弥漫性中线胶质瘤( diffuse midline gliomas 是2016年 WHO CNS肿瘤分类新增的一种病理类型,是一组原发于儿童,偶见成年人,位于中线结构(丘脑、脑干及脊髓),呈弥漫浸润性生长的胶质瘤,伴有组蛋白H3K27M的突变。这类肿瘤包括以往的弥漫内生型脑桥胶质瘤( diffuse intrinsic pontine gliomas,DPGs)。此类肿瘤恶性度高,预后差,2年生存率<>
Diffuse midline gliomas (diffuse midline gliomas) is a new pathological type of WHO CNS tumor classification added in 2016. It is a group of gliomas primarily occurring in children and occasionally in adults, and occupying the midline structure (thalamus, brainstem and spinal cord) with diffuse infiltrating growth accompanied by mutations of histone H3K27M. These tumors include diffuse endogenous pontine gliomas (DPGs). Such tumor malignant degree is high, the prognosis is poor, 2 year survival rate < 10%,="" the="" who="" classification="" for="" ⅳ="" level.="" in="" addition="" to="" the="" pons,="" thalamus="" and="" spinal="" cord,="" the="" tumor="" can="" also="" be="" seen="" in="" the="" ventricle,="" corpus="" callosum,="" hypothalamus,="" pineal="" gland="" and="" cerebellum,="" with="" the="" pons="" and="" thalamus="" being="" the="" most="" common.="" the="" average="" age="" of="" most="" tumors="" was="" 7="" to="" 11="" years="" old,="" and="" the="" onset="" age="" of="" tumors="" in="" the="" pons="" was="" slightly="" earlier,="" about="" 7="" years="">
弥漫性中线胶质瘤的临床表现多变,发病部位不同,其临床表现亦不同。发生在脑桥者可出现典型“三联征”:脑神经损害(复视和面部不对称)共济失调和长束体征,其症状出现的相对较急,常小于1个月。尽管部分患者症状轻微,但可在数月内进展。随着病情进展,肿瘤可压迫第四脑室,引起梗阻性脑积水。组织病理学上,绝大多数弥漫性中线胶质瘤为纤维型星形细胞瘤,具有高级别星形细胞瘤的坏死、血管增生及有丝分裂象增多的特征,低级别星形细胞瘤和毛细胞型星形细胞瘤比较少见。发生在丘脑的弥漫性中线胶质瘤主要表现为颅内压增高、中枢性尿崩、运动功能障碍、感觉功能障碍、视物功能障碍、不自主运动、癫痫和行为障碍等症状。由于脑干内布满重要神经核团和纤维,周围血管众多,且肿瘤呈浸润性生长,所以手术不能给患者带来好处,往往可能加重神经损伤。目前国际认可的标准治疗方案是传统的放射治疗,但治疗效果也仅限于暂时缓解症状。
The clinical manifestations of diffuse midline glioma vary from place to place. The typical 'triad' of cerebral nerve damage (diplopia and facial asymmetry) ataxia and long bundle signs occurs in the pons, where symptoms are relatively acute, often less than 1 month. Although some patients have mild symptoms, they can progress within months. As disease progress, tumor can compress the 4th ventricle, cause obstruction hydrocephalus. Histopathologically, the majority of diffuse midline gliomas are fibroid astrocytomas, characterized by necrosis, angiogenesis and increased mitosis in high-grade astrocytomas, while low-grade astrocytomas and hair cell astrocytomas are relatively rare. Diffuse midline glioma in thalamus mainly presents as increased intracranial pressure, central diabetes insipidus, motor dysfunction, sensory dysfunction, visual dysfunction, involuntary movement, epilepsy and behavioral disorder. Because the brain stem is filled with important nerve nuclei and fibers, surrounding blood vessels are numerous, and the tumor shows invasive growth, surgery can not bring benefits to patients, often aggravating nerve damage. Currently, the internationally accepted standard treatment is traditional radiotherapy, but the therapeutic effect is limited to temporary relief of symptoms.
大体所见受累脑组织肿胀、坚硬,灰白质交界模糊，但尚完整。显微镜下显示典型的组织学特点为小胶质细胞增生,其细胞核拉长呈梭形;可见胶质细胞,尤其是星形细胞形态呈多形性,包括内含多形细胞核的较大肿瘤细胞。
In general, the affected brain tissue is swollen and hard, with a blurred border of gray and white matter, but it is still intact. Microscopically, the typical histological features are microglial hyperplasia with elongated spindle nuclei. Note that glial cells, especially astrocytes, are pleomorphic, including larger tumor cells with polymorphic nuclei.
影像学检查受累脑组织肿胀增大,脑组织结构通常无破坏。CT平扫显示病灶呈稍低或等密度,境界不清,增强扫描无强化。中线结构常无移位,或移位不明显。MRI的质子密度加权、T2加权像和FLAIR像均显示病灶为弥漫性高信号,T1加权像为等或稍低信号,境界不清。MRI增强扫描病灶无强化,或少许强化。MRI在显示肿瘤病灶范围和累及胼胝体等方面的效果优于CT。
Imaging examination of the affected brain tissue swelling increased, the brain tissue structure is usually not damaged. CT plain scan showed slightly lower or equal density of the lesion, unclear boundary, and no enhancement on enhanced scan. Midline structures are often unshifted or not clearly displaced. In MRI, proton density weighted, t2-weighted and FLAIR images all showed diffuse hyperintensity, and t1-weighted images showed equal or slightly low signal with blurred boundary. MRI enhanced scan showed no enhancement or little enhancement. MRI is better than CT in showing tumor focus and corpus callosum.
鉴别诊断
1.渗透性脱髓鞘综合征是一种特殊的脱髓鞘疾病,病变可累及中枢神经系统多个部位。根据发病部位不同,分为脑桥中央髓鞘溶解症(central potine myelinolysis,cPM)和脑桥外髓鞘溶解症(extrapontine myelinolysis,EPM)CPM表现为对称性累及脑桥中央,EPM累及脑桥以外的区域,如基底节、丘脑、小脑、皮质下白质等部位,二者可单独发生也可合并发生。渗透性脱髓鞘综合征的病因多为快速纠正低钠血症后,尤其是伴有慢性酒精中毒、器官移植、长期营养不良、恶性肿瘤、糖尿病酮症酸中毒等慢性消耗性疾病的患者。在CT上表现为脑桥中央或脑桥外病灶处的低密度影,MR表现为对称性长T1、长T2信号影,病灶呈“蝙蝠翅”样, FLAIR显示更清楚,增强扫描多无强化,少数可见明显强化。渗透性脱髓鞘综合征在影像学检查上存在“延迟效应”MR往往在临床表现出现1-2周后才显示病变。结合临床病史及特殊的影像学表现,可对本病进行诊断。
Osmotic demyelination syndrome is a special demyelination disease, which can involve many parts of the central nervous system. Depending on the location of disease,cPM can be divided into central potine myelinolysis (cPM) and extrapontine myelinolysis (EPM). The involvement of cPM in the central pons is symmetrical, and that of EPM in areas beyond the pons, such as basal ganglia, thalamus, cerebellum, and subcortical white matter, can occur independently or in combination. The cause of osmotic demyelination syndrome is usually the rapid correction of hyponatremia, especially in patients with chronic wasting diseases such as chronic alcoholism, organ transplantation, long-term malnutrition, malignant tumor and diabetic ketoacidosis. On CT, low-density shadows at the center of the pons or the lesions outside the pons were presented. MR presented symmetrical long T1 and long T2 signal shadows. The lesions were 'pteripid' like, FLAIR showed more clarity, most of the enhanced scans had no enhancement, and few showed obvious enhancement. The osmotic demyelination syndrome has a 'delayed effect' on imaging examination. MR usually shows the lesion 1-2 weeks after the clinical manifestation. Combined with clinical history and special imaging findings, this disease can be diagnosed.
2.急性播散性脑脊髓炎为一种较常见的脑脊髓弥漫性炎症脱髓鞘疾病,常发生于感染或疫苗接种后。可发生于任何年龄,但多见于儿童及青年。病变可同时累及基底节、丘脑、脑干及小脑,病灶常多发,急性期CT呈低密度,MR呈长T1、长T2信号,DWI表现为高信号,增强扫描呈显著强化,慢性期表现为脑萎缩。根据病灶数目、形态、信号特点及临床病史可进行诊断。
Acute disseminated encephalomyelitis is a common demyelination disease with diffuse inflammation of the cerebral and spinal cord. It usually occurs after infection or vaccination. It can occur at any age but is more common in children and young adults. Lesions can involve basal ganglia, thalamus, brainstem and cerebellum at the same time, and lesions are often multiple. In the acute phase, CT shows low density,MR shows long T1 and long T2 signals,DWI shows high signal, enhanced scan shows significant enhancement, and slow phase shows brain atrophy. Diagnosis can be made according to the number, morphology, signal characteristics and clinical history of lesions.
