视网膜母细胞瘤影像学表现

视网膜母细胞瘤（retinoblastoma，RB）,解剖,眼球：包括眼球壁和眼球内容。眼球壁：由外向内依次为巩膜、脉络膜、视网膜。前部为角膜、虹膜、睫状体。眼球内容包括房水、晶状体、玻璃体。,视网膜（retina）居于眼球壁的内层，是一层透明的薄膜,大体分层,色素上皮层,视网膜感觉层,两层间在病理情况下可分开，称为视网膜脱离,视网膜功能,视锥细胞（感受强光、色彩）,视杆细胞（感受弱光）,视神经节细胞等,概述,来源于视网膜内颗粒层细胞。有遗传性（40）一部分有家族史，一部分为合子形成过程中突变所致非遗传性（60 ）为体细胞突变所致视网膜母细胞瘤基因（RB）位于13号染色体1区4带，是一种抗癌基因,流行病学表现多见于5岁以下儿童，绝大多数三岁以内发病RB是学龄前儿童最常见眶内恶性肿瘤成年人和中老年人罕见无种族和性别差异单侧发病为多，双侧发病约30 -40 ,病理,肉眼观肿瘤为灰白色或黄色的结节状肿物，切面有明显的出血及坏死，并可见钙化点镜下见肿瘤由小圆形细胞构成，常只见核而胞浆不明显。核圆形、深染、核分裂像多见。有的瘤细胞停围绕一空腔作放射状排列，形成菊形团,临床表现,典型表现为“白瞳症”，眼底见灰白色或黄白色半球形肿物。青光眼；（肿瘤导致前房角阻塞，眼压升高）眼球增大、突出。,影像学分期,眼球内期：表现为肿瘤局限于眼球内。青光眼期：局限于眼球内同时伴眼球增大。眶内期：肿瘤穿破巩膜形成框内肿瘤或侵犯视神经。（局限于眶内）眶外期：病变已蔓延至眼眶外、沿着视神经侵犯颅内，或已有转移。,影像学表现,CT表现：(RB首选CT检查）眼球玻璃体内后部肿块样高密度影瘤内可见斑点、斑片或者团块状钙化，文献报道钙化发生率90以上。（这种钙化是因为瘤体血供不足导致部分组织坏死，产生钙化复合体）CT值通常大于100Hu以上，增强可见未钙化瘤体不同程度强化,内生性RB常表现为眼球内肿物影，无视网膜剥离。外生型RB往往合并视网膜剥离。肿瘤侵及视神经时,视神经增粗；肿块较大时向前侵犯,晶状体移位、破坏、消失,并侵犯前房；颅内侵犯主要表现为脑室、脑池等处肿块。转移一般不常见，多循血路转移至骨、肝、肺、肾等处。淋巴道转移只在眼眶软组织被累及时才发生，多转移到耳前及颈淋巴结,1岁，女,2岁，男,MRI表现：T1WI呈低或中等信号，T2WI呈中等或高信号，增强后显著强化钙化较多时，病灶内可见长T1、短T2信号；MRI能清晰显示视神经及颅内受侵犯情况。并可早期显示视神经浸润，表现为视神经增粗，增强显示明显强化,Fig.1 Six-year-old male patient with flat-shaped retinoblastoma; non contrast T1-WI with a moderately hyperintense tumor also showing an isointense retinal detachment in the temporal part (a), after application of contrast medium there is an enhancement in the nasal as well as in the temporal part of the expanded mass (b), in T2-WI the subretinal fluid and the vitreous body have identical signal intensities (c) (T=retinoblastoma, F=subretinal fluid, V=vitreous body, L=lens, O=optic nerve, C=choroid, R=retina),Seven-month-old male patient with a mound-shaped retinoblastoma; plain T1-WI with moderately hyperintense tumor (a); after application of contrast medium a sharp demarcation of the choroid to the retinoblastoma (b); T2-WI with small defined retinal detachment with subretinal fluid delineated by the retina (c) (T=retinoblastoma, F=subretinal fluid, V=vitreous body, L=lens, O=optic nerve, C=choroid, R=retina),鉴别诊断,眼球肿瘤脉络膜黑色素瘤脉络膜血管瘤渗出性视网膜炎（Coats病）永存原始玻璃体增生症（PHPV）,脉络膜黑色素瘤多单侧发病，眼底检查视网膜呈棕黑色表现中年多见，男多于女MRI上病变呈短T1短T2信号影。,永存原始玻璃体增生症多发于婴幼儿晶状体与视乳头相连区域蘑 菇样、高脚杯样异常信号，多 呈等或低信号，增强明显强化。玻璃体内可见积液或液液平面CT上无钙化,渗出性视网膜炎多发于6-8岁男童眼球内无肿块视网膜下积液,Coats disease in a 2-year-old boy who presented with strabismus and red eye. Retinal detachment and a whitish mass behind the lens were found on examination of the ocular fundus.,小 结,婴幼儿，多3岁 白瞳症 眼球内肿物伴钙化 但要与好发于婴幼儿的PHPV和Coats病鉴别。,Thank you！,极少数单侧视网膜母细胞瘤患者可