第241课 （中枢神经）病例探析（064）-多形性胶质母细胞瘤

女性，74岁。头痛数月

最后诊断：形性胶质母细胞瘤。

病理与临床特点

多形性胶质母细胞瘤( glioblastoma multiforme,GBM)是最常见的颅内原发肿瘤,约占颅内肿瘤 15%—20%及星形细胞起源肿瘤的 2/3~3/4,是成人幕上最常见原发脑肿瘤。WHO 分级为Ⅳ级, WHO分类中属于弥漫性星形细胞与少突胶质细胞肿瘤,包括异柠檬酸脱氢酶(IDH)基因野生型、突变型及 NOS型。本病从病程上分为原发性与继发性两种类型,原发者可在数月内突然出现(既往影像学资料证明无病变),继发者为较低级别肿瘤基础上缓慢进展所致。肿瘤分化不良,常见坏死、出血及血管增生明显，瘤细胞多形性及间变显著,血管周围可见淋巴细胞浸润。免疫组织化学染色 GFAP、Olig2、IDH-1(+),K67明显增高。发病高峰为 45~70岁,无明显性别差异或男性较多。临床表现包括抽搐、局部神经功能障碍及中风样症状、头痛。预后不良,中位生存期不足1 年。

Glioblastoma multiforme (GBM) is the most common primary intracranial tumor, accounting for about 15%-20% of intracranial tumors and 2/3~3/4 of astrocytic tumors, and is the most common primary brain tumor in adults. The WHO classification for Ⅳ level, in the WHO classification belongs to diffuse astrocytes and oligodendrocytes in tumor, including isocitrate dehydrogenase (IDH) genotype of wild type and mutant and NOS. The disease can be divided into two types: primary and secondary. The primary disease can occur suddenly within a few months (no lesion has been proved by previous imaging data), and the secondary disease is caused by slow progression of lower-grade tumors. The tumor was poorly differentiated, with obvious necrosis, hemorrhage and vascular hyperplasia, prominent pleomorphism and interstitial changes of tumor cells, and lymphocyte infiltration around the blood vessels. Immunohistochemical staining showed significant increase of K67 in GFAP, Olig2 and idh-1 (+). The peak of the disease was 45~70 years old, with no significant gender difference or more males. Clinical manifestations include convulsions, local neurological dysfunction, stroke-like symptoms, and headache. Poor prognosis, median survival less than 1 year.

CT与 MRI 特点

①部位及形态:好发于幕上大脑半球深部白质,依次为额叶、顶叶与颞叶,其次为基底核与丘脑,幕下脑质少见,主要见于儿童脑干。幕上病变可经胼胝体侵入对侧大脑半球,形成“蝶翼状”外观。病变大小 不一,但一般较大,显著不均质,瘤周水肿明显,囊变/坏死率高达 95%,占位征明显。肿瘤沿白质纤维束蔓延,约 1/5 病例就诊时呈“多灶性”。少数呈弥漫浸润状,无明确肿块;

(1) location and morphology: good hair in the supratentorial brain hemisphere deep white matter, followed by the frontal lobe, parietal lobe and temporal lobe, followed by basal nucleus and thalamus, subtentorial brain quality is rare, mainly in children"s brain stem. Supratentorial lesions can invade the contralateral cerebral hemisphere through the corpus callosum, forming the appearance of "butterfly wing". The size of the lesion varies, but it is generally large with significant heterogeneity. The peritumor edema is obvious, and the rate of cystic degeneration/necrosis is as high as 95%, and the occupying sign is obvious. The tumor spread along the white matter fiber bundles, and about one fifth of the cases presented "multifocal" at the time of admission. Few were diffuse infiltrating without definite mass.

②CT 上呈密度显著不均,中心为低密度,钙化少见,约 1/5 可见出血。瘤周水肿显著,呈沿白质束延伸的低密度。实性部分强化显著及不规则,多为厚薄不均的环状强化,厚薄不均,可见结节状改变。少数轻微强化或无强化。血管丰富者可见粗大血管进入肿块;

(2) on CT, the density was significantly uneven, the center was low density, calcification was rare, and about 1/5 of the bleeding was visible. Peritumor edema was significant, with a low density extending along white matter tracts. The solid part of the enhancement was marked and irregular, most of which were annular enhancement with uneven thickness. Nodular changes were observed. A few slight or no enhancement. Large vessels can be seen in those with abundant blood vessels entering the mass.

③MRIT1W 上为境界不清的混杂信号肿块,囊变区为更低信号。T2WI为不均匀高信号,瘤周有时见血管流空信号。瘤周水肿呈 T1WI低信号及 T2WI高信号。T2WI与 SWI 能更好地检出瘤内出血及血管增多。肿瘤显著强化,呈不规则花环状、结节状、点状、斑片状。DWI显示扩散受限,MRS可见 Cho及 Cho/Cr 明显升高、NAA与m 下降、Iac 增高。PWI 显示 CBV 及血管通透性均增大.

(3) MRIT1W is a mixed signal mass with unclear boundary, and the cystic degeneration area is lower signal. T2WI showed uneven and high signal, and sometimes empty signal of blood vessel flow was observed around the tumor. Peritumor edema showed low signal on T1WI and high signal on T2WI. T2WI and SWI can better detect intratumoral bleeding and increased blood vessels. The tumor was significantly enhanced, showing irregular annular, nodular, punctate and patchy patterns. DWI showed that diffusion was limited, Cho and Cho/Cr in MRS were significantly increased, NAA and m were decreased, and Iac was increased. PWI showed increased CBV and vascular permeability.

鉴别诊断

①脑脓肿,有感染症状,环内壁较光整,DWI示囊液扩散受限,MRS 显示水肿区无肿瘤波谱;

(1) brain abscess, with infection symptoms, smooth inner wall of the ring, limited diffusion of cystic fluid by DWI, and no tumor spectrum in the edema area shown by MRS;

②脑转移瘤,有原发瘤病史,好发于灰白质交界区,水肿及强化显著;

(2) brain metastases, with a history of primary tumor, tend to occur in the junction of gray and white matter, edema and enhancement are significant;

③吸收期血肿,MRI 显示血肿降解不同时期信号特点,T2W与SWI显示血肿周边含铁血黄素所致的低信号;

(3) absorption phase hematoma,MRI showed signal characteristics of degradation of hematoma at different stages,T2W and SWI showed low signal caused by hemosiderin around hematoma;

④脑梗死,偶在某一断面上呈环状强化而形似肿瘤,DWI示扩散受限,PWI 为低灌注;

(4) cerebral infarction, which sometimes presented annular enhancement in a certain section and looked like tumor, limited diffusion in DWI and low perfusion in PWI;

⑤脱髓鞘病,需结合病史、诱发电位及 MRS 等资料鉴别。

(5) demyelination disease, need to combine history, evoked potential and MRS and other data to identify.

简要讨论

本病特点为肿瘤显著不均质性及花环状强化。由于 GBM 呈浸润性生长,CT与 MRI 均不能显示肿瘤的真正“边界”。CTP与PWI能提供病变微血管水平信息,可更好地指明肿瘤边界,并有效区分肿瘤放射性坏死与术后复发。

This disease is characterized by marked heterogeneity of the tumor and annular enhancement of the flower. Due to the invasive growth of GBM, neither CT nor MRI can show the true "boundary" of tumor. CTP and PWI can provide information on the level of lesion microvessels, better indicate tumor boundaries, and effectively distinguish tumor radiation necrosis from postoperative recurrence.