn)持續(xù)數(shù)個月的虛弱,,The mass has well defined borders and partially effaces the atrium (trigone) of the left lateral ventricle. There is mild patchy enhancement. DWI images demonstrate increased signal throughou

24、t, but only the even more hyperintense rim demonstrates true restricted diffusion on ADC images. The remainder of the mass is increased signal on ADC images, indicating increased diffusivitiy.,膿腫,多發(fā)性硬化,多發(fā)病灶與MS難鑒別，占位效應明顯

25、腫瘤樣脫髓鞘病變長期隨訪復發(fā)少見（Kepes等隨訪31例9-12年，28例未復發(fā)）,F 28Y，病灶呈類圓形，病灶位于兩側(cè)腦室旁、右側(cè)顳葉及胼胝體。,MS 多發(fā)病灶,“黑洞”、“核心”+“暈環(huán)”現(xiàn)象,,轉(zhuǎn)移瘤皮髓交界處多見，水腫廣泛，而腫瘤樣脫髓鞘病變分布在深部腦白質(zhì)年齡,,,1，病灶多發(fā)2，兩側(cè)腦室旁及額頂葉深部白質(zhì)3，病灶較大，部分病灶呈融合狀4，信號：與急性MS病灶相似5，強化：結(jié)節(jié)狀急性或亞急性起病，多見于兒童

26、及青少年。 病前多有病毒感染或疫苗接種史，病變以靜脈性脫髓鞘主 ．累及范圍廣泛．常同時累及腦和脊髓．病程急,急性播散性腦脊髓炎,播散性腦脊髓炎,Balo's concentric sclerosis （BCS）同心圓硬化,一種少見的脫髓鞘病變，被認為是多發(fā)性硬化的一種變異病理學上表現(xiàn)為環(huán)狀正常髓磷脂或髓鞘再生與脫髓鞘病變相交替，累及大腦半球、腦干、脊髓和視交叉。病變位于腦室周，類似于其他的多發(fā)性硬化，常多發(fā)以頂葉半卵圓中