头颈部病例32分析及病例33图像

（原文GaurangShah）建议多朗读英文并口译，小编翻译供参考，愿为您的放射之路锦上添花

A26-year-oldmanpresentswithhistoryofneurofibromatosistype2(NF2)andgradualsensorineuralhearinglossandvertigo.男，26岁，有2型神经纤维瘤病(NF2)病史，并伴有渐进性感音神经性耳聋和眩晕。

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(A)T2-weightedaxialimagingexhibitslowT2signalfillingdefect(arrow)withinthevestibule,extendingintothelateralsemicircularcanalwithpresenceofsimilarlylowT2signalmassfillingupandexpandingtherightinternalauditorycanal(IAC).HighT2signaltrappedfluidisseenatleftpetrousapex.(B)PostcontrastT1axialimagingexhibitsintenseenhancementofrightIACmassandrightintravestibularmass(arrow).(C)PostcontrastT1coronalimageexhibitsintensepostcontrastenhancementofvestibuleandadjoiningsemicircularcanals(arrow).(D)Volumetric3DFIESTAimagingexhibitsalowT2signalfillingdefect(arrow)withinhighT2signalvestibularfluid.

(A)T2WI轴位成像示前庭内低T2信号充盈缺损(箭头)，延伸至外侧半规管，右侧内耳道(IAC)也可见类似的低T2信号团块填充并扩张。左侧岩尖可见高T2信号液体。(B)增强后T1轴位示右侧IAC肿块和右侧前庭内肿块明显强化(箭头)。(C)增强后T1冠状面图像显示前庭及邻近半规管增强后明显强化(箭头)。(D)3DFIESTA容积成像示T2高信号前庭积液内的低T2信号充盈缺损(箭头)。

DifferentialDiagnosis

?IntravestibularschwannomawithacousticschwannomawithintheIAC:IntenselyenhancinglowT2signalintravestibularfillingdefectconformingtothecontourofthemembranouslabyrinthwithoutexpansion.LargermasswithsimilarsignalandcontrastcharacteristicsisalsovisualizedwithintherightIAC.

?Schwannomaoffacialnerve:Lobulatedandtubularexpansilemasswithinintratemporalfacialnervecanalwithsecondaryinvolvementofmembranouslabyrinth.

?Labyrinthitis:Linearenhancementofcochleaandvestibuleonpostcontrastimaging;however,noevidenceofafillingdefectwithinthemembranouslabyrinthonT2-weightedimages.

鉴别诊断

?前庭内神经鞘瘤与IAC内听神经鞘瘤：前庭内明显强化、低T2信号充盈缺损，对应膜迷路轮廓且无扩张。具有相似信号和强化特征的较大肿块也可在右侧IAC内显示。

?面神经鞘瘤：颞叶面神经管内分叶状、管状膨胀性肿块，继发于膜迷路。

?迷路炎：增强后可见耳蜗和前庭呈线状强化，但在T2WI图像上未见膜迷路内充盈缺损的征象。

EssentialFacts

?Slow-growingbenignneoplasmoriginatingfromSchwanncellsalongthedistalcochlearorvestibularnervewithinthemembranouslabyrinth.

?ItmaybepresentinconjunctionwithIAC/cerebellopontineangle(CPA)massesormaystandalone.

?Intravestibularmasspresentswithtinnitus,vertigo,nausea,vomiting,andmixedhearingloss.Intracochlearmasspresentswithslowlyprogressivesensorineuralhearingloss.

?Surgeryperformedonlyincasesofintractabledisablingsymptomslikevertigothatresultintotaldeafness.

重点：

?生长缓慢的良性肿瘤，起源于膜迷路内沿耳蜗远端或前庭神经的施万细胞。

?它可以与IAC/小脑桥脑角(CPA)肿块一起出现，也可以单独存在。

?前庭内肿块表现为耳鸣、眩晕、恶心、呕吐和混合性耳聋。耳蜗内肿块表现为缓慢进行性的感觉神经性耳聋。

?只有在有难治性致残症状如眩晕等导致完全失聪的情况下才需进行手术。

OtherImagingFindings

?IntralabyrinthineschwannomamayhavenormaltemporalboneCTscan.

?OnMRI,lowT2signalmassisvisualizedwithinhighT2signalcochleaorvestibuleasafillingdefect.

?VolumetricT2-weighted3DsequenceslikeFIESTAdelineatealowT2signalmass,contrastedagainsthighT2signalfluidofcochleaandvestibule.

?OnpostcontrastT1-weightedimaging,intensefocalenhancementofintralabyrinthineschwannomaisseen.

其他影像学表现

?迷路内神经鞘瘤的颞骨CT扫描可表现正常。

?MRI上，高T2信号的耳蜗或前庭内可见低T2信号肿块的充盈缺损。

?容积T2加权3D序列(如FIESTA)显示低T2信号团块，与耳蜗和前庭的高T2信号液形成对比。

?增强后T1WI可见迷路内神经鞘瘤病灶强化。

√Pearls×Pitfalls

√NormaltemporalboneCTwithlowT2signalfillingdefectwithinhighT2signalfluidofcochleaorvestibuleonvolumetricT2-weightedimaginglikeFIESTAinapatientwithsensorineuralhearingloss,tinnitus,vertigo,orMénièredisease.

×SubtlyenhancingintralabyrinthineschwannomaisoftenmissedonbrainMRI.

√重点×陷阱

√颞骨CT正常，容积T2加权序列FIESTA显示高T2信号的耳蜗或前庭内低T2信号充盈缺损，患者表现为感音神经性耳聋，耳鸣，眩晕，或梅尼埃病。

×脑MRI上轻微强化的迷路内神经鞘瘤常漏诊。

头颈部病例33

A7-year-oldboypresentswithananteriorneckmass.

1、ImagingFindings？

2、DifferentialDiagnosis？

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