History:A44-year-oldmanpresentsforachestradiographfollowingapositivepurifiedproteinderivative(PPD)skintestfortuberculosis.Patienthasnorespiratoryorconstitutionalsymptoms.
病史：44岁男性，因结核皮肤反应试验PPD阳性行胸部正侧位平片，患者无呼吸系统或全身症状。
Posteroanteriorandlateralchestradiographsareshownbelow.
胸部后前位及侧位片如下所示。
ChestCTandMRIwereattainedforfurthercharacterizationoftheanteriormediastinallesionseenontheradiographs.
平片发现前纵隔病变，进一步行胸部CT和MRI检查。
Findings表现
Chestradiographs:Bestseenonthelateralchestradiographwallisasmoothlymarginatedanteriormediastinalopacityintheretrosternalclearspace,whichmeasuresuptoapproximately4cminlength.Thelungsareclearandwithoutanyevidenceoftuberculosis.Therightparatrachealstripeiswithinnormallimits.
胸部平片：在侧位片上更易发现一边缘光滑的前纵隔阴影，位于胸骨后间隙内，病变长度约4cm，肺野清晰，未见肺结核相关表现。右侧气管旁线位置正常。
ChestCT:Contrast-enhancedaxialandsagittalchestCTimagesdemonstrateawell-circumscribed,oval,hypoattenuatinganteriormediastinallesion,correspondingtotheabnormalityseenonchestradiograph.Thewallofthelesionisthinandnoncalcified.Thelesionistotheleftofmidline,anteriortotheascendingaortaandmainpulmonaryartery.Theadjacentfatplanesbetweenthelesionandtheascendingaortaandmainpulmonaryarteryarepreserved.Thelungsareclear.胸部CT：轴位及矢状位胸部CT增强扫描可见一边界清楚，类圆形，低密度前纵隔病变，可对应胸片上发现的异常。病变壁薄、无钙化，位于中线左侧，位于升主动脉及肺动脉干前方，其间的脂肪间隙尚存在。肺野清晰。
ChestMRI:Thewell-circumscribedanteriormediastinallesionseenonCTdemonstrateshomogeneousT2-andT1-hyperintensecontent,withasmallamountofdependentT2-hypointensecontent,correspondingtolayeringdebris.Onthepostgadoliniumimage,thereisnosignificantmuralenhancementandnoenhancingmuralnodularityorinternalsolidenhancing北京看白癜风好点的医院治疗皮肤白癜风专家
