儿童后颅窝脑肿瘤

1/64,Pediatric Neoplasms of the Posterior Fossa儿童后颅窝脑肿瘤,2/64,Pediatric Neoplasms of the Posterior Fossa,颅内高压征多呈渐进性患儿常无典型颅高压三联征表现，视乳头水肿少见多以头痛和/或呕吐为主要就诊原因呕吐易与多种消化道疾病相混淆侵犯小脑半球和小脑蚓部可导致躯体和四肢共济失调但学龄儿活动范围较大，症状常发现较晚,临床症状不典型,3/64,Pediatric Neoplasms of the Posterior Fossa,婴儿囟门未闭，学龄儿及幼儿颅缝闭合不紧临床以头围异常增大为主要体征，易被家长忽视小儿神经系统发育不完善，小脑损害征不易察觉临床表现无特异性，易与神经系统感染相混淆,早期体征不明显,4/64,5/64,6/64,Pediatric Neoplasms of the Posterior Fossa -Series topic,Medulloblastoma 髓母细胞瘤Pilocytic AstrocytomaEpendymomaChoroid Plexus Papilloma and Carcinoma,7/64,以神经胶质瘤和神经元两种未分化的神经上皮细胞为基础形成的肿瘤镜下细胞形态很像胚胎期的髓母细胞1926年由Bailey和Cushing命名为髓母细胞瘤新的WHO分类将其归为幕下原始神经外胚层瘤（PNET）,Incidence and Clinical Presentation,Medulloblastoma髓母细胞瘤,8/64,most common pediatric central nervous system malignancy 最常见的儿童原发脑肿瘤（15%25%）second most common pediatric brain neoplasm最常见的儿童后颅窝原发脑肿瘤（33%）Males (60%) are slightly more commonly男性常见the mean age is about 7 years平均好发年龄7岁，也可见于20到40岁（但成人少见）,Incidence and Clinical Presentation,Medulloblastoma髓母细胞瘤,9/64,most arise in the midline cerebellar vermis多见于小脑蚓部，以中下蚓多见lateral location within the cerebellar hemisphere：older children年长儿及青少年（大龄组）多见于小脑半球other location: Brain stem, the fourth ventricle, spinal cord其它部位：脑干、四脑室、脊髓,Incidence and Clinical Presentation,Medulloblastoma髓母细胞瘤,10/64,clinical presentation：usually less than 3 months肿瘤的侵袭性生物学特性：病程通常短于三个月common symptoms: Headache and persistent vomiting常见症状：头痛或持续性呕吐Truncal ataxia and spasticity共济失调和痉挛状态Abducens nerve palsy外展神经麻痹,Incidence and Clinical Presentation,Medulloblastoma髓母细胞瘤,11/64,Pathologic Findings,Medulloblastoma髓母细胞瘤,手术标本灰红色或粉红色，边缘清楚，无明确包膜，柔软易碎,尸检标本位于小脑上蚓部肿块，边界清楚,12/64,gross appearance: variable大体病理表现多样most common subtype: classic subtype最常见的亚型为经典型Other subtypes: desmoplastic subtype, “medulloblastoma with extensive nodularity and advanced neuronal differentiation” subtype, and the large cell medulloblastoma subtype其它亚型包括：纤维组织型、高分化型和大细胞型镜下特点为细胞排列非常致密，呈菊花团状，主要为小圆细胞组成，胞浆少，核大且浓染,Pathologic Findings,Medulloblastoma髓母细胞瘤,13/64,免疫组织化学表现及应用 尿激酶型纤酶原激活剂(urokinase type plasminogen activator, uPA)与肿瘤浸润转移关系密切血管内皮生长因子受体(vascular endothelial growth factor receptor-2, KDR)与肿瘤血管生成及其转移密切相关uPA或KDR高表达的患者，其平均生存时间均较低表达者短可作为预测髓母细胞瘤预后的指标,Pathologic Findings,Medulloblastoma髓母细胞瘤,14/64,hyperattenuated well-defined边缘清楚的高密度（特征性）surrounding vasogenic edema血管源性水肿fairly uniform contrast enhancement均匀强化,Imaging Findings,Medulloblastoma髓母细胞瘤,15/64,Imaging Findings MRI诊断要素,Medulloblastoma髓母细胞瘤,儿童者多位于小脑中下蚓部，突向四脑室，轴位可见第四脑室受压变扁，呈弧形包绕在肿瘤前方和侧面，幕上脑室阻塞性脑积水发生于小脑，多呈类圆形，瘤周水肿较轻，邻近脑实质受挤压坏死、囊变、出血及钙化少见肿瘤实性部分在所有MRI序列上均与脑灰质信号相近由于MB生长迅速，质地软，信号相对较均匀增强扫描肿瘤实性部分明显强化容易发生沿脑脊液通路在蛛网膜下腔种植转移,16/64,Imaging Findings MRI新技术,Medulloblastoma髓母细胞瘤,DWI弥散受限MRS：Choline，NAACr，Lac（occasionally）特征性的氨基乙磺酸峰MRA可显示起于小脑后下动脉的供血血管,17/64,Imaging Findings,Medulloblastoma髓母细胞瘤,T1WI,T2WI,FLAIR,Gd-DTPA,DWI,ADC,男性,8岁,小脑蚓部髓母细胞瘤,肿瘤呈类圆形,边界清晰图1T1WI呈略低信号,肿瘤前方可见弧形四脑室脑脊液信号图2同一层面T2WI呈略高信号图3FLAIR呈略高信号图4增强T1WI肿瘤呈明显对比增强图5DWI瘤体呈略高于脑实质信号,囊变区呈低信号,18/64,9-year-old boy with medulloblastoma. On diffusion-weighted image, lesion shows restricted diffusion,弥散受限的机制,肿瘤细胞密度高细胞外间隙小肿瘤细胞的胞浆少核浆比例较大,Imaging Findings,Medulloblastoma髓母细胞瘤,19/64,Medulloblastoma髓母细胞瘤,20/64,Medulloblastoma髓母细胞瘤,21/64,Subarachnoid seeding is common in medulloblastomas髓母细胞瘤常见蛛网膜下腔播散，经由脑脊液在脑室和蛛网膜下腔内种植转移，增强扫描，转移灶同原发灶一样发生显著对比增强种植灶呈均匀结节状或不规则环状中度至明显强化Post-operative hemorrhage：hampered subarachnoid seeding手术后出血灶常掩盖蛛网膜下腔播散clinical and cytopathologic CSF findings临床及CSF检查有助于蛛网膜下腔播散的诊断,Imaging Findings,Medulloblastoma髓母细胞瘤,22/64,23/64,Imaging Findings,Medulloblastoma髓母细胞瘤,儿童髓母细胞瘤：小脑蚓部成人髓母细胞瘤：小脑半球差异的机制髓母细胞瘤起源于四脑室顶后髓帆神经上皮细胞的残余这种原始细胞随生长发育向上并向外移行形成小脑的外颗粒层MB可发生于此移行过程的任何部位，并限于后颅窝儿童MB多起自四脑室顶部后髓帆生殖中心的胚胎残余细胞成人MB多起源于小脑软膜下分子层表面一种较原始的小脑外颗粒层细胞,24/64,Imaging Findings,Medulloblastoma髓母细胞瘤,CT平扫（A、B）示左侧小脑半球一不规则略高密度影（），边缘不清，其周围可见带状低密度影；增强扫描（C、D）病变强化较明显（），内见不规则点、线状低密度区，四脑室受压、变窄，向右侧移位,肿瘤位于小脑半球者多见于成人,25/64,平均生存时间为9-11个月（不足1年）早期治疗手段开颅手术和传统放疗为主现今开颅手术与辅助的放疗、化疗相结合的综合治疗生长迅速，细胞分裂指数高对放疗中度敏感髓母细胞瘤术后强调早期放疗全中枢神经系统进行放疗,治 疗,Medulloblastoma髓母细胞瘤,26/64,Pediatric Neoplasms of the Posterior Fossa -Series topic,MedulloblastomaPilocytic Astrocytoma毛细胞型星形细胞瘤EpendymomaChoroid Plexus Papilloma and Carcinoma,27/64,Penfield于1937年根据肿瘤细胞两端胞突起为细长的毛发样胶质纤维丝而命名占小脑星形细胞瘤的绝大多数（85% ）好发于幕下，以小脑蚓部多见也可见于所有星形细胞所在的部位：丘脑、视交叉、小脑、脑干、大脑半球及脊髓高发年龄0-9岁无性别差异,Incidence and Clinical Presentation,Pilocytic Astrocytoma毛细胞型星形细胞瘤,28/64,common symptoms：ataxia, headache, nausea, and vomiting常见症状：共济失调、头痛、恶心呕吐prolonged clinical course：slow growth of the tumor肿瘤生长缓慢，临床病史较长excellent prognosis预后良好,Incidence and Clinical Presentation,Pilocytic Astrocytoma毛细胞型星形细胞瘤,29/64,低级别的星形细胞瘤，WHO I级良性肿瘤，生长缓慢，预后好双相性：由致密区和疏松区组成肿瘤富含丰富的血管恶性转化及复发：均少见极高的存活率，10年生存率可达94%,Pathologic Findings,Pilocytic Astrocytoma毛细胞型星形细胞瘤,30/64,Pathologic Findings,Pilocytic Astrocytoma毛细胞型星形细胞瘤,镜下特点：毛样星形细胞与疏松成熟的胶质纤维混杂排列,31/64,典型影像学特点囊性肿块伴强化的壁结节瘤周水肿少见，说明其良性肿瘤的特性无弥散受限，DWI无高信号表现,Imaging Findings,Pilocytic Astrocytoma毛细胞型星形细胞瘤,32/64,囊肿型病变呈囊性，没有壁结节或实性肿块囊肿结节型以囊性病变为主，伴有壁结节瘤囊型囊内有瘤，瘤内有囊肿块型病变以实性部分为主，伴有或不伴有囊变,Imaging Findings,Pilocytic Astrocytoma毛细胞型星形细胞瘤,33/64,脑肿瘤的强化程度与肿瘤的恶性程度呈正相关肿瘤的恶性程度越高肿瘤血管发育不成熟和血脑屏障破坏程度越重而毛细胞型星形细胞瘤的强化不代表肿瘤为恶性和血脑屏障破坏与肿瘤血管的自身特点（有孔型毛细血管）有关对比剂可通过肿瘤血管的内皮间隙到达肿瘤组织所以增强扫描时表现为实性成分的均匀明显强化而这在低级别星形细胞瘤中少见,Imaging Findings,Pilocytic Astrocytoma毛细胞型星形细胞瘤,34/64,Imaging Findings,Pilocytic Astrocytoma毛细胞型星形细胞瘤,囊肿结节型，壁结节明显强化,35/64,Imaging Findings,Pilocytic Astrocytoma毛细胞型星形细胞瘤,囊肿结节型，壁结节明显强化瘤周水肿不明显，说明其良性特点,36/64,Imaging Findings,Pilocytic Astrocytoma毛细胞型星形细胞瘤,瘤囊型：囊内有瘤，瘤内有囊,37/64,Imaging Findings,Pilocytic Astrocytoma毛细胞型星形细胞瘤,小脑蚓部毛细胞星形细胞瘤，肿瘤以实性为主，呈明显不均匀强化，其内可见多发大小不等 不强化的囊变区,肿块型,38/64,Imaging Findings,Pilocytic Astrocytoma毛细胞型星形细胞瘤,偏良性的肿瘤实质部分细胞密度小细胞间隙大水分子弥散受限较轻,良性肿瘤:弥散不受限,39/64,Pediatric Neoplasms of the Posterior Fossa -Series topic,MedulloblastomaPilocytic AstrocytomaEpendymomaChoroid Plexus Papilloma and Carcinoma,40/64,612% of all pediatric brain tumors占所有儿童脑肿瘤的612% one-third of all brain tumors in patients younger than 3 years占所有婴幼儿脑肿瘤的1/358% fourth ventricle; 42% lateral and third ventricles58%见于四脑室， 42% 见于侧脑室及三脑室mean age: 6 years old 平均发病年龄：6岁,Incidence and Clinical Presentation,Ependymoma 室管膜瘤,41/64,病程较长，呈缓慢发展过程临床表现早期因肿瘤体积小、活动性大，体位变化时可堵塞导水管或四脑室侧孔或正中孔，而引起暂时性脑脊液循环障碍，表现为发作性头痛、恶心、呕吐；当肿瘤增大充满四脑室时可造成持续性脑脊液循环障碍，引起脑积水，出现持续的头痛、恶心、呕吐。,Incidence and Clinical Presentation,Ependymoma 室管膜瘤,42/64,起源于已分化的室管膜细胞起自四脑室顶或底结节状或分叶状、膨胀性生长病理特征：血管旁假菊形团生长缓慢的胶质瘤WHO II级肿瘤出血、坏死、囊变和钙化,Pathologic Findings,Ependymoma 室管膜瘤,43/64,Pathologic Findings,Ependymoma 室管膜瘤,病理切片血管旁假菊形团结构,尸检标本起自四脑室底,44/64,Imaging Findings,Ependymoma 室管膜瘤,等密度或稍高密度其内常有点状钙化及低密度囊变无瘤周水肿，周围可见CSF间隙均匀明显强化,CT,45/64,Imaging Findings,Ependymoma 室管膜瘤,T1WI等-低信号，T2WI高信号生长时间长，可发生钙化或囊性变，其T1WI及T2WI的信号不均匀中脑导水管扩张-“茄荚征”起源于四脑室底，因此常将四脑室推向后部呈裂隙状无瘤周水肿，周围可见CSF间隙明显强化,MRI,46/64,Imaging Findings,Ependymoma 室管膜瘤,MRI,茄荚征,47/64,Imaging Findings,Ependymoma 室管膜瘤,MRI T2WI（A）示四脑室区高信号为主的异常信号（），矢状面T1WI（B）肿瘤呈不均匀略低信号（），幕上脑室扩张、积水；增强扫描（C、D）肿瘤呈斑片状明显强化（）,48/64,Imaging Findings,Ependymoma 室管膜瘤,49/64,Imaging Findings,Ependymoma 室管膜瘤,Short TE and long TE MRS of an ependymoma very low levels of NAA and Cr,50/64,Pediatric Neoplasms of the Posterior Fossa -Series topic,MedulloblastomaPilocytic AstrocytomaEpendymomaChoroid Plexus Papilloma and Carcinoma,51/64,Incidence and Clinical Presentation,Choroid Plexus Papilloma 脉络丛乳头状瘤,14岁以下儿童多见于侧脑室发生于四脑室者占儿童CPP的30%脉络丛乳头状瘤（80%）、癌（20%）起源于脑室脉络丛上皮细胞后颅窝的CPP除可见于第四脑室外侧隐窝或第四脑室内外，亦可见于脑桥小脑三角区,52/64,Incidence and Clinical Presentation,Choroid Plexus Papilloma 脉络丛乳头状瘤,Hydrocephalus脑积水overproduction of CSF产生过多impaired resorption of CSF secondary to hemorrhage出血所致的CSF吸收障碍obstruction of normal CSF flow梗阻性脑积水Prognosis预后choroid plexus papilloma: excellent脉络丛乳头状瘤：好choroid plexus carcinoma: less promising脉络丛乳头状癌：差,53/64,Grosslysoft cauliflower-like massesperipheral lobulationsfrequent hemorrhagecyst formationNecrosis and parenchymal invasion,Pathologic Findings,Choroid Plexus Papilloma 脉络丛乳头状瘤,大体观菜花状软组织肿块周围分叶常有出血囊变坏死及周围组织侵犯,54/64,Histologic examination: choroid plexus papillomas脉络丛乳头状瘤镜下观quite similar to normal nonneoplastic choroid plexus tissue与正常脉络丛组织类似fibrovascular connective tissue surrounded by columnar or cuboidal cells柱状及立方细胞环绕纤维血管结缔组织without significant mitotic activity核分裂像少见,Pathologic Findings,Choroid Plexus Papilloma 脉络丛乳头状瘤,55/64,Histologic examination: choroid plexus papillomas脉络丛乳头状瘤镜下观,柱状及立方细胞环绕纤维血管结缔组织,56/64,Histologic examination: choroid plexus carcinoma脉络丛乳头状癌镜下观hypercellularity, nuclear pleomorphism细胞密度高，核异型多见high nucleuscytoplasm ratio核浆比高conspicuous mitotic activity核分裂像多见invasion into the adjacent brain parenchyma易侵犯周围脑组织,Pathologic Findings,Choroid Plexus Papilloma 脉络丛乳头状瘤,57/64,Histologic examination: choroid plexus carcinoma脉络丛乳头状癌镜下观,Poorly differentiated choroid plexus carcinoma. Area of vascular endothelial proliferation and thickening of a connective tissue septum.,58/64,Pathologic Findings,Choroid Plexus Papilloma 脉络丛乳头状瘤,Transformation of papilloma to carcinoma: uncommonly脉络丛乳头状瘤与脉络丛乳头状癌的转化：少见CSF seeding: both could occur脑脊液播散： 均可发生,59/64,nonenhanced CT studiesiso- to hyperdensity intraventricular masses等低密度脑室内肿块without brain invasion无明确周围组织侵润Hydrocephalus is very common常见脑积水Calcification: uncommon钙化：少见CPA extension: characteristic feature桥小脑角区侵犯：特征性表现,Imaging Findings-CT,Choroid Plexus Papilloma 脉络丛乳头状瘤,60/64,Imaging Findings-CT,Choroid Plexus Papilloma 脉络丛乳头状瘤,Contrast-enhanced CT scan showing the tumor obviously enhanced, as well as CPA extension.,61/64,On MR imagingT1WI: iso- to hypointense intraventricular massT1WI：等低信号T2WI: variable T2WI： 多样intense enhancement明显强化Flow voids: common常见流空血管Post-contrast MR imaging of the spine: exclude the possibility of seeding诊断脉络丛乳头状瘤/癌后，须行全脊柱检查除外CSF转移,Imaging Findings-MRI,Choroid Plexus Papilloma 脉络丛乳头状瘤,62/64,Imaging Findings-MRI,Choroid Plexus Papilloma 脉络丛乳头状瘤,Preoperative T1-weighted contrast-enhanced magnetic resonance imaging (MRI) of the posterior fossa showing a fourth ventricle mass (A) and postoperative MRI showing total removal of tumor (B). MRI taken 6 years after operation showing a recurrent tumor (C) and spinal drop metastasis at the level of the L3-S1 vertebra (D).,Spinal drop metastasis of posterior choroid plexus papilloma,63/64,Imaging Findings-PET,Choroid Plexus Papilloma 脉络丛乳头状瘤,A: Axial T1-weighted MR image showing a right cerebellopontine angle tumor as iso-intensity. B: MR image with gadolinium showing enhancement. C: PET with 18F-fluoro-2-deoxy-D-glucose (FDG) showing low glucose consumption in the tumor. 葡萄糖代谢正常D: PET with methionine showing high amino acid consumption in the tumor. 蛋氨酸代谢增高,64/64,Aberrations differ significantly between choroid plexus papillomas and choroid plexus carcinomas脉络丛乳头状瘤及癌之间存在明显基因差异pediatric and adult choroid plexus papillomas儿童与成人脉络丛乳头状肿瘤存在明显基因差异indicating: distinct genetic pathways may be involved in the development of these tumors提示基因差异可能参与本病的发生,Chromosomal Imbalances in Choroid Plexus Tumors,Choroid Plexus Papilloma 脉络丛乳头状瘤,65/64,SUMMARY,66/64,67/64,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,PART TWOAdult Tumorsof the Posterior Fossa,68/64,Incidence and Clinical Presentation,Hemangioblastoma 血网,1 to 2.5% of all CNS tumors占所有中枢神经系统肿瘤的1到2.5% 7% of those arising within the posterior fossa占所有后颅窝脑肿瘤的7% vast majority (75%) in the cerebellum, spinal cord (20%)多见于小脑半球，也可见于脊髓always located peripherally, near the cerebellar pial surface常位于小脑半球周边部位，近软脊膜下Males are slightly more commonly男性略常见,69/64,Incidence and Clinical Presentation,Hemangioblastoma 血网,Clinical manifestations临床症状increased intracranial pressure颅内压增高症状Headache, nausea, vomiting, ataxia头痛、恶心、呕吐、共济失调long clinical course (average, 25 weeks)临床病史较长Polycythemia occurs in about 20% of cases肿瘤可分泌促红细胞生成素，导致RBC升高,70/64,Hemangioblastoma and von Hippel-Lindau,Hemangioblastoma 血网,Hemangioblastoma is the most frequent manifestation of VHL血网是最常见的VHL表现类型VHL: autosomal dominant phakomatosisVHL为常染色体显性遗传斑痣性错构瘤病1/3 hemangioblastoma establish the diagnosis of VHL1/3的血网病人见于VHL80% of all VHL patients will have hemangioblastoma80% 的VHL病人有血网diagnosis of VHL disease VHL的诊断Hemangioblastoma, and one other VHL-associated tumor (retinal hemangioblastoma, benign cysts, benign or low-grade tumors, malignant tumors) , or family history血网及其它VHL相关肿瘤（如视网膜血网、良性囊肿、良性或低级别肿瘤或恶性肿瘤），或家庭史,71/64,Pathologic Findings,Hemangioblastoma 血网,agrade I tumor in the WHO classificationWHO 1级肿瘤well-circumscribed mass, lacks a true capsule边界清楚，无真正的囊壁cystic component + smaller highly vascular nodule囊性成份及实性结节cyst wall: compressed brain parenchyma or reactive neuroglial cells囊壁：受压脑组织或反应性胶质细胞,72/64,Pathologic Findings,Hemangioblastoma 血网,Low-power view of a hemangioblastoma, showing large vascular channels (open arrows) and cystic changes (closed arrows). The tumor is well circumscribed against a rim of adjacent compressed cerebellar cortex (arrowheads).,73/64,Pathologic Findings,Hemangioblastoma 血网,1. large lipid-filled vacuolated stromal cells 较大的空泡状间质细胞the neoplastic component of the lesion肿瘤的实性部分2. abundant capillary network丰富的毛细血管网络propens