毛细胞型星形细胞瘤影像学诊断现状文档资料.ppt
毛细胞型星形细胞瘤(pilocytic astrocytoma,PA)常见于儿童及青少年的良性生长的胶质瘤，好发于深部中线结构，脑干和小脑。1999年WHO将其归于I级星形细胞瘤。由于PA的良性形态学特点、生物学表现与其他星型细胞瘤有很大的区别，临床治疗手段方法也不相同，因此正确的诊断对指导治疗意义重大。,临床特点,生长缓慢、边界清楚的良性肿瘤常出现肿瘤内陈旧性出血、钙化、坏死和淋巴细胞浸润等退行性改变临床表现主要为头痛、头昏伴呕吐等颅内压增高症状，个别患者表现有癫痫，视物模糊，视物双影，月经紊乱，肌张力增高等手术切除效果好，复发及转移率较低，预后良好,病理分型,成年型PA 多见于成人大脑，儿童及青少年脑桥 呈弥漫性生长，易复发幼年型PA 好发于小儿和青年人的小脑、丘脑 生长缓慢，界线清楚,组织学特点,易发生囊变，囊内壁非常光滑，其内充满黄色澄清液体（囊液蛋白质92%以上）由致密排列呈双相性的肿瘤细胞组成含有Rosenthal纤维和嗜酸性小体免疫组织化学检查GFAP、Vim、S2100多为阳性,影像学表现,肿瘤囊壁、壁结节及实性部分CT呈等或稍低密度，T1WI呈等或不均匀低信号，T2WI呈不均匀高信号。肿瘤实性部分及壁结节明显不均匀强化，囊性部分不强化，肿瘤囊壁不强化或轻度强化，囊壁强化提示由肿瘤组织构成,囊液CT平扫呈明显低密度，在T2WI、FLAIR上表现为高信号，比正常脑脊液信号更高根据肿瘤囊性和实性部分的比例及形态可分为4种类型,大囊并壁结节型,Fig.1 Axial T2-weighted image demonstrated a mass with hyperintensity cystic portion compared to the CSF and a high signal intensity mural nodule compared to the gray matter.There was no obvious parenchymal edema.This was the type of mass with cyst and mural nodule.,Fig.2 Contrast-enhanced T1-weighted image showed a cystic solid mass in the seller region.The inferior portion was predominately solid and the superior portion was multi-cyst.The mass was honeycomb-shape enhanced.This was the type of mass with multi-cyst and mural nodule.,多囊并壁结节型,实性型,Fig.3 A:Axial T2-weighted image revealed a rounded heperintense mass with a well-defined margin.There was slightly peripheral edema.B:The mass was homogeneous hypointensity on T1-weighted image,with a well-defineded margin.,C:The mass was homogeneous hyperintensity on FLAIR image.There was slightly peripheral edema.D:The mass was heterogeneous enhanced after administration of contrast medium.This was the type of predominantly solid mass with minimal to no cyst like component.,Fig.4 Gd-DTPA enhanced T1WI showed a cyst-like mass in the midline of the cerebellum.The cyst wall was heterogeneously enhanced with no mural nodule.This was the type of predominantly cystic mass.,完全囊变型,PA特征,儿童和青少年易发病，18岁以下多见好发于小脑蚓部或小脑半球易发生囊变，即呈长T1长T2信号囊壁较光滑，周围边境较清，增强扫描可增强或不增强伴或不伴有瘤壁结节占位效应轻、灶周水肿轻或无,鉴别诊断,PA发生于小脑时主要需与血管母细胞瘤、髓母细胞瘤、第四脑室室管膜瘤相鉴别PA发生于鞍区主需与颅咽管瘤、生殖细胞瘤及侵袭性垂体瘤相鉴别与转移瘤、脓肿相鉴别,血管母细胞瘤,多见于2040岁的成年女性大囊小结节为特征、无钙化或出血、灶周无水肿壁结节强化更明显呈“壁灯征”，囊壁无明显强化，瘤旁常可见到流空的血管壁结节多较小(L0.7cm)多处于中线位置PA囊变更长T1，长T2信号,髓母细胞瘤,也好发于儿童后颅窝肿瘤由高密度细胞组成，T2WI信号与灰质相似，信号不高囊变少见，无壁结节；发生囊变时，囊壁呈不均匀厚壁强化,第四脑室室管膜瘤,可发生在脑室系统的任何部位，以四脑室最多见瘤内出血、坏死液化和钙化常见常于脑室内塑形性生长，侵犯脑实质且瘤周水肿明显T1WI为等或低信号，T2WI上表现为高信号，肿瘤强化不均匀,颅咽管瘤,也是儿童时期的好发肿瘤可为实性、囊性或囊实性，因其内常有囊变、钙化、出血和胆固醇结晶、MR信号呈高低混杂的特点，强化多不均匀临床上常有垂体或下丘脑内分泌异常症状,鞍区生殖细胞瘤,青年女性多见多较小，可呈实性、囊实性，囊性变时呈多囊分格状或蜂窝状，并可沿脑室系统播散常有下丘脑内分泌异常症状对放疗敏感,侵袭性垂体瘤,中心常可见出血、坏死，常见海绵窦受侵，颈内动脉被包绕征象，肿瘤内常有血管流空信号常有垂体内分泌异常症状,转移瘤,好发于老年人，病程短，原发病史瘤内有坏死囊区，无钙化，不均匀环状或不规则结节状强化，周围水肿明显，壁结节明显内突病变可多发，多位于皮髓质交界处发生于小脑的单发转移瘤也可为囊性或囊实性，但瘤周水肿及占位效应明显,脓肿,临床上具有特征的发热表现无壁结节，厚壁环状强化，灶周水肿明显DWI脓液扩散受限呈高信号,谢谢,
