色素沉着绒毛结节性滑膜炎的MRI表现

PigmentedVillonodularSynovitis(PVNS)色素沉着绒毛结节性滑膜炎IntroductionPigmentedvillonodularsynovitis(PVNS)comprisesagroupofidiopathiclesionsinjoints,tendonsheathesandbursae.(色素沉着绒毛结节性滑膜炎主要是指关节、滑囊以及腱鞘内的滑膜特发性的呈结节状或绒毛状进行性增生。)Pigmentedvilionodularsynovitis(PVNS)isanuncommon,usuallymonoarticulardisorderandusuallyfoundinadults.Themostcommonsitespredilectionisknee-joint(80%),thenthehip,ankle,shoulder,elbowinturn.(不常见，好发于成年人，生于膝关节,占80%,髋关节、踝关节、肩关节、肘关节的发病率依次减少)ClinicalmanifestationsTheclinicalmanifestationsislackofspecificity.Themainmanifestationsareprogressiveswellingofjointsandhemorrhagicjointeffusion.Itshowsrecurrentjointeffusions,whichcanbemisdiagnosedasarthritis.Episodesofcompleteremissionmaybefoundbetweenperiodsofactivedisease.(本病的临床表现缺乏特异性.临床主要表现为受累关节进行性肿胀,血性关节积液较常见，本病可引起反复积液，各活动期之间可见病变发作的缓解。)ThecauseofPVNSisnotclear,mayberelatedwithtumor、traumaandinfection.(本病的病因尚不明,一般认为与肿瘤、外伤、感染有关。)Diagnosis：imagingfindingsX-ray:theroutineX-rayshowsmajorsymptomsincludingjointcapsuleswelling,softtissuemassinperipheryofjointandinvasionofbonewhichedgeshowsossifiedring,butjointspaceisnormal,noosteoporosis.X线表现:常规X线平片上主要征象包括关节囊肿胀、关节周围软组织肿块及邻近骨骼的侵蚀,骨缺损边缘有硬化环,但关节间隙保持正常,无骨质疏松Diagnosis：imagingfindingsCTfindings:showsjointcapsuleswelling,thickenedsynoviumandobviousjointeffusionCT表现:表现为关节囊肿胀,滑膜增厚,关节腔内明显积液Diagnosis：imagingfindingsMRfindingsisveryspecialandshowsthickenedsynovitisandtheconditionofjointeffusion.MRI表现具有明显的特征性，能清晰的显示滑膜的增厚和积液的程度。Becauseofhemosiderindepositioninthesynovitislesions,itshowslowsignalbothonT1WIandT2WI.Partiallesionsshowboneinvasion.由于病变滑膜组织内含铁血黄素的沉积，故在T1加权像和T2加权像均呈低信号，这是特征性的征象。部分病变可侵蚀骨结构。HistologyandPathology(组织病理学)Thehistologicalfindingsareexuberantsynovialproliferationwithnumerousvilliandfoldsthatsometimesfuseintonodulesandformlocallyaggressiveintra-articularmasses.组织学表现为活跃增生的滑膜呈绒毛状或皱襞样，常形成结节状侵袭性的关节内肿物。PVNScanbedividedintofocaltypeanddiffusetype.PVNS在病理上分为局灶型和弥漫型2种。Diffusetypeshowsexuberantsynovial,villiformproliferationandhemosiderindeposition.Exuberantvilluscandestroyjointcapsuleandsofttissue,andinvadebonebygettingthrougharticularcartilage,junctionofboneandjointortheattachmentofligment.弥漫型主要为滑膜广泛增厚、绒毛状增生和含铁血黄素沉着,增殖的绒毛可破坏关节囊,侵犯周边软组织并通过关节软骨、骨与关节交界部或沿韧带附着处侵犯骨组织Focaltypeshowsmoundsofsynovialcells,dispersedmultinucleatedgiantcells,foamcellsandpigmentedhemosiderindeposition.局灶型为密集成堆的滑膜细胞,间以散在的多核巨细胞和有类脂质积聚的泡沫细胞,以及含铁血黄素沉着。Diffusetype：T2WIshowsmultiplelowsignalnodulesinjointandpoplitealspace,highsignalalsocanbeseeninpartialnoduleswithjointeffusionshowshyperintense.Articularsurfaceoftibialplatformwasinvadedandshowmixedsignalsurroundingbylowsignalring.Lowsignalnodulealsocanbeseeninthesuprapatellarbursa.弥漫型PVNS:T2WI示关节腔内及腘窝多发低信号结节,部分结节内见高信号区,关节腔积液呈高信号。胫骨关节面破坏,呈混杂信号,周围伴低信号环。髌上囊亦见低信号结节.Focaltype：T1WIshowswell-distributedlowsignalmassininfrapatellarbursawithalittleeffusionandjointstructuresisnormal.局灶型PVNS,T1WI示髌下囊内肿块,肿块呈均匀低信号,伴关节腔少量积液,关节骨结构正常Case135-year-oldfemalepatient，progressiveswellingofkneejointsfor5years女，35岁，膝关节进行性肿胀5年Diffusetypeofkneejoint:T1WIshowslowsignalirregularthickenedsynoviumontheanteriorandtheposteriorcruciateligament.膝关节弥漫型PVNS。MRT1WI示前、后交叉韧带表面有不规则增厚的滑膜覆盖,增厚的滑膜呈低信号T2WIalsoshowslowsignalirregularthickenedsynoviumontheanteriorandtheposteriorcruciateligament.Lowsignalnodulescanbeseenintheeffusionofsuprapatellarbursa.T2WIshowsmixedsignalofmultiplebonedestruction,surroundingbyarimofhypointensity.T2WI示前、后交叉韧带表面有不规则增厚的低信号滑膜覆盖,髌上囊积液内见低信号结节(图5)。T2WI示股骨、胫骨多发骨破坏,破坏区高低信号混杂,伴周边低信号环(图6)Case240-year-oldfemalepatient,diffusetypePVNSFigure4:T1WIshowsdiffusivethickenedsynovium.Suprapatellarbursabecomelargebecauseofcloddysynovium.Infrapatellarfatpaddisappearinsteadofproliferoussynovium,anteriorhornofthelateralmeniscuswasinvolved.Figure5:T2WI:diffusiveproliferoussynoviumshowslowsignalbecauseofhemosiderindeposition.MRIT1加权像,滑膜弥漫性增厚,髌上囊因被团状的滑膜组织占据而扩大,髌下脂肪垫内脂肪缺失,代之以增厚的滑膜组织,外侧前角半月板受累及。图5MRI示T2加权像,弥漫增厚的滑膜呈低信号,系含铁血黄素沉积所致。MRIshowsnoduleonthesurfaceofanteriorcruciateligamentandbubblelowsignalunderarticularsurfaceoftibialplatform.Histopathologicsectionshowsproliferoussynovialcell,interstitial(withintissues)showroundnessandpolygon.Partialcellshavehemosiderindeposition,multinucleatedgiantcellscanbeseenlocally.MRI示矢状面T1、T2加权像,前十字韧带表面结节影,胫骨关节面下类圆形低信号骨质缺损。HE×400滑膜细胞明显增生,间质浸润的组织呈圆形或多角形,部分细胞吞噬含铁血黄素,局部见融合的多核巨细胞。Case326-year-oldmalepatient,diffusetypeofrightkneejoint男,26岁,右膝关节弥漫色素沉着绒毛结节性滑膜炎Figure1.T1WI:stratifiedsingularsignalinthepoplitealfossashowsslightlyhighcentreandiso-lowrim.Irregularbandedlowsignalcanbeseeninthesuprapatellarbursaandinfrapatellarfatpad.Obviouslylowsignalcanbeseenbelowthearticularsurfaceoftibia.图1右膝关节矢位T1WI示腘窝内见异常信号,呈中心稍高,周边等、低信号的分层状排列,髌上囊及髌下脂肪囊内见形态不规则的片带状低信号影,胫骨前上缘关节面下见小囊状明显低信号影。Figure2.fat-suppressedT2WI:stratifiedsingularsignalinthepoplitealfossashowsobviouslyhighcentreandiso-lowrim.Irregularbandedhighsignalcanbeseeninthesuprapatellarbursaandinfrapatellarfatpad.Mixedsignalcanbeseenbelowthearticularsurfaceoftibia.图2右膝关节矢位压脂T2WI示腘窝内异常信号,呈中心明显高、周边等、低信号的分层状排列,髌上囊及髌下脂肪囊内见形态不规则的片带状高信号影,胫骨前上缘关节面下见小囊状高、低混杂信号影。figure3.fat-suppressedT1W