Andersons pediatric cardiology 1376
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fibrillation.5Allpatientsreferredforsurgeryhadresolutionofarrhythmia
regardlessofwhethersubtotalortotalresectionwasperformed.Ofthethree
nonoperatedpatients,twowerecontrolledonantiarrhythmicmedicationandone
improvedoffmedications.
Successfulsurgicalexcisionoflargetumorshasbeenreportedinchildrenof
allages.Asmentionedpreviously,resolutionofarrhythmiaisseeninnearlyall
cases,eveniftheresectionwasnotcomplete.4,5,31,76,101–104Successful
transplantationofthehearthasalsobeenreportedforchildrenwithcardiac
fibromas.4,101,105,106
Myxomas
Myxomasarethemostcommontypeofcardiactumorsintheoverallpopulation.
Theymakeupapproximately25%ofallprimarytumorsoftheheart,buttheir
incidenceismuchlowerininfantsandchildren.1,5,8,10Theymayhaveafamilial
traitinperhaps5%ofinstances,butmostcasesaresporadic.1,11,107Patientswith
familialmyxomasareyoungeratthetimeofdiagnosis(generallyinthesecond
orthirddecadeoflife)andaremorelikelytohavemultiplemyxomasandhave
associatedsyndromeswithmucocutaneousanomaliesandendocrinopathy
(Carneycomplex).31,107
Cardiacmyxomasaresolitaryin90%to95%ofcases.Thevastmajorityare
atrial,with75%ofalltumorsoriginatingintheleftatrium.11,107Twentypercent
ofmyxomasarerightatrial;althoughthislocationtendstopredominateinfetal
andneonatalseries,wherethemajorityofmyxomaswererightsided.1The
remaining5%ofmyxomasarisefromtherightorleftventricularendocardium
withalmostequalincidence.
Thetumorstypicallyformapedunculatedmasswithattachmentstotheatrial
septumintheregionoftheovalfossa.Theypresenteitherwithavilloussurface
(seeFig.52.1)orwithasmoothandlobulatedsurface(seeFig.52.5).The
friablenatureofthevilloussurface(seeFig.52.1)mayeasilyleadtodetachment
andembolizationoftumorfragmentsoradherentthrombus.14Myxomasare
thoughttooriginatefrommultipotentialsubendocardialmesenchymalcells.
Histologically,thetumorsarecomposedofpolygonalmyxomacells,embedded
withinamucoidgroundsubstancerichinglycosaminoglycans(Fig.52.14).The
cellularmake-upwithinthetumorisquitevariable,andtheyoftencontain
hemorrhagicfocusesandcysts.11Thestalkusuallycontainsvesselsoflarge
caliber,whichcanoccasionallybeseenoncoronaryangiograms.Theircontent
ofabnormaldeoxyribonucleicacidsuggestsapotentiallyneoplasticnature.14
FIG.52.14 Histologicsectionofamyxomashowingthepolygonal
myxomacellsembeddedwithamucoidgroundsubstancerichin
glycosaminoglycans.
Onechocardiography,tumorsappearheterogeneouswithbothhyperechoic
andhypoechoicfoci(Fig.52.15).74Demonstrationofastalkattachedtotheoval
fossahelpstodifferentiatemyxomasfromotheratrialmassessuchas
rhabdomyoma,hemangioma,secondarymalignanttumors,andthrombi.
Pedunculatedtumorsmayprotrudeacrossvalves,typicallyatrioventricular.In
olderchildren,transesophagealechocardiographymaybehelpfulinvisualizing
atrialtumors.
FIG.52.15 (A)Leftatrialmyxomainapatientwithafamilialmyxoma.(B)
Rightatrialmyxomaprolapsingthroughthetricuspidvalveintotheright
ventricle.Notetheheterogeneouscharacterofboththelesionsand
attachmenttotheovalfossa.
Thetriadofsystemic,embolic,andcardiacmanifestations,aspreviously
described,maydominatetheclinicalprofile,althoughmostexperienceinthis
respectisbasedonadultsratherthanchildren.Insomeseries,signsand
symptomsofmitralvalvardiseasedominatetheclinicalpresentation.Inadult
series,aminorityofpatientsareasymptomatic,withtumorsdetectedasan
incidentalfinding.Cyanosis,systolicmurmur,andcongestiveheartfailurewere
themostcommonpresentingfeaturesininfants.1
Eventhoughmyxomasareconsideredbenign,theirconsequences,suchas
embolizationorobstructiontoflow,canpotentiallybelethal.14,108–110Their
possiblerecurrence,localinvasion,orextensionisalsosuggestiveofa
malignantcharacter.107Theriskofrecurrenceislessthan1in20forthe
sporadicmyxomasbut1in5forthefamilialcases.11,107Removalofthetumoris
thepreferredtherapeuticoption.Thestalkshouldalsoberemovedcompletelyto
reducetheriskofrecurrence.Follow-upevaluationforrecurrenceiswarranted.
Teratomas
Teratomasarerelativelyrareamongallpediatrictumors.Theytendtooccurin
youngerpatientsandarethesecondorthirdmostfrequenttumorinfetaland
neonatalseries.1,5,10Mostareextracardiacandintrapericardial.Theytendtobe
locatedatthebaseoftheheartandattachedtotherootofthearterialpedicle.
Intracardiacteratomasareexceptionallyrare.
Ongrosspathology,teratomasarecomposedofmultilocularcystsseparated
bysolidareas.Microscopically,teratomascontain,bydefinition,elements
derivedfromallthreegermlayersofthebody.Onechocardiography,teratomas
