病理与临床特点
大脑胶质瘤病( gliomatosis cerebri,GC)2007 年被列入星形细胞起源肿瘤,特点是肿瘤细胞极度弥漫性浸润,正常结构相对保存,不形成肉眼可见的肿块,WHO 为Ⅱ-IV 级,多数为Ⅲ级。曾称为弥漫性胶质瘤(diffuse glioma)、弥漫性中枢神经鞘病(diffuse central schwannosis)及弥漫性大脑胶质瘤病(diffuse cerebral lipomatoSis)1938年 Nevin 首次提出GC 的命名。GC 作为一独立疾病已从 2016年 WHO 新分类中删去,认为是多种胶质瘤的生长方式,见于 IDH 突变的星形细胞瘤和少突胶质细胞瘤以及 IDH 野生型的胶质母细胞瘤,即现在认为是多种弥漫型胶质瘤亚型的特殊类型。肿瘤呈浸润性生长,脑结构仍保留,大体病理难以辨认肿瘤边界。镜下肿瘤由中等密集程度圆形或拉长的瘤细胞组成,分化程度不同,染色质丰富,偶见间变。灰白质内均见瘤细胞,但解剖结构仍存在,肿瘤细胞沿神经元周围、血管周围及柔脑膜下浸润。部分病例 GFAP及 S-100 染色阳性。发病高峰年龄为 20~50岁,无明显性别差。临床表现无特异性,包括智力下降及人格改变。本病预后不良,中位生存期14个月。化疗可能为本病有效的首选治疗方法。
Brain glioma disease (gliomatosis cerebri, GC) in 2007 was listed in astrocytes on the origin of tumor, is characterized by diffuse infiltration of the tumor cells are, normal structure relative to save, do not form visible lump, WHO is Ⅱ - level IV, mostly Ⅲ level. GC was first named by Nevin in 1938 after diffuse glioma and diffuse central schwannosis and diffuse lipomatoSis of the brain. GC, as an independent disease, has been deleted from the new classification of WHO in 2016 and is considered to be the growth mode of a variety of gliomas, which can be seen in astrocytomas and oligodendrogliomas with IDH mutations and glioblastomas with IDH wild-type glioblastomas, which are now considered to be special types of a variety of diffuse glioma subtypes. The tumor showed invasive growth, and the brain structure remained. Microscopically, the tumor consists of moderately dense rounded or elongated tumor cells with varying degrees of differentiation, rich chromatin, and occasional interchanges. Tumor cells were found in the gray matter, but the anatomical structure was still present. Tumor cells infiltrated along the periphery of neurons, blood vessels and submeninges. GFAP and s-100 were positive in some cases. The peak age of the disease was 20~50 years old, and there was no significant gender difference. Clinical manifestations are not specific, including intellectual decline and personality changes. The prognosis is poor and the median survival is 14 months. Chemotherapy may be the first effective treatment for this disease.
CT与 MRI 特点
①部位与形态:可侵犯脑各部位,但 3/4 位于大脑半球,丘脑与基底核常受累,半数病例同时侵犯中脑,脑桥、小脑及延髓也可受侵。肿瘤范围广,累及3 个脑叶以上,边界不清。病变处脑回增粗及脑沟裂变浅;
(1)location and morphology: can invade all parts of the brain, but 3/4 is located in the cerebral hemisphere, thalamus and basal ganglia are often involved, half of the cases also invade the midbrain, pons, cerebellum and medulla oblongata can also be invaded. The tumor was extensive and involved more than 3 lobes of the brain. Thickening of gyri and shallow fissions in sulcus;
②CT 检查为等或低密度,常难以分辨,间接征象为局部脑肿胀、灰白质界面消失,可形似血管病或代谢中毒性疾病。增强扫描多无强化,少数病例晚期可见模糊的斑片状或环状强化;
(2)CT examination is equal or low density, often difficult to distinguish, indirect signs for local brain swelling, gray matter interface disappeared, can be shaped like vascular disease or metabolic toxic diseases. There was no enhancement in most of the enhanced scans, and there were some fuzzy patchy or annular enhancement in the late stage in a few cases.
③T1WI 表现为境界不凊的等或稍低信号,脑回增粗,灰白质界面欠清。T2WI及FLAIR 为弥漫性高信号,界限不清,有时内部见少许更高信号。DWI 一般无扩散受限,少数为轻中度高信号,DTI显示纤维束无破坏。MRS近似正常,或见Cho与mI增高及NAA下降。增强扫描约半数病例出现局限性或弥漫性轻中度强化,呈斑片状,强化区代表该处肿瘤级别较高。原发于脑膜GC可见脑膜异常增厚及强化,形似脑膜癌病。
(3)T1WI of state not part or slightly low signal, such as enlargement of gyri, gray matter interface. T2WI and FLAIR are diffuse hyperintensity, with blurred boundaries and sometimes a few higher signals inside. DWI generally has no diffusion limitation, and a few are light to medium high signals. DTI shows no damage to fiber bundles. MRS was approximately normal, or Cho and mI increased and NAA decreased. About half of the cases presented localized or diffuse mild to moderate enhancement in the enhanced scan, which was patchy, and the enhanced area represented higher tumor grade. Abnormal thickening and enhancement of the meninges, similar to meningeal carcinomatosis, were observed by GC。
鉴别诊断
需与多种弥漫性病变鉴别。
①多发性硬化,病灶一般多发,但较局限,增强扫描可见开环状强化,临床特点为症状反复发作与进行性加重;
(1)multiple sclerosis, lesions generally multiple, but more limited, enhanced scan can be seen open ring enhancement, clinical characteristics of recurrent symptoms and progressive aggravation;
②脑炎与本病鉴别困难,但脑炎可有前驱病毒感染,临床上有发热及脑脊液异常等;
(2)encephalitis and the disease is difficult to identify, but encephalitis can have progenitor virus infection, clinical fever and cerebrospinal fluid abnormalities;
③线粒体脑肌病,反复中风样发作,但病变常为非血管性分布,MRA 显示血管正常或轻度异常,MRS显示Lac 增高。肌肉活检可确诊;
(3)mitochondrial encephalomyopathy, repeated stroke-like attacks, but the lesions were usually nonvascular distribution,MRA showed normal or mild abnormalities of blood vessels, and MRS showed increased Lac. Muscle biopsy can be confirmed;
④脑缺血及动脉硬化性脑病,前者常为某一动脉分布区异常,急性发病,DWI及 MRA 可见明显异常;后者以幕上脑皮质下白质及脑室周围为著,对称分布,不累及脑皮质;
(4)cerebral ischemia and arteriosclerotic encephalopathy, the former is often an abnormal artery distribution area, acute onset,DWI and MRA can be clearly abnormal; The latter was distributed symmetrically in the supratentorial subcortical white matter and around the ventricle, and did not involve the cerebral cortex.
⑤肾上腺脑白质营养不良为遗传性疾病,典型影像学表现为累及三角区周围白质的蝴蝶状异常密度及信号,增强扫描可见病变中带强化;
(5)adrenal and cerebral leukodystrophy is a genetic disease, and the typical imaging manifestations are abnormal butterfly density and signal of white matter around the triangle region, which can be seen in enhanced scan.
⑥亚急性硬化性全脑炎为麻疹病毒介导脑炎,病变对称累及顶叶与枕叶,T1WI 低信号,T2WI 弥漫性高信号,增强扫描无强化。
(6)Subacute sclerosing panencephalitis is measles virus mediated encephalitis, lesions symmetric involving the parietal lobe and occipital lobe,T1WI low signal,T2WI diffuse high signal, enhanced scanning without enhancement.
简要讨论
GC 的特点是至少累及3个脑叶,通常侵犯基底核与大脑深部白质,影像学表现明显,而临床症状相对较轻,病变进展缓慢,肿瘤内可并存多种级别的肿瘤性星形细胞,因此活检有可能低估肿瘤级别,应在功能MRI(如MRS)指导下进行取材。
GC is characterized by involvement at least three lobes, usually infringement of basal ganglia and deep brain white matter, imaging findings, and clinical symptoms are relatively mild, pathological changes slowly, tumor can coexist in a variety of levels of tumor astrocytes, therefore biopsy may underestimate the level of tumor, should be under the guidance of functional MRI (MRS) of materials.
