脂肪肉瘤讀片

讀片病史介紹女，30歲，已婚，漢族；患者于1993年發(fā)現(xiàn)下面部有一外生形腫物，約“紅棗”大小，無痛和其它不適癥狀；患者于2000年在當(dāng)?shù)剡M(jìn)行手術(shù)（具體手術(shù)和結(jié)果不詳），術(shù)后腫塊仍生長；現(xiàn)腫物范圍約10cm×10cm,并突向口腔內(nèi)；發(fā)病期間腫物反復(fù)破潰，并流出毛發(fā)狀物質(zhì)。2查體：頜面部不對稱，左頜面部自顳部至眶下緣至下頜骨下緣，左口角處腫物質(zhì)地硬，左眶下及腮腺咬肌區(qū)腫物質(zhì)地偏軟，左耳垂后腫物質(zhì)地偏硬，腫物邊界不清、活動度差，無觸壓痛；張口受限，張口度1.5cm;左臉頰部隆起，無破潰，表面可見多個橢圓形腫物，質(zhì)地較軟，咬合紊亂345678您的診斷？？9診斷：左下頜去分化脂肪肉瘤大體：左下頜角腫物：灰紅色碎組織一堆，共大小18cm×13cm×4cm,內(nèi)見皮膚、軟組織、涎腺、碎骨和牙齒，部分軟組織切面灰黃色，實(shí)性，質(zhì)韌，內(nèi)含部分鈣化點(diǎn)。鏡檢：腫瘤組織由分化良好的脂肪細(xì)胞構(gòu)成，其間可見怪異核的間質(zhì)細(xì)胞和少數(shù)多泡狀脂母細(xì)胞，部分區(qū)域可見纖維粘液樣基質(zhì)，腫瘤細(xì)胞束狀排列。診斷：（左下頜）去分化脂肪肉瘤，去分化成份為低度惡性肉瘤10內(nèi)容大綱1定義3病理特征5影像病理聯(lián)系24臨床影像表現(xiàn)112012年WHO對脂肪性腫瘤分類良性中間性惡性脂肪瘤非典型性脂肪瘤性腫瘤去分化脂肪肉瘤脂肪瘤病分化良好的脂肪肉瘤粘液性脂肪肉瘤神經(jīng)脂肪瘤病圓細(xì)胞脂肪肉瘤脂肪母細(xì)胞瘤多型性脂肪肉瘤血管脂肪瘤混合型脂肪肉瘤平滑肌脂肪瘤脂肪肉瘤，無其它特異性軟骨樣脂肪瘤腎外血管平滑肌脂肪瘤腎上腺外髓性脂肪瘤梭形細(xì)胞脂肪瘤多形性脂肪瘤冬眠瘤12定義定義脂肪肉瘤（liposarcoma）為起源于脂肪組織的軟組織惡性腫瘤，其細(xì)

胞分化為成脂肪細(xì)胞和脂肪細(xì)胞發(fā)病率：成年人第二位常見的軟組織惡性腫瘤，在軟組織肉瘤中約占20%。但遠(yuǎn)比脂肪瘤少見。性別：男性發(fā)病多于女性，男女發(fā)病之比為4：1年齡：常見于40~60歲的中、老年人，20歲以前很少發(fā)病，兒童罕見13發(fā)病部位病理類型圖1陳代云等國內(nèi)340例統(tǒng)計(jì)資料圖2按病理類型分脂肪肉瘤發(fā)生的比例14臨床表現(xiàn)癥狀與體征：無痛性軟組織腫物，可以非常大，可呈分葉狀，邊界清楚。晚期可出現(xiàn)疼痛和功能障礙,腫物壓迫神經(jīng)、血管可劇痛和肢體水腫。發(fā)生于腹膜后者腫瘤多引起繼發(fā)癥狀。病程：分化好的脂肪肉瘤：手術(shù)切除術(shù)后局部可以復(fù)發(fā)，個別可發(fā)生轉(zhuǎn)移；分化不良的脂肪肉瘤：易迅速出現(xiàn)局部復(fù)發(fā)和遠(yuǎn)處轉(zhuǎn)移。預(yù)后：脂肪肉瘤的預(yù)后根據(jù)其類型、范圍、分級以及治療時機(jī)不同而有所不同，10年生存率為50%。15病理學(xué)改變腫瘤起源于間葉細(xì)胞，由不同分化程度和異形性的脂肪細(xì)胞組成，通常分為5種組織學(xué)類型：高分化型、粘液型、圓形細(xì)胞型、多形性、去分化型。共同特征：脂肪母細(xì)胞——單核或多核，胞漿內(nèi)含有一個或多個空泡，可呈印戒狀或海綿狀。瘤細(xì)胞：成熟脂肪細(xì)胞，具有異型性脂母細(xì)胞、圓形細(xì)胞、梭形細(xì)胞、多核巨細(xì)胞、其發(fā)生部位較深（肌鍵、腹膜后），極少來自皮下脂肪組織，這與脂肪瘤相反——脂肪肉瘤極少從脂肪瘤惡變而來。脂肪肉瘤不是由脂肪組織演變而來，起源于原始間充質(zhì)細(xì)胞，瘤組織內(nèi)含有未分化、不等量的脂肪組織。16病理學(xué)改變?nèi)庋鬯姡撼史秩~狀，有假包膜（分化良好者包膜完整），呈浸潤型生長，主瘤旁可有少數(shù)衛(wèi)星病灶切面：常呈粘液樣或蒼白實(shí)質(zhì)性，細(xì)膩魚肉狀，分化愈好則愈保持脂肪淡黃色的特征性。體積大者往往有繼發(fā)性出血、壞死、囊性變圖3脂肪肉瘤大體標(biāo)本17

高分化型

Well-differentiatedtype圖4高分化型

脂肪肉瘤由大小不等的脂肪細(xì)胞和單泡和多泡的脂母細(xì)胞構(gòu)成圖5粘液型脂肪肉瘤.粘液基質(zhì)背景下散在脂母細(xì)胞、間葉細(xì)胞和叢狀毛細(xì)血管網(wǎng)

粘液型

myxoidliposarcoma18去分化型dedifferentiatedtype圖6去分化脂肪肉瘤白色為去分化部分，黃色為脂肪組織鏡下可見呈梭形細(xì)胞，還可見非典型脂肪細(xì)胞和脂母細(xì)胞去分化型：從高分化型向不同分化程度的非脂肪細(xì)胞性肉瘤的移行，去分化的多少常常肉眼檢查即可明確。鏡下可見呈一致性束狀排列的，細(xì)胞核有輕度異型性的纖維母細(xì)胞性的梭形細(xì)胞，還可見非典型脂肪細(xì)胞和脂母細(xì)胞。19圓形細(xì)胞型

Roundcellliposarcoma圖7圓細(xì)胞型脂肪肉瘤成片未分化的、富含糖原、圓形細(xì)胞和混雜的脂母細(xì)胞），易發(fā)生出血壞死，WHO現(xiàn)將此型歸為粘液性脂肪肉瘤中含有大量圓形細(xì)胞圖8多形性脂肪肉瘤主要有多形性梭形細(xì)胞和巨細(xì)胞、多形性脂母細(xì)胞構(gòu)成，常見不典型的核絲分裂和壞死，惡性程度高，局部復(fù)發(fā)和轉(zhuǎn)移多見多形性型

Pleomorphicliposarcoma20影像診斷X線平片：軟組織腫物：根據(jù)瘤內(nèi)的結(jié)構(gòu)和所含脂肪成分的比例而表現(xiàn)為不同密度的軟組織腫塊，難以分清邊界；高分化偶爾可見到鈣化和骨化;鄰近骨可見到明顯的侵蝕破壞。圖9脂肪肉瘤的X平片21脂肪肉瘤間鑒別分化良好（中性）分化不良（惡性）形態(tài)規(guī)則，少浸潤，邊界清楚內(nèi)部分隔少不規(guī)則，浸潤，邊界不清內(nèi)部分隔多、厚，有出血、鈣化、囊變CT脂肪密度為主，在-80～-120HU之間接近于軟組織的密度MRI脂肪成分為主，T1WI高信號，T2WI高信號根據(jù)病理類型信號有所不同粘液成分為主，表現(xiàn)為T1WI低信號、T2WI高信號增強(qiáng)不強(qiáng)化或輕度強(qiáng)化可見結(jié)節(jié)性或彌漫性強(qiáng)化分隔有強(qiáng)化厚而規(guī)則分隔，顯著強(qiáng)化鄰近結(jié)構(gòu)腫瘤向骨內(nèi)延伸或侵犯鄰近的骨與關(guān)節(jié)表1分化良好與分化不良的脂肪肉瘤間鑒別22Case1:lipomaFig.10a–cIntramuscularlipomaofthethighina61-year-oldwoman.aLargemassinthequadricepsmuscleoftheleftthighwithlowattenuationvaluesonCT.b-c

ThesignalintensityondifferentMRsequencesequalsthatoffat.Note.thepresenceofmultipleintratumoralstrandsofhigherdensityonCT(a)andlowerSI(b,c)onMRI.

CTscanCoronalT1WIAxialT2WI23Case2:lipoma（well-differentiatedliposarcomas）Fig.11a-c

Intramuscularlipomaofthethighina55-year-oldwomanathereisalargemassinthequadricepsmuscle,withSIidenticaltothatoffat,containingirregularlylinearseptaoflowSI,

bthereisareductioninthelesion’sSI,accordingtoitsfattynature,

cAfterintravenousgadoliniumadministration,thereisadistinctenhancementofthesepta.Note:Thesecharacteristicsareveryfrequentlyseeninwell-differentiatedliposarcomas,aswell,makingthedifferentialdiagnosiswithlipomaextremelydif?cult.CoronalT1WISagittalFST1WISagittalFST1WIC+24Case3：Well-differentiatedliposarcomaFig.12a-dWell-differentiatedliposarcomaofthethighina43-year-oldman.MRdisplaysaverywell-de?ned,heterogeneousfattymassintheadductormuscles.

a

ThecentralareaisoflowSIonT1-weightedimage,bhighSIonT2-weightedimage,candintermediateSIonfat-suppressedimage.d

Theenhancementofthiscentralareaiswelldemonstratedonfat-suppressedimageaftergadoliniumcontrast.AxialT2WISagittalT1WISagittalFST1WISagittalT1WI25Case4:myxoidliposarcomaFig.13a-c.Patientwithamyxoidliposarcoma.aAxialSTIRsequenceshowsasharplymarginedmasslesionwithhomogeneoushigh-signal.bAverylowtumor-to-musclecontrastisshown,withthelesion’ssignalintensityslightlylowerthanmuscle.IncombinationwiththehighsignalintensityonSTIRsequence,thislesioncouldbemistakenforacystbasedonunenhancedsequencesalone.cAxial,Gd-enhancedT1-weightedimageshowsade?niteandveryheterogeneousenhancement,inconsistentwithacysticoriginofthelesion.Note.Thissequenceisverysuitableforsurgicalplanning.ThisenhancedT1WIhelpstodifferentiateviabletumorfromacyst,withatotallydifferentsurgicalapproach,andhelpstoselectanappropriatebiopsysite.AxialFST2WIAxialT1WIAxialT1WIC+26Case5:myxoidliposarcomaFig.14a-c.a

Alargepolylobulatedmassisseenintheposteriorcompartmentofthethigh.ThismassisalmosthomogeneousandofverylowSIonT1-WI.b

OnT2-weightedimagethelesionismoreheterogeneousandstronglyhyperintense.c

Enhancedfat

suppressedT1-weightedimagesshowaheterogeneouslesionwithhighSIareasattheperipheryandlowSIareasmorecentrallylocated.SagittalFST1WIC+SagittalT1WIAxial

T2WI27Case6：DedifferentiatedliposarcomaFigure15a-c.Dedifferentiatedliposarcomaintheposteriorcompartmentofthethigh.aAmasslesionisshowninthehamstringsmuscles.bInthispatient,additionalcoronalimagingdemonstratesmarkedextentoftumororperitumoraledemadistallyinthesemitendinosusmuscle,whichisinformationofmajorvaluewhenthe?eldofpreoperativeradiotherapyhastobedelineatedorthewidthofsurgicalresectionhastobedetermined.Sincethemedialhalfofthelesionshowsextensivenecrosis,abiopsyshouldbeobtainedfromtheviablelaterpart.c

Imageshowsperitumoralbrightening(edemaand/ortumorspread)intheadjacentsemitendinosusmuscleSagittalT2WICoronalT1WICoronalT1WIC+28Fig.16a–caThesagittalT1-weightedimageshowsalarge,well-de?ned,slightlyheterogeneoussofttissuemasswithSIsimilartothatofskeletalmuscle.bOnT2-weightedimagethetumordisplayshighSI.cAfterintravenouscontrastadministrationdespitethehigh-gradeofmalignancyofthistumorenhancementishardlyseen,withsomediscretehyperintensefoci.Case7:RoundcellliposarcomaSagittalT1WIAxialT2WISagittalT1WIC+29Case8:PleomorphicliposarcomaFig.17a–dPleomorphicliposarcomaofthethigh.aMostpleomorphicliposarcomapresentasnonspeci?c,heterogeneousmasseswithrelativelywellcircumscribedmargins.

a-bThereisusuallynotasuf?cientamountafatandthereforealowsignalintensityisseenonT1-weightedimages(a)andahighsignalintensityonT2-weightedimages(b).c–dThereisamarkedandheterogeneousenhancementafterintravenouscontrastadministration.AxialT1WISagittalFST2WISagittalFST1WIC+Subtractionimage30Case9:MixedliposarcomaFig.18a,bMixedliposarcoma(myxoid+roundcelltypes)ofthelowerlegina70-year-oldwoman.aMRIdisplaysafusiform,nearhomogeneousmassoflowSIonT1-WI,withoutfattycomponent.b

AfterGd-contrastinjectionthelesiondemonstratesaseptatedappearanceandastrongenhancement,wellseenwithfat-suppression.Note.Thesecharacteristicsarenonspeci?cforalipomatoustumor,butverysuggestiveforasarcomaSagittalT1WISagittalFST1WIC+31小結(jié)：鑒別診斷分化良好（中性）分化不良（惡性）形態(tài)規(guī)則，少浸潤，邊界清楚內(nèi)部分隔少，有出血、鈣化、囊變不規(guī)則，浸潤，邊界不清內(nèi)部分隔多、厚，有出血、鈣化、囊變CT脂肪密度為主，在-80～-120HU之間接近于軟組織的密度MRI脂肪成分為主，T1WI高信號，T2WI高信號根據(jù)病理類型信號有所不同粘液成分為主，表現(xiàn)為T1WI低信號、T2WI高信號增強(qiáng)不強(qiáng)化或輕度強(qiáng)化可見結(jié)節(jié)性或彌漫性強(qiáng)化分隔有強(qiáng)化厚而規(guī)則分隔，顯著強(qiáng)化鄰近結(jié)構(gòu)腫瘤向骨內(nèi)延伸或侵犯鄰近的骨與關(guān)節(jié)表1分化良好與分化不良的脂肪肉瘤間鑒別32小結(jié)：鑒別診斷LipomaIntramuscularlipomaLiposarcomaAgeadult(mean52years)adultadult(mean65years)LocationSuperficiallylocated(subcutaneousfat)Back,shoulder,neck,arm,thigh,abdomenMuscleThigh,shoulder,armMuscles/FasciasThigh,retroperitoneumSize<5cm(80%)<10cm(95%)frequently>5cmexceptionally<5cmMarginsWell-definedInfiltratingorwelldefinedUsuallywelldefinedShapeUninodularUninodular(>85%)Multinodular(>90%)SeptaornodulesAbsentor<2mmHypoonFST2-W1NoorweakenhancementIntermingledmusclefibers

Isointensetomuscle

EnhancementrareThick(>2mm)

HyperonFST2-WI

Strongenhancement表2脂肪瘤和脂肪肉瘤間鑒別ChengL.AtlasofSoftTissueTumorpathology[M].SpringerUK.2013:1-1633小結(jié):影像診斷的優(yōu)勢與難點(diǎn)優(yōu)勢鑒別良惡性、判斷預(yù)后為手術(shù)術(shù)式選擇提供參考：如case4為放療、穿刺等精確定位提供參考：如case5難點(diǎn)分化好的脂肪肉瘤與脂肪瘤的鑒別較難：如case2、3含有脂肪成分的其他間葉組織腫瘤較難鑒別：

如Case934參考文獻(xiàn)1. ChengL.AtlasofSoftTissueTumorpathology[M].Springer，UK.2013:1-16.2. SchepperAMD,VanhoenackerF,J.Gielen,P.M.Parizel.ImagingofSoftTissueTumors3rded[M].Springer，USA.2006:167-227.3. PiperiE,TosiosKI,NikitakisNGetal.Well-DifferentiatedLiposarcoma/AtypicalLipomatousTumoroftheOralCavity:ReportofThreeCasesandReviewoftheLiterature.HeadandNeckPathology.2012;6(3):354-63.4. YamauchiJ,UbaraY,IkedaK,etal.Retroperitonealliposarcomawithlamellarboneinside.TheLancet.2011;377(9769):941.5. ChengJ,WangY,ChengA,etal.Pr