Andersons pediatric cardiology 1320
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HepaticHemangioma
ClinicalFeatures,Investigations,and
Management
Hepatichemangiomasaretechnicallynotarteriovenousmalformations(AVMs),
butratherneoplasmsrepresentingbenignendothelialtumors.4Hepatic
hemangiomascanbebroadlyclassifiedintotwovarieties:congenitaland
infantile.Bothtypesofhemangiomascanexistinextrahepaticlocations,butthe
cardiovascularramificationsexistonlyincasesofhepatichemangioma;hence
ourdiscussionwillbelimitedtohemangiomaspresentingintheliver.Patients
withhepatichemangiomascommonlyhaveassociatedskinhemangiomas,
frequentlymultiple,andtheirpresencemaybetheinitialpresentingfeatureand
shouldpromptasearchforliverhemangioma.Olderliteratureoftenusedthe
termhemangioendothelioma,butthistermwasimpreciseandcouldrepresent
differententities,includingcongenitalorinfantilehemangiomasandeven
malignantangiosarcomas;hencethetermhemangioendotheliomaiscurrently
discouraged.1,5
Congenitalhemangiomaisabenignneoplasmofendothelialoriginthatbegins
proliferatinginuteroandisfullyformedat,orjustbefore,birthandthenfollows
oneofthreepatternsofnaturalevolutiondependingonthesubtype:rapidly
involuting(until15to24monthsofage),partiallyinvoluting,or
noninvoluting.1,6Affectedinfantsmaypresentwithlivermanifestations
(varicealbleeding,hepatomegaly,splenomegaly),hematologicmanifestations
(anemiaandthrombocytopenia),andhigh-outputCHFduetomassive
arteriovenousshunting.Inaddition,cyanosismayoccurduetoright-to-left
shuntingacrossintracardiaccommunicationssuchasanatrialseptaldefector
patentarterialduct.Becausecongenitalhemangiomashavereachedtheirpeak
sizeatbirth,thesevariousmanifestations(e.g.,CHF)areusuallypresent
immediatelyafterbirthifthetumorsarelargeenoughtocausethesesequelae.
Thediagnosisofcongenitalhepatichemangiomaisusuallymadeusing
noninvasiveimaging.Thestudyofchoiceistwo-dimensionalultrasoundwith
Doppler.Theultrasoundappearancecanbevariable,rangingfromahypoechoic
tohyperechoicmass,andlargerhemangiomascanhaveamorecomplex
appearancethatcanincludecalcifications,thrombosis,andfibrosis.7Ifthe
diagnosisisunclear,alivermagneticresonanceimaging(MRI)studywith
contrastanddynamicacquisitionpatterncanbeperformedandtypicallyreveals
ahypointenselesiononT1-weightedandhyperintenselesiononT2-weighted
images.7Congenitalhemangiomasaremostcommonlysingletumors.The
differentialdiagnosisofasolitarylivermasspresentatbirthorshortlythereafter
includeshepatoblastoma,metastaticneuroblastoma,orhamartoma.7However,
typically,hepatoblastomawouldlacktherimenhancementseeninhemangiomas
andwouldbeassociatedwithelevatedα-fetoproteinlevels.Althoughcongenital
hemangiomacanusuallybediagnosedbasedsolelyonnoninvasiveimaging,a
biopsymaybeoccasionallyrequired;itisthereforeimportanttonotethat
congenitalhemangiomadoesnotexpressglucosetransporter-1orlymphatic
markers.8
Congenitalhemangiomacanfollowoneofthreenaturalpatternsofevolution:
rapidlyinvolutingcongenitalhemangiomawilltypicallyinvolutewithinthefirst
24monthsoflife,butmostregressby3monthsofage,9whereasnoninvoluting
congenitalhemangiomawillgenerallynotpersist,andathirdintermediateform
isconsideredtobepartiallyinvoluting.6,10,11
Infantilehemangiomasarethemostcommonofallchildhoodtumorsand
representanentitythatisdistinctfromcongenitalhemangiomas.Infantile
hemangiomascontinuetoproliferateafterbirthandmayreachpeaksizeby6to
12monthsofage,whetherthesearecutaneous,hepatic,orinotherlocations.5
Althoughinfantilehemangiomascanpresentwithverysimilarhematologic,
hepatic,andcardiovascularmanifestationsascongenitalhemangiomas,an
importantdistinctionisthatininfantilehemangiomasthesefeatureswillnotbe
presentatbirthbutmaydevelopduringinfancyifthetumormassreachesa
sufficientsize.Anotherdistinguishingfeatureisthatinfantilehemangiomasmay
expresshighlevelsoftype3iodothyroninedeiodinase,leadingtoinactivationof
circulatingthyroidhormoneandclinicalhypothyroidism.12Itisimportantto
notethatthisformofinfantilehypothyroidismwouldnotbedetectedby
newbornscreeningbecauseitisexpectedtodeveloponlyafterseveralmonthsof
tumorgrowth.
Thediagnosisofinfantileliverhemangiomasisusuallyalsomadebasedon
noninvasiveimaging,usuallyultrasoundwithDoppler,althoughliverMRIalso
playsanimportantrole.Unlikecongenitalhepatichemangiomas,whicharemost
commonlysolitarylesions,infantilehemangiomasaremoreoftenmultifocalor
diffuse.13Althoughbiopsyisnottypicallyrequiredtomakethediagnosis,
infantilehemangiomascharacteristicallyexpressglucosetransporter-1,an
importantandveryspecificdistinguishingfeature.8Theclinicalcourseof
infantilehemangiomaisoneofuniversalgrowthofthetumorupto12monthsof
age,followedbygradualregressionuntilapproximately9yearsorage.
Infantileliverhemangiomasandcongenitalliverhemangiomasofinvoluting
typesmaybeobservedwithouttreatmentinasymptomaticindividuals.Although
asymptomaticinfantsmaybeobserved,theprognosisispoorinuntreatedinfants
presentingwithheartfailure,withanestimated80%to90%mortality.For
patientswithsignificantclinicalmanifestations,suchasCHFand
hypothyroidism,propranolol1to3mg/kgperdayhasbecomethemainstayof
therapyandhasbeenreportedtobeeffectiveforhepaticinfantile
hemangiomas.14,15Thereisnoevidencethatanypharmacotherapyaccelerates
theregressionofrapidlyinvolutingcongenitalhemangiomalesions.14Inthe
past,corticosteroidsandinterferon-αwererecommended,buttheirusehasbeen
supplantedbypropranololduetoitsgreaterefficacyandlowerside-effect
profile.Transcatheterembolization(TCE)maybeoccasionallyrequiredto
controlseveresymptomsuntilpropranololortimeresultinsufficientregression.
Anatomically,theseliverneoplasmsmaypossesshepaticarterialsupply,aswell
asextrahepaticarterialsupplyviathesuperiormesenteric,phrenic,renal,or
intercostalarteries.Inaddition,portalvenoussupplymayalsoexistandhasbeen
correlatedwithincreasedlikelihoodofCHF.7,16Aclearunderstandingofthe
vascularanatomyisnecessarytocarryoutaneffectiveembolization.Surgical
hepaticarteryligationisnowrarelyused.Similarly,surgicalresectionisonly
rarelyrequired,andlivertransplantationisreservedforpatientswithabdominal
compartmentsyndromeforwhomtheremaynotbetimetoallowfor
spontaneousorpharmacotherapy-assistedregression.14
