胰腺囊性病变的影像诊断

CYSTICLEISIONSOFPANCREASPHD.MD.ZHENSHENMATHEIMAGINGDEPARTMENTOFSHANDONGPROVENCEQIANFOSHANHOSPITAL

IntroductionClassificationSystematicApproachMRIversusCT

SmallpancreaticcystsHowtoreportManagement

Pseudocyst

CysticNeoplasms

Ageandgender

Serouscysticneoplasm

MucinousCysticNeoplasma

IntraductalPapillaryMucinousNeoplasm

Main-ductIPMN

Branch-ductIPMN

UncommonNeoplasmswithspecificfindings

SolidPseudopapillaryNeoplasm

NeuroendocrinetumorwithcysticdegenerationClassification

Pancreaticcystscanbecategorizedintothefollowinggroups:PseudocystsCommoncysticneoplasms:IPMN-intraductalpapillarymucinousneoplasmSCN-SerouscysticneoplasmMCN-MucinouscysticneoplasmUncommoncysticneoplasms:SPEN(solidpseudopapillaryepithelialneoplasm)Tumorswithcysticdegeneration:adenocarcinoma-neuroendocrinetumorSystematicApproachWhenacysticpancreaticlesionisdetected,thefirststepistodecidewhetherthelesionismostlikelyapseudocystoracysticneoplasm.Thisschemeisasimplifiedroadmapforthedifferentiationofpancreaticcysts.Pseudocyst–Thinkpseudocystwhenthereisahistoryofpancreatitis,alcoholabuse,stonediseaseorabdominaltraumaandthelesionisunilocularorcontainsnon-enhancingdependentdebris.Cysticneoplasm-Thinkofthepossibilityofacysticneoplasm,whenthereisnohistoryofpancreatitisortrauma,

orwhenthecysthasinternalsepta,asolidcomponent,centralscarorwallcalcification.Mucinouscysticneoplasm-Thisisusually

aunilocularcystfilledwithmucin

sometimeswithwallcalcification,exclusivelyseeninwomen.Serouscysticneoplasm-Thisisamicrocysticlesion,thatconaintsserousfluidwithsometimesacharacteristicscarwhichmaycalcify.Itcanlooklikeabranch-ductIPMN,butSCNhasnocommunicationwiththepancreaticduct.Thetypicalappearancemakesaspecificdiagnosispossible,whichisimportant,becauseSCNistheonlytumorthatisnotpremalignant.Branch-ductIPMN–ThistumorcanlooklikeaSCN,buthasnoscarorcalcifications.MRCPorheavilyweigtedT2WImayshowtheconnectiontothepancreaticduct,whichishighlyspecific.TheleftCT-imageisofapatientwithahistoryofpancreatitis.Therearetwounilocularorsimplecysts.Noticealsotheretroperitonealfat-strandingontheright.Themostlikelydiagnosisispseudocysts.TheCTontherightshowsacystinthepancreatictailina36yearoldwoman,whichwasfoundincidentallywithUS.Thecysthasathickirregularrimandcontainssolid'non-dependent'components.Themostlikelydiagnosisisacysticneoplasm.MRIversusCTCTwilldepictmostpancreaticlesions,butissometimesunabletodepictthecysticcomponent.MRwithheavilyweightedT2WIandMRCPwillbetterdemonstratethecysticnatureandtheinternalstructureofthecystandhastheadvantageofdemonstratingtherelationshipofthecysttothepancreaticductasisseeninIPMN.Theimagesshowaserouscysticneoplasm(SCN).MRIbettershowsthecentralscar(figure).TherearecaseswhenCTcanbehelpful,sinceitbetterdepictsacentralcalcificationinSCNorperipheralcalcificationinamucinouscysticneoplasm(MCN).SCNwithcentralscarseenonMRIMRIisusuallyofmorediagnosticthanCTMRIcanshowthecysticnatureofapancreaticlesionandit'sinternalstructure.TheMRIshowsalargecystwithdependentinternaldebris(figure).PresenceofinternaldependentdebrisappearstobeahighlyspecificMRfindingforthediagnosisofpancreaticpseudocyst(6).MRIshowsdependantdebrisinpseudocystMRIshowsalesion,whichconsistsofmultiplesmallcysts.

Thiscouldbeaserouscysticneoplasmorabranch-ductIPMN.

Theconnectionofthecysticlesiontothepancreaticductindicatesthatthisisabranch-ductIPMN.Smallpancreaticcysts

HowtoreportSmallpancreaticcystshavebeendocumentedinapproximately2.3%ofCTstudiesandupto19%ofMRstudies(11).Mostofthesecystsarefoundinasymptomaticpatients,whoarestudiedforotherreasonsandrepresentbenignorlow-gradeindolentneoplasms.Theabilityofimagingtoenableaspecificdiagnosisofanindividualpancreaticcystislimited,butiseasierinlargercysticlesions.Inmostsmallcystsweshouldnotattempttocharacterizethelesionandwhenwedo,weshouldnotbetooconfident.Themanagementofcysticneoplasmshasnotyetbeenstandardizedandcontinuestoevolve.Accordingtotherecent2021consensusguidelinesbyTanakaetaltheitemsmentionedintheTableshouldbeaddressed(8).ManagementAge,life-expectancyandcomorbidityshouldbeconsideredinthepossiblesurveillanceortreatment.Cystssmallerthan3cmandnoworrisomeorhighrisk-featurescanbeconsideredforfollow-upwitheitherMRI,CTorultrasound.Cystswithobvioushighriskstigmatashouldbeconsideredforresection.ThetableshowstheAmericanCollegeofRadiologyflowchartforimagingofincidentallydiscoveredpancreaticcystsinasymptomaticpatients(11).Pancreaticcystsareregardedsymptomaticwhenthereishyperamylasemia,recent-onsetdiabetes,severeepigastricpain,weightloss,steatorrhea,orjaundice.Pseudocystkeyfindings:Unilocularcystwithoutsolidcomponents,centralscarorwallcalcification.Collectionofpancreaticenzymes,bloodandnecrotictissue.DebriswithinacysticlesionisaspecificMRfinding(6).Historyofpancreatitisorabdominaltrauma.Cystsdevelopin4-6weeks-usuallydecreaseinsizeovertime-sometimesenlargeorbecomeinfected.Foundinanypartofthepancreasoranywherewithintheabdomenandsometimeseveninthechest.TheCTdemonstratesalargecystintheupperabdomeninapatientwhohadanacutepancreatitis.Noticethatthereisalsosomeascitesandpleuralfluid.Therewallenhances.HereanexampleofthevalueofMRIcomparedtoCT.TheMRIshowsdependantdebris(arrow)asadiscriminatorforwalledoffnecrosisinapatientwithapseudocyst.CTdemonstratestwolargecystsina45yearoldwoman,whohadatrauma.Noticesomefatstrandingintheretroperitonealspace(arrow).Theimagingfindingscombinedwiththehistorymakeitverylikelythatthesearetraumaticpseudocysts.Mostpseudocystoccurintheperipancreaticregion,butrarelytheymayextendtothemediastinum.Thispatienthasachronicpancreatitis.Noticethecalcificationsinthepancreatichead(curvedarrow).Therearemultiplepseudocystsextendingallthewaytothemediastinumcompressingtheheart.CysticNeoplasmsThediagnosisofacysticneoplasmshouldbeconsideredwhenthereisnohistoryofpancreatitisortrauma.Morphologicalcharacteristicsofacysticneoplasmare:thickirregularrim,septations,solidcomponents,adilatedpancreaticduct>3mmandcalcifications.FluidaspiratedfromacystwithanamylaselevelInthetablesomediscriminatingfeaturesofcysticneoplasms.Inmanycaseshoweveritisnotpossibletomakeadefinitivediagnosis.Itisimportanttomakethediagnosisofaserouscysticneoplasm,sincethisistheonlytumorthathasnomalignantpotential.Inmanycasesdifferentiationfromabranch-ductIPMNisdifficult,sincebothhavemultiplesmallcysts.AgeandgenderSomecysticneoplasmareseenalmostexclusivelyinwomen,likemucinouscysticneoplasm(99%)andserouscysticneoplasm(75%).Solidpseudopapillaryepithelialneoplasmisanotherpancreatictumorwhichmayhavecysticcomponents.Itisuncommon,butisseenexclusivelyinyoungwomen.Hencethefollowingrule:Grandma-SerouscysticadenomaMother-MucinouscysticneoplasmDaughter-SolidpseudopapillaryepithelialneoplasmSPENSerouscysticneoplasmkeyfindings:Benigntumor,butlargetumorshaveatendencytoincreaseinsizeandcausesymptomsTypicallyseenin'Grandma'Microcysticorhoney-combedcystwithcentralscar(30%)andcalcifications(18%)Macrocysticin10%anddifficulttodifferentiatefrompseudocystandmucinouscysticneoplasmLobulatedsurfaceNocommunicationbetweencystsandpancreaticduct.HypervascularenhancementissometimesseenandcanlooklikecysticneuroendocrinetumorGrowthrateoftumorsGrowthrateoftumors>4cm:upto20mm/ySerouscysticadenomascontainmultiplesmallcystsresultinginalobulatedcontour.Somehaveacentralscarwithcalcifications.Thepathologyspecimenshowsmultiplemicrocysts,whichgivesthetumoralobulatedappearance.Amacrocysticserouscysticneoplasmisrareand,althoughbenign,canbesimilarinappearancetothepotentiallymalignantmacrocysticmucinouscysticneoplasm.CourtesyofDrAllen,HPBsurgery,MemorialSloanKetteringCancerCenter,NYAcharacteristicfeatureofaserouscysticneoplasmisacentralscar,sometimeswithcalcifications.SometimesthemicrocysticcomponentofthistumorisdifficulttoidentifyonCT.MRwillbetteridentifytheinternalarchitecture.MRIisalsousefulindeterminingifthecystscommunicatewiththepancreaticductornottodifferentiatethislesionfromabranch-ductIPMN(seebelow).Thepathologyspecimenshowsacystictumorwithmultiplesmallcystsandacentralscar.Therearenocalcifications.CourtesyofDrKlimstra,pathologyoftheMemorialSloanKetteringCancerCenter,NY,CT-imageofa51yearoldwomanwithahistoryofgallstonesandabdominalpain.Thereisahypodenselesionwithcentralcalcificationintheheadofthepancreas.Thelesionhasalobulatedcontour.ContinuewiththeMR.SerousCysticNeoplasm(SCN)MRIbetterdemonstratesthemorphologicfeaturesofthelesion.OnT2WIthelesionismulticystic.Notethecentrallowsignalduetothecentralscarwithcalcifications.Althoughsomeofthecystsareratherlarge,thisisstillacharacteristicappearanceofaserouscysticadenoma.SerousCysticNeoplasm(SCN)Anotherexampleofaserouscysticneoplasm.Theenhancedimageontherightshowsahypodenselesionwithcentralcalcificationinthebodyofthepancreas.Ontherightimagesubtleenhancementofseptationsareseen.NoticethatonCTitisverydifficulttoappreciatethecysticnatureoftheselesionsandyoumightthinkthatyouaredealingwithapancreaticadenocarcinoma.SerousCysticNeoplasm(SCN)MRIwilleasilydemonstratethecysticnatureoftheselesions.TheT2WIwithfatsatnicelydemonstratesalobuatedhyperintenselesionwithcentralscar,whichischaracteristicofaSCN.SerousCysticNeoplasm(SCN)Itmaybedifficulttodifferentiateaserousmicrocysticadenomafromabranch-ductIPMNorintraductalpapillarymucinousneoplasm.IPMNisalwaysconnectedtothepancreaticduct.T2WIofa71yearoldmanwithahistoryofweightlossandnondescriptupperabdominalcomplaints.Thiswasinitiallythoughttobeabranch-ductIPMN,butturnedouttobeaSCN.Noticethecentralhypointensity.ThisisscartissueinaSCN.Noticealsothecharacteristiclobulatedsurface.Anotherexampleofaserouscystadenoma.Noticethecentralenhancement.Sometimesdifferentiationfromahypervascularcysticneuroendocrinetumorcanbedifficult,butinthiscasethecentralcalcificationsarehelpful.CourtesyKoenraadMortel,DeptRadiology,BrighamandWomen'shospital,BostonInthepancreatictailisacysticlesionwithacentralscarwithcalcifications(arrow).Eventhoughsomeofthecystarelargerthan2cm,thispresentationstillistypicalforaserouscysticneoplasm,becauseofthecentralscar,multilocularappearanceandthelobulatedcontour.Thispatienthadabdominalcomplaintswhichwereattributedtothetumor,whichwasresectedandprovedtobeaserouscysticneoplasm.Serouscysticneoplasm.Thisistheresectedspecimen.Thetumorwasattachedtothespleen,whichalsohadtoberesected.Anothercaseofatypicalserouscysticneoplasm.Thereisamicrocysticlesionwithacentralscarinthepancreatichead.Thispatientfeltamassinherabdomen.Otherwisetherewerenocomplaints.Becauseresectionwouldmeanextensivesurgery,itwasdecidedtofollowthelesion.During5yearfollowuptherewasnogrowthandthepatienthasnosymptomsotherwise.SerouscysticneoplasmMucinousCysticNeoplasmakeyfindings:Premalignanttumor-maytransformintoamucinouscystadenocarcinomaExclusivelyseeninwomen-Typicallyin'Mother'-medianage:40-50yearsMacrocysticwiththickwallseptationsandperipheralcalcificationsPeripheralcalcificationsseenin25%.ThisfindingallowsyoutomakeaspecificdiagnosisLocationinthetailandbodyofthepancreas(95%).Mostaresymptomatic,presentingwithnondescriptabdominalpainCT-imagesofa32year-oldfemalewithpainintheupperleftquadrantradiatingtotheback.Thereisalargecystinthepancreatictailwithperipheralcalcification.Thereissubtleseptationasseenontheleftimageandwallthickening.Youmayhavetoenlargetheimagetoseetheseptation.AspecificdiagnosisofaMCNcanbemade.IntraductalPapillaryMucinousNeoplasmkeyfindings:Mucineproducingtumorinmainpancreaticductorbranch-duct.Location:pancreatichead>>tailandcorpus.Musthavecommunicationwithpancreaticduct.BestseenwithMRCP.Canbemultifocal.Main-ductIPMNhasimagingfeaturesdistinctfrombranch-type.Branch-ducttypecanlooklikeothercysticneoplasmsMacroscopicspecimenofaIPMNshowingmucinoustumor,withextensivemucinproducingpapilaryneoplasm(arrow).Main-ductIPMNOnimagingMain-ductIPMNisdistinctfrombranch-ductIPMN,butsometimesthereisamixedtype.theimagesofalargemainductandbranch-ductIPMN.Thereisobstructionofthecommonbileductwithdilatationoftheintrahepaticbileducts(bluearrows).Noticetheextremelywidenedmainpancreaticduct(redarrow).NormalT2WIandheavilyT2WIwithfatsatofalargemainductIPMNwithextremelydilatedpancreaticduct.Thispatientpresentedwithpancreatitis.TheMRCPshowsbothamain-ductaswellasabranch-ductIPMN(arrow).IPMNisalesionwithmalignantpotential.Signsofmalignancyare:Pancreaticduct>8mm-asinthiscase.Solidnodeinduct.Massaroundthepancreaticduct.Enlargedcholedochalduct.CT-imagesofanIPMNwithadilatedpancreaticduct(bluearrows).Noticeenhancingsolidnoduleinthepancreatichead(redarrow).ContinuewithUS-image.IPMNwithmalignanttransformationTheUS-imageshowsalargebranch-ductcomponentwithinthepancreatichead.Mainductandbranch-ductIPMNBranch-ductIPMNTheCT-imageshowsahypodenselesioninthepancreatichead.Thiscouldbeanadenocarcinoma,butthelowdensitymakesyouthinkofacystictumor.Themicrocysticappearanceraisesthepossibilityofaserouscysticneoplasmalthoughthereisnocalcifiedscar.OnMRCPthecysticnatureisbetterappreciatedandthereisaconnectiontoawidenedduct(bluearrow).Adetailnicelydemonstratesthatsomeofthemucus-filledbranchesareseenincross-sectionandsomelongitudinally.Ina73yearoldmaleahypoechoiclesionwasfoundinthepancreaticbody,thatlookedlikeacysticlesion.CTalsoidentifiesthelesionbutisn'tofmuchhelp.TheheavilyT2WInicelydemonstratesthemulticysticlesionwiththeconnectiontothepancreaticduct,i.e.abranch-ductIPMN.CT-imagesofapatientwithabranch-ductIPMNwhochoosenottohavesurgery.Overtimegrowthofthetumorisseenwithdilatationofthemainductindicatingmalignanttransformation.Sometimesittakes5-8yearsbeforeatransformationisseen.UncommonNeoplasmswithspecificfindingsSolidPseudopapillaryNeoplasmFIRSTSolidPseudopapillaryNeoplasmkeyfindings:Veryuncommonneoplasmseeninwomen20-30years(Daughter).Solidandcysticneoplasmwithcapsuleandwithearly'hemangioma-like'enhancement.SometimesintratumoralhemorrhageCT-imagesofa26yearoldwomanwithalargemassinthepancreaticheadandmetastasesintheliver.Inthecenterthereislackofenhancementduetocysticornecroticdegeneration.Neuroendocrinetumorwithcysticdegeneration

SECONDNeuroendocrinetumorwithcysticdegenerationkeyfindings:Non-functioningendocrineneoplasmAlsocalledisletcelltumorHypervascularwithring-enhancement.Thisisunlikeserouscysticneoplasmsthatenhancefromthecenterandmoresolid)CT-imagesofa61yearoldwomanwithweightloss.Thereisalargemassinthebodyofthepancreasthatishypervascular,unlikeanadenocarcinoma,withsomecysticornecroticparts.CT-imageofaneuroendocrinetumorwithcentralnecrosis.Sometimesthiscansimulateacysticcomponent.Noticetheperipheralenhancement.NeuroendocrinetumorwithcentralnecrosisReferencesTheNaturalHistoryoftheIncidentallyDiscoveredSmallSimplePancreaticCyst:Long-TermFo