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  433 Progressin Barrett’sEsophagus: ARadiologic Radiology Diagnosis? MarcS.Levine1Barrett’sesophagusisawell-recognizedconditioncharacterizedbyaprogres-sivecolumnarmetaplasiaofthedistalesophaguscausedbychronicrefluxesoph-agitis.Despiteitsfrequency,Barrett’sesophaguswouldnotbeimportantifitwereabenignentity.However,thereisnowconsiderableevidencethatitisapremalig-nantconditionassociatedwithasignificantlyincreasedriskofdevelopingesopha-gealadenocarcinoma.Unfortunately,thediagnosisofBarrett’sesophagushasbeenlimitedonbariumstudiesbyalackofclearlydefinedradiologiccriteriathatarebothsensitivetoandspecificforthiscondition.Asaresult,endoscopyandbiopsygenerallyhavebeenadvocatedinordertomakeadefinitivediagnosis.However,recentdatasuggestthatdouble-contrastesophagographymaybeavaluabletechniqueindeterminingtherelativeneedforendoscopyandbiopsyinpatientswithrefluxdisease.ThecurrentstatusofBarrett’sesophagusisthereforereviewedinthisarticle,withparticularemphasisontheroleofradiologyindiagnosingthiscondition. PathogenesisandPrevalence BarretthimselforiginallyhypothesizedthattheunderlyingabnormalityinBarrett’sesophaguswasacongenitallyshortesophaguswithanattenuatedintrathoracicstomachmasqueradingasthecolumnar-linedloweresophagus[1 ]. Subsequently,itwaspostulatedthatthisconditionresultedfromabnormalembryologicdevelop-mentwithincompletesquamousreepithelializationofthecolumnar-linedfetalesophagus[2].However,thereisnowconsiderableevidencethatBarrett’sesoph-agusisalmostalwaysanacquiredconditionwithprogressivecolumnarmetaplasiaofthedistalesophagusduetolong-standinggastroesophagealrefluxandrefluxesophagitis[3-8].ItisunclearwhysomepatientswithrefluxesophagitisdevelopBarrett’sesophagusandothersdonot.Nevertheless,recurrentepisodesofulcerationduetochronicrefluxesophagitisapparentlymaycausethenormalsquamousepitheliumintheesophagustobedenudedandsubsequentlyreplacedbyacolumnarepitheliallining.Recentdatasuggestthatthisconditionismorecommonthanhaspreviouslybeenrecognized.Invariousstudies,theprevalenceofBarrett’sesophagusinpatientswithrefiuxesophagitishasrangedfrom8 to20 ,withanoverallprevalenceofabout10 [9-12].ThisfiguremaybeskewedinfavorofBarrett’sesophagus,becausepatientswithrefluxsymptomswhoundergoendoscopyare Received Apnl6,1988; accepted afterrevision ... May17, 1988. likelytohavesignificantrefluxdisease.Nevertheless,Barrettsesophagusisbeing ‘DepartmentofRadiology,Hospitalofthe   diagnosedwithgreaterfrequencyasthenumberofpatientswhoundergoendos- versityofPennsylvania,3400 Spruce St., Ptiiladel copyincreases. phia,PA19104.AddressreprintrequeststoM.S. Anassociation between Barrett’sesophagusandsclerodermahasalsobeen Levine. . recognized[13-151.Inarecentstudy,37 ofallpatientswithsclerodermawho  e ber 1988 underwentendoscopyforsymptomsofrefluxesophagitishadbiopsy-proved ©AmericanRoentgenRaySociety Barrett’sesophagus[16].ThehighprevalenceofBarrett’sesophagusinpatients    A  m  e  r   i  c  a  n   J  o  u  r  n  a   l  o   f   R  o  e  n   t  g  e  n  o   l  o  g  y   1   9   8   8 .   1   5   1  :   4   3   3  -   4   3   8 .  434LEVINE AJR:151,September1988 withsclerodermaisprobablyrelatedtothesevereesophagitisthatoccursintheseindividualsasaresultofmarkedloweresophagealsphincterdysfunctionandpoorclearanceofre-fluxedpepticacidfromtheesophagus[17].PatientswhohavesclerodermathereforeappeartobeatevengreaternskfordevelopingBarrett’sesophagusthanareotherpatientswhohaverefluxesophagitis. RelationshiptoAdenocarcinoma Barrett’sesophagusisimportantbecauseitisapremalig-nantconditionassociatedwithasignificantlyincreasedriskofdevelopingesophagealadenocarcinoma.Invariousstud-ies,theprevalenceofadenocarcinomainpatientswhohaveBarrett’sesophagushasrangedfrom2.4 to46.5 ,withanoverallprevalenceofabout15 [9,11 , 12,18-20].Prevalencedatamayexaggeratetheriskofcancer,becausemostpatientswithBarrett’sesophagusdonotseekmedicalattentionuntilcomplicationssuchasulcers,strictures,ormalignancydevelop.Nevertheless,recentstudiesthatusedincidencedataratherthanprevalencedataindicatethattheriskofdevelopingadenocarcinomaisperhaps30-40timesgreaterinpatientswhohaveBarrett’sesophagusthaninthegeneralpopulation[21,22].ThesequenceofeventsleadingtothedevelopmentofadenocarcinomainBarrett’sesophagushasbeenthesubjectofconsiderableinterest.Innumerousstudies,histologicex-aminationofresectedspecimenshasrevealeddysplasiaand/orcarcinoma-in-situwithinBarrett’smucosaadjacenttoorremotefromtheprimarytumor[8,20,23-28].Itthereforeiswidelybelievedthatadenocarcinomaevolvesthroughase-quenceofprogressivelysevereepithelialdysplasia,carci-noma-in-situ,andinvasivecarcinomainpreexistingareasofcolumnarmetaplasia.Thesedysplasticorcarcinomatouschangescanberecognizedbyendoscopicbiopsyorcytology.Thus,manyinvestigatorsadvocateperiodicendoscopicsur-veillancewithbiopsyandcytologyat6-monthoryearlyinter-valsforearlydetectionofcancerinBarrett’sesophagus[5-9,18,24-30].However,itisunclearwhatmeasuresshouldbetakenwhenendoscopyrevealsdysplasiainthesepatients.Althoughthepresenceofhigh-gradedysplasiaorcarcinoma-in-situprobablywarrantsanimmediateesophagectomy,thefrequencywithwhichlow-gradedysplasiaprogressestoin-vasivecarcinomaisuncertain.Thus,manyquestionsremainaboutendoscopicsurveillanceandthesubsequentmanage-mentofpatientswhohaveknownBarrett’sesophagus.Muchlessfrequently,thedevelopmentofcancerinBar-rett’sesophagusresultsfromanadenoma-carcinomase-quencesimilartothatfoundinthecolon.BenignadenomatouspolypshaveoccasionallybeenseeninpatientswhohaveBarrett’smucosa,withorwithoutfocalareasofinvasiveadenocarcinoma[20,31 , 32].Becausemalignantdegenera-tionofadenomatoustissuerepresentsanotherpotentialpath-wayforthedevelopmentofadenocarcinoma,endoscopicresectionofthesepolypsmaydecreasetheriskofcancer.EarlyadenocarcinomasarisinginBarrett’sesophagusmayappearondouble-contrastesophagographyasplaquelikelesionsorasflat,sessilepolypswithasmoothorslightlylobulatedcontour[33].Earlycarcinomasmayalsobemani-festedbyfocalirregularity,nodulanty,flattening,and/orul-cerationoftheesophagealwall(Fig.1A).Thusfar,mostearlylesionsreportedintheradiologicliteraturehavebeendiscov-eredfortuitouslyduringradiologicevaluationofrefluxsymp-toms[33].However,asymptomaticlesionscouldalsobedetectedbyradiologicsurveillanceofpatientswhohaveknownBarrett’sesophagus.Inmyopinion,anoptimalscreen-ingprogramforthesepatientsthereforemightalternatedou-ble-contrastesophagographyandendoscopyat6-monthin-tervalsinthehopesofdetectingearlycancerand/ordysplasiainBarrett’sesophagusattheearliestpossiblestage. Fig.1.-Adenocarcinomainthree patientswhohave Barrett’s esopha-gus. A, Relativelylongpepticstricture indistalesophaguswithirreguiarflat-teningofonewaliof stricture  arrows). Atsurgery,patient hadearlyadenocar- cinemain Barrett’s esophagus with ma {149} iignant involvement confined tomu- cosa(ReprintedfromLevine etal. [33].) B, Advanced,Infiltratinglesionin distalesophagus. C,Polypoldlesion  whitearrow Indistalesophagus,invading stomach. Note how normalanatomic landmarks atcardiahavebeenobliterated and replacedbyirregularareasofulcera-tion  black arrows). Atsurgery,thispa- tienthad a primaryadenocarcinoma arisingin Barrett’s esophaguswithsec-ondarygastricinvolvement.    A  m  e  r   i  c  a  n   J  o  u  r  n  a   l  o   f   R  o  e  n   t  g  e  n  o   l  o  g  y   1   9   8   8 .   1   5   1  :   4   3   3  -   4   3   8 .  AJR:151,September1988 BARRETT’SESOPHAGUS435Likesquamouscellcarcinomas,advancedadenocarcino-masarisinginBarrett’sesophagusmayappeargrosslyasinfiltrating,polypoid,ulcerated,or,lessfrequently,varicoidlesions(Figs.1Band1C)[20,34,35].However,thesetumorscanbedifferentiatedfromsquamouscellcarcinomasbytheirfrequenttendencytoinvadethestomach(Fig.1C).Atonetime,tumorsinvolvingthegastroesophagealjunctionwerealmostalwaysthoughttoariseinthestomachandwereclassifiedasprimarygastriccarcinomasthathadsecondarilyinvadedthelowerendoftheesophagus[36-39].Thus,esophagealadenocarcinomawasthoughttobearareentity.However,recentstudiessuggestthatasmanyas20-50 ofthesetumorsinvolvingthegastroesophagealjunctionariseinBarrett’smucosaandsubsequentlyspreadintothestom-ach[20,34,35].AlthoughBarrett’sesophaguscouldcon-ceivablyoccurasafortuitousfindinginpatientswithprimarygastriccarcinomasinvadingtheesophagus,examinationofresectedspecimenshasusuallyrevealedoneormoreareasofesophagealdysplasiaand/orcarcinoma-in-situadjacenttoorremotefromtheproximalmarginofthetumor[20,23,34].Becauseonewouldnotexpecttofinddysplasticchangesbeyondtheleadingedgeofagastriccarcinomainvadingtheesophagus,thepathologicevidencestronglysuggestsanesophagealoriginoftheselesionswithsubsequentspreadintothestomach.Whenthesecaseshavebeenclassifiedcorrectly,adenocarcinomasarisinginBarrett’smucosaac-countfor5-20 ofallesophagealcancers[20,35].Thisdiseasehasthereforebecomeanimportantprobleminmod-emmedicalpractice. ClinicalAspects Barrett’sesophagusmayoccurinadultsofallagesbutismorecommoninolderindividualswithlong-standingrefluxesophagitis.Thereisnoapparentsexpredilection.Theseindividualsmaybeasymptomatic,theymayhavereflux-relatedsymptoms(i.e.,heartburn,substemalchestpain,andregurgitation)orlow-gradeuppergastrointestinalbleedingduetounderlyingrefluxesophagitis,ortheymayhavedys-phagiaduetothedevelopmentofbenignstrictures[4,5].Asthesesuperimposedstricturesprogress,dysphagiamaybe-comethedominantclinicalfeatureandrefluxsymptomsmaycompletelydisappear.Thedevelopmentofadenocarcinomaisnotconfinedtothemiddle-agedorelderlypatientwithBarrett’sesophagusbutmayoccurinyoungpeoplewiththisdisease[18,20,29].Cliniciansthereforeshouldnotbelulledintoafalsesenseofsecurityaboutthepossibilityofmalignancybecauseofthepatient’sage.Themostcommonpresentingfindings(i.e.,dysphagia,weightloss,anduppergastrointestinalbleeding)maybeindistinguishablefromthoseofpatientswithrefluxesophagitisorbenignpepticstrictures.However,patientswithadenocarcinomaarisinginBarrett’sesophagusfre-quentlyhavelong-standingrefluxsymptoms,suchasheart-burnandregurgitation,sothatanyindividualwithchronicrefluxsymptomsshouldbefollowedcloselyforthedevelop-mentofBarrett’sesophagusandsubsequentadenocarci-noma. EndoscopicandHistologicDiagnosis InBarrett’sesophagus,thesquamocolumnarmucosaljunc-tionislocatedabovetheproximalborderoftheloweresoph-agealsphincter,andthecolumnarmucosacanextendproxi-mallyasacontinuoussheet,fingerlikeprojections,orisolatedislandsofcolumnarepithelium[8].TheseislandsofBarrett’smucosamaybeseparatedfromthegastroesophagealjunc-tionbyresidualareasofnormalsquamousepithelium,sothatrandombiopsiesofthedistalesophaguscanbemisleading.AlthoughBarrett’smetaplasiaisoftenconfinedtothedistalthirdoftheesophagus,itmayextendasfarproximallyastheaorticarch.TheendoscopicdiagnosisofBarrett’sesophagusisbasedoncharacteristicchangesinthetextureandcoloroftheepithelium,asBarrett’smucosatypicallyhasavelvety,pink-ish-redappearanceincontrasttotheflat,relativelypaleappearanceofthenormalsquamousepitheliumabove.Al-thoughbiopsiesarerequiredforadefinitivediagnosis,endos-copyhasasensitivityofgreaterthan90 indiagnosingBarrett’sesophagussolelyonthebasisoftheendoscopicappearance[40,41].Histologically,thecolumnar-epitheliallininginBarrett’sesophagusisnotsimplygastricmucosabutamosaicofintimatelyadmixedglandularandcelltypesfromthestomachandsmallbowel,indudingagastric-fundictypeepitheliumwithparietalandchiefcells,ajunctionaltypeepitheliumwithcardiacmucousglands,andaspecializedcolumnarorintes-tinaltypeepitheliumwithavilliformconfiguration,mucousglands,andintestinal-likegobletcells[23,42].Thelatterepitheliumisparticularlyimportant,becauseitpermitsBar-rett’smucosatobedifferentiatedunequivocallyfrommad-vertentgastricbiopsies.Oneormorefocioflow-orhigh-gradedysplasia,carcinoma-in-situ,orinvasivecarcinomamaybepresentinBarrett’smucosa.However,someinvestigatorsbelievethattheriskofmalignantdegenerationisgreatestinpreexistingareasofintestinalmetaplasia[26]. RadiologicDiagnosis TheclassicradmologicfeaturesofBarrett’sesophaguscon-sistofahighesophagealstrictureorulcerassociatedwithaslidinghiataiherniaand/orgastroesophagealreflux[4,43-45].Theunusuallocationofthesestricturesandulcershasbeenattributedtothefactthattheyoftenoccurinthemostproximalsegmentofcolumnarepitheliumatornearthesquamocolumnarjunction[44].However,othershavefoundthatstricturesmayoccurinsquamousepitheliumabovethelevelofthesquamocolumnarjunction[45].Whatevertheirpreciselocation,thepathologicbasisofthesestricturesisuncertain.HighstricturesinBarrett’sesophagususuallyappearradio-graphicallyasringlikeconstrictionsorassmooth,taperedareasofnarrowinginthemidesophagus(Fig.2)[43].So- called “Barrett’sulcers”tendtoberelativelydeepulcercraterswithinBarrett’smucosaataconsiderabledistancefromthegastroesophagealjunction(Fig.3)[46].Whensuchstricturesorulcersaredetectedinpatientswithslidinghiatalhernias    A  m  e  r   i  c  a  n   J  o  u  r  n  a   l  o   f   R  o  e  n   t  g  e  n  o   l  o  g  y   1   9   8   8 .   1   5   1  :   4   3   3  -   4   3   8 .  Fig. 2.-A and B, Barrett’s esophaguswithhighstricturesappearingas ringlikeconstriction  arrow in A) and asa smooth,tapered areaofnarrow-ing  arrow in B). Whenassociatedhiataihernia, gastroesophagealrefiux,and/orrefluxesophagitis are present,Barrett’sesophagusshouldbestronglysuggested. 436LEVINE AJR:151,September1988 and/orgastroesophagealreflux,aconfidentdiagnosisofBar-rett’sesophaguscanbemadeonradiologicgrounds.How-ever,recentstudieshavefoundthatstricturesareactuallymorecommoninthedistalesophagusandthatthemajorityofcasesdonotfittheclassicdescriptionofahighstrictureorulcer[47-50].Thus,esophagographyisaninadequatescreeningexaminationwhenthediagnosisisrestrictedtopatientswhohavetheclassicradiologicfeaturesofthiscondition.AreticularmucosalpatternhasrecentlybeendescribedasarelativelyspecificsignofBarrett’sesophagusondouble-contrastesophagography,particularlyiflocatedadjacenttoastricture[48].Thisreticularpatternischaracterizedradio-graphicallybyinnumerable,tinybarium-filledgroovesorcrev-icesontheesophagealmucosa,oftenresemblingtheareaegastricaepatternfoundondouble-contraststudiesofthestomach.Inmostcases,thereisanadjacentstrictureinthemidor,lessfrequently,distalesophagus,withthereticularpatternextendingdistallyashortbutvariabledistancefromthestricture(Fig.4)[48].Whenpresent,thisfindingshouldbehighlysuggestiveofBarrett’sesophagus,andendoscopyandbiopsyshouldbeperformedforadefinitivediagnosis.However,thisfindinghasbeenobservedinonly5-30 ofpatientswithBarrett’sesophagus[45,48-51],anditsspec-ificityhasalsobeenquestioned[52].Thus,themajorityofcasesofBarrett’sesophaguswillbemissedondouble-contrastesophagographyifareticularmucosalpatternisusedastheprimaryradiologiccriterionfordiagnosingthiscondition.BecauseBarrett’sesophagusdevelopsasthesequelaoflong-standingrefluxesophagitis,itisnotsurprisingthatthesepatientsoftenhaveradiologicevidenceofhiatalhernias,gastroesophagealreflux,refluxesophagitis,and/orpepticstrictures(Fig.5)[44,45,47-51].Inonestudy,97 ofpatientswithBarrett’sesophagushadesophagitisorstric-turesondouble-contrastesophagrams[45].However,thesefindingsfrequentlyoccurinpatientswithuncomplicatedrefluxdisease.Asaresult,inclusionofthesefindingsascriteriaforBarrett’sesophagusincreasesthesensitivityoftheradiologicexaminationbutdecreasesitsspecificity,sothatmanypa-tientswouldbereferredunnecessarilyforendoscopyandbiopsy[51].Thus,radiographicfindingsthatarerelativelyspecificforBarrett’sesophagusarenotsensitive,andthosethataresensitivearenotspecific.Manyinvestigatorsthere-forebelievethatesophagographyhaslimitedvalueasascreeningexaminationforBarrett’sesophagusandthaten-doscopyandbiopsyarerequiredtodiagnosethiscondition.Recently,however,Gilchristetal.[53]performedablinded,retrospectivestudyin200patientswhohadbothdouble-contrastesophagramsandendoscopybecauseofsevererefluxsymptoms.Thepatientswereclassifiedintohigh-,moderate-,andlow-riskgroupsforBarrett’sesophagusonthebasisoftheradiographicfindings.PatientswereclassifiedashighriskforBarrett’sesophagusiftheradiographsre-vealedahighstrictureorulcerorareticularmucosalpattern,atmoderateriskiftheradiographsrevealedadistalpepticstrictureand/orrefluxesophagitis(becausepreviousstudieshaveshownthatabout45 ofpatientswithpepticstrictures[54]and10 withrefluxesophagitis[9-12]haveBarrett’sesophagus),andatlowriskifnoneofthesefindingswerepresent.Whentheseradiologiccriteriawereused,10patients(5 )werethoughttobeathighrisk,73(37 )atmoderaterisk,and117(58 )atlowriskforBarrett’sesophagus.Endoscopiccorrelationrevealedbiopsy-provedBarrett’smu-cosainnine(90 )of10patientsathighrisk,in12(16 )of73atmoderaterisk,andonlyone(<1 )of117atlowriskforBarrett’sesophagus.Althoughtheoverallsensitivityindiagnosingrefluxesoph-agitiswasonly53 ,mostofthecasesofrefluxesophagitisthatweremissedradiographicallyweremild,andonlyoneofthosepatientshadBarrett’sesophagus.ThedatasuggestthatesophagitisthatissevereenoughtocauseBarrett’sesophaguscanalmostalwaysbedetectedontechnicallyadequatedouble-contrastexaminations.Thisobservationhasimportantimplicationsforthemanagementofpatients,be-causeunnecessaryendoscopycanbeavoidedwhenthereisnoradiologicevidenceofesophagitisorstrictureformation.OnthebasisofthestudybyGilchristetal.[53],itseemsreasonabletoclassifypatientsintohigh-,moderate-,andlow-riskgroupsforBarrett’sesophagusbyresultsofdouble-contrastesophagography.PatientswhoareathighriskforBarrett’sesophagusbecauseofahighstrictureorulcerorareticularmucosalpatternshouldundergoearlyendoscopyandbiopsyforadefinitivediagnosis.AlargergroupofpatientsareatmoderateriskforBarrett’sesophagusbecauseof    A  m  e  r   i  c  a  n   J  o  u  r  n  a   l  o   f   R  o  e  n   t  g  e  n  o   l  o  g  y   1   9   8   8 .   1   5   1  :   4   3   3  -   4   3   8 .
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