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Adult Tumors of the Posterior Fossa
Hemangioblastoma 血管母细胞瘤，血管网状细胞瘤（血网） Dysplastic Cerebellar Gangliocytoma 发育不良性神经节细胞瘤 Subependymoma 室管膜下瘤
confirmation
MRI是诊断的最佳方式 特征性表现 几乎可在不需要病理证实
的条件下做出明确诊断
typical appearances 1. unilateral cerebellar mass 2. non-enhancing 3. middle-aged patient 4. tiger-striped pattern
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Dysplastic Cerebellar Gangliocytoma
Pathologic Findings
免疫组化染色显示神经元 特异性蛋白酶及突触素阳 性表达
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Dysplastic Cerebellar Gangliocytoma
Imaging Findings-CT
NCCT usually hypoattenuated may be isoattenuated Calcification is
Incidence and Clinical Presentation Originally described in 1920 also called LhermitteDuclos disease (LDD) neoplastic histogenesis Vs. hamartomatous origin young adults: average age 34 years no gender predilection 1920年首次报道 又称为LDD 早期研究认为其为肿瘤 性病变，现认为其为错 构瘤样改变 常见于年轻人，中位发 病年龄34岁 无性别差异
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Subependymoma
Incidence and Clinical Presentation
1945年由Scheinker首次报道
占颅内全部肿瘤的不足1% 大多数学者认为室管膜下瘤是室管膜瘤的一种类型
室管膜下瘤、中枢神经细胞瘤、室管膜下巨细胞星 形细胞瘤Subependymoma, central neurocytoma, subependymal giant cell astrocytoma具有相同的起 源，均起源于室管膜下的具有双向分化潜能的神经 胶质祖细胞Glial progenitor cells
常见临床症状 颅内压增高 脑积水 巨脑畸形 精神障碍 症状时间 不定
duration of symptoms considerable variability asymptomatic
甚至也可无症状
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Dysplastic Cerebellar Gangliocytoma VS Cowden disease
正常小脑板层结构破坏
大量增生肥大的神经节 细胞 侵蚀小脑皮层的颗粒层 和分子层
分子层髓鞘化增加
病理组织切片上有丝分 裂活性及坏死少见
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Dysplastic Cerebellar Gangliocytoma
Pathologic Findings
×100 ×200 hypertrophic ganglion cells expanding the granular and molecular layers of the cerebellar cortex
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Dysplastic Cerebellar Gangliocytoma
Imaging Findings-MRI
各向异性分数（fractional anisotropic, FA）方向彩色编码 图上正常小脑区域呈绿色(表示前后走行)，肿瘤区以红色 为主(表示左右走行)，未见条样信号。图5 纤维束追踪成 像像(Fiber tractography）。fiber tract within the tumor肿 瘤区纤维束以左右方向走行为主。 16/64
Imaging Findings-MRI
1.5T SWI MIP图像显示瘤周引流静脉，7T SWI MIP图像显示瘤 周大量引流静脉及齿状核受压
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Dysplastic Cerebellar Gangliocytoma
Imaging Findings-MRI
图1 MRI平扫轴位T1WI(A)，增强扫描轴位T1WI(B)，左侧小脑半球可见一团 块状长T1、长T2异常信号影，边界清楚，其内信号不均匀，可见条纹状等T1、 T2信号影。增强扫描未见明显强化。图2 各向异性分数（fractional anisotropic, FA）灰度图，肿瘤区域呈低信号。图3 ADC图，肿瘤区域呈等及稍 高信号
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Dysplastic Cerebellar Gangliocytoma
Incidence and Clinical Presentation
commonly symptoms increased intracranial
pressure hydrocephalus Megalencephaly mental retardation
Clinical Presentation
Cowden disease autosomal dominant hamartoma syndrome characterized syndrome mucocutaneous lesions macrocephaly hamartomas long arm of chromosome 10
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Subependymoma
Incidence and Clinical Presentation
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Subependymoma
Incidence and Clinical Presentation rare, benign, slowgrowing tumor generally well-circumscribed sometimes multiple lesions most frequently: fourth ventricle distinctive histologic appearance histogenesis: controversial 良性肿瘤，生长缓慢 通常边界清楚 可为多发 常见于四脑室 病理学表现典型 组织学发生有争议
Adult Tumors of the Posterior Fossa
Hemangioblastoma 血管母细胞瘤，血管网状细胞瘤（血网） Dysplastic Cerebellar Gangliocytoma 发育不良性神经节细胞瘤 Subependymoma 室管膜下瘤
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Dysplastic Cerebellar Gangliocytoma
uncommon Thinning of the skull
CT平扫 常为低密度 但也可为等密度 无特异性 诊断困难 钙化少见 偶可见颅板变薄
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Dysplastic Cerebellar Gangliocytoma
Imaging Findings-MRI MRI：best imaging modality characteristic appearance without histopathological
四条特征 1. 单侧半球肿块 2. 不强化 3. 成年患者 4. 虎斑征
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Dysplastic Cerebellar Gangliocytoma
Imaging Findings-MRI
characteristic: bands hyperintensity and
isointensity on T2 isointense and hypointense on T1 hyperintense signal on T2 corresponds to the inner molecular layer, granular cell layer, and loss of central white matter
PART TWO
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SUMMARY
Often Occurs in middle-aged men 好发于中年男性 fourth ventricle and lateral ventricle 多位于四脑室和侧脑室 Mass, clearly edge 团块状、边缘较清楚 no or slight Enhanced 增强扫描后，多无强化或轻微强化
Cowden病 常染色体显性遗传 错构瘤样病变 特征性表现 皮肤粘膜病变 巨脑畸形 错构瘤
10号染色体长臂异常
4Байду номын сангаас64
Dysplastic Cerebellar Gangliocytoma
Pathologic Findings
disruption of the normal cerebellar laminar structure hypertrophic ganglion cells granular and molecular layers of the cerebellar cortex increased myelination in the molecular layer Mitotic activity and necrosis are uncommon
Dysplastic Cerebellar Gangliocytoma
Imaging Findings-MRI
虎斑征，条纹征
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Dysplastic Cerebellar Gangliocytoma