Incidental appendiceal mucinous neoplasm mimicking a left adnexal mass: A case report

CASE

REPORT

–

OPEN

ACCESS

InternationalJournalofSurgeryCaseReports74(2020)132–135

ContentslistsavailableatScienceDirect

International

Journal

of

Surgery

Case

Reports

jo u r n al ho me p a g e :w w w . c a s e r e p o r t s . c o m

Incidental

appendiceal

mucinous

neoplasm

mimicking

a

left

adnexal

mass:

A

case

report

Ammar

Aleter

_,

_Walid

_El

_Ansari

d_{SchoolofHealthandEducation,UniversityofSk¨ovde,Sk¨ovde,Sweden}

a

r

t

i

c

l

e

i

n

f

o

Articlehistory: Received1July2020

Receivedinrevisedform30July2020 Accepted30July2020

Availableonline12August2020

Keywords:

Appendicealmucinousneoplasm Appendix

Mucocele

Mimickingovariantumor Misdiagnose

Casereport

Pelvicultrasonography

a

b

s

t

r

a

c

t

INTRODUCTION:Appendicealmucinousneoplasmisararetypeofappendicealtumorswhichcanpresent

inavarietyofsymptomsandisdifficulttodiagnose.Preoperativediagnosisdependsmainlyondiagnostic

imagingsuchasultrasonographyandcomputerizedtomography(CT)scan.Thisuncommoncasereport

discussesanappendicealmucinousneoplasmmimickingaleftadnexalmassonpresentation,physical

examinationanddiagnosticimagingfindings.

PRESENTATIONOFCASE:Thisisa61-year-oldfemalefoundtohavealargeleftadnexalmassduringfollow

upultrasonography.Thepatientrefusedfurtherimaging,andduringlaparotomy,shewasfoundtohave

anappendicularmucocelewithnormalleftandrightovaries.

DISCUSSION:Appendectomywasdoneandthefinalpathologycameasappendicealmucinousneoplasm.

Herpost-operativecourseand3yearsfollowupwereuneventful.

CONCLUSIONS:Theequivocalsignsandsymptomsalongwiththeanatomicalpositionofappendiceal

mucocelemakesitdifficulttodiagnoseandcanmimicothertypesoftumors.Therefore,itshouldbe

consideredinthedeferentialdiagnosisoflowerabdominalandpelvicmasses.

©2020TheAuthor(s).PublishedbyElsevierLtdonbehalfofIJSPublishingGroupLtd.Thisisanopen

accessarticleundertheCCBY-NC-NDlicense(http://creativecommons.org/licenses/by-nc-nd/4.0/).

1. Introduction

Appendicealmucoceledescribestheprogressivedilatationof thevermiformappendixduetoabnormalmucusaccumulationin thelumen[1].Mucusisretainedasaresultoflumenobstruction orhyperproductiondue tobenign(fecaliths,postinflammatory fibrosis,hyperplasticpolyps,serratedadenomas)ormalignant(low orhigh-gradeappendicealmucinousneoplasm,carcinoidtumors, mucinousadenocarcinomas)pathologies[2].Appendiceal muco-celesformedduetoappendicealmucinousneoplasms(AMNs)are exceptionallyrare,withanincidenceof0.12casesper1million individualsperyear[3,4].

AMNsareoccasionallyfoundincidentally,duringfollowupor atthetimeofsurgeryforothercauses,andfrequentlydiagnosed inthelatestages[5].ThesymptomsofAMNvarysignificantly,and itisasymptomaticin25%ofcases[6].Hence,awiderangeof dif-ferentialdiagnosesshouldbeconsidered,toincludeappendicitis, mesentericorduplicationcyst,oradnexalmass[7].

∗ Correspondingauthorat:DepartmentofGeneralSurgery,HamadGeneral Hos-pital,Doha,Qatar.

E-mailaddress:[email protected](W.ElAnsari).

Inthecurrentcasereport,wepresentanincidentalappendiceal mucinousneoplasmmimickingaleftadnexalmass.Weusethe AmericanJointCommitteeonCancer(AJCC)8thedition[8]forthe classification,prognosisandtreatmentofAMNs,andthecaseis reportedinlinewiththeupdatedconsensus-basedsurgicalcase report(SCARE)guidelines[9].

2. Casepresentation

A61yearoldJordanianfemalewasreferredtotheobstetricsand gynecologyclinicatourinstitutionfromhealthcenterdueto sus-pectedlargeleftovarianmassdiscoveredbypelvicultrasound(US). Thepatientwaspostmenopausal(gravida7,para6,1abortion).Her lastchildbirthwas25yearsbackandpasthistoryrevealedthatshe underwenthysteroscopyandpolypectomyofanendometrialpolyp 3yearsago.Thenewlydiscoveredmasswasfoundduringher reg-ularfollowup.Uponthisincidentalfinding,thepatientwasnot complainingofanygynecologicalsymptoms.Shewasmenopausal since20years,withnocomplaintsofabdominalpainormass, vagi-nalbleedingordischarge,orweightorappetitelossduringthepast months.Therewerenoothergastrointestinalorurologic symp-toms,andtherestofhersystemicexaminationwasunremarkable. Herfamilyhistorywasnegativeforgynecologicalor gastroenterol-ogycancers,but thepatienthad comorbiditiesincludingtype2

https://doi.org/10.1016/j.ijscr.2020.07.081

2210-2612/©2020TheAuthor(s).PublishedbyElsevierLtdonbehalfofIJSPublishingGroupLtd.ThisisanopenaccessarticleundertheCCBY-NC-NDlicense(http://

CASE

REPORT

–

OPEN

ACCESS

A.Aleter,W.ElAnsari/InternationalJournalofSurgeryCaseReports74(2020)132–135 133

Fig.1. Pelvicultrasoundshowinglargeleftadnexalmass:rightovarycouldnotbe seenattimeofscanduetooverlyingbowelgas.

Fig.2.Pelvicultrasoundshowinglargeleftadnexalmass(10.0×4.2cm)with cal-cifications.

diabetesmellitus,hypertensionandhyperlipidemiawhichwere controlledbyoralmedications.

Examinationofthepatientrevealedthatshewasvitally sta-blewithunremarkableabdominalorgynecologicalfindings,and nomasscouldbepalpatedinthelowerabdomen.Investigations showedthatherlaboratorytestswereunremarkableexceptfor irondeficiencyanemiaand mildlyelevatedcancerantigen19-9 (CA19-9)(40U/mL).Othertumormarkersforovarianandother solidintraperitonealorganswerewithinthenormalrange:cancer antigen125(CA125),cancerantigen15-3(CA15-3)and alpha-fetoprotein(AFP)were9U/mL,13U/mLand2Ng/mLrespectively. HerpelvicUS(Figs.1and2)showedlargeleftadnexalovalshaped heterogeneoussolidmasslesion(10.4×4cm),containingareasof calcification,andtheleftovarycouldnotbeseen.Boththeright ovary(2.9×2cm)andtheuteruswereunremarkable.Nofreefluid wasfoundinthepelvis.ThepatientwasreferredforMRIabdomen andpelvis,butsherefusedtoproceedwithanyfurtherimaging. Theconditionwasdiscussedthoroughlywiththepatientanddue toahighsuspicionofovarianmalignancy,thedecisionwasmade toproceedwithsurgery.Wedidnotstartwithlaparoscopydue tolargetumorsize(10.4×4cm),asexploringthepelvicregion, resectingthetumoranddeliveringitwouldhavebeenvery dif-ficultandcouldexposethepatienttofurthercomplications.The patientwaspostedforexploratorylaparotomywithorwithout totalabdominalhysterectomywithsalpingo-oophorectomy.

Duringlowermidlinelaparotomybyanexperiencedsurgeon andafterfullinspectionofthepelvicorgansincludingrightandleft adnexaalongwiththeuterusandsigmoidcolon,thepatientwas unexpectedlyfoundtohavealargeappendicealmassatthe ter-minalportionofherappendixapproximately15cm(long)×5cm (wide).Theappendixwasintactwithnospillageorperforation, andnoperitonealnoduleswerefound(Fig.3).Theuterusandboth ovarieswerenormal.Appendectomywithexcisionalbiopsyofthe

Fig.3.Appendicularmucocelepostresection:appendixwasremovedintact with-outspillage.Arrowpointstosurgicalknotneartheproximalresectionmarginwhich wasfoundtobefreeofmalignancy.

Fig.4. Villousandflatproliferationofmucinousepithelialcellsliningthe appen-dicealmucosainLAMN,HX&E,x4.

Fig.5.Flatproliferationofmucinousepithelialcellswithlowgradenuclearatypia inLAMN,HX&E,x20.

omentumthatwasattachedtotheappendixwashenceperformed. Thepost-operativeperiodwasunremarkable,withnocomplaints orcomplications,thepatientwasstablevitallyandstarteddieton day1.Shewasfollowedforthenext2daysthendischarged.

Herhistopathologyresultsindicatedadiagnosisoflowgrade appendicealmucinousneoplasm(LAMN,17_×3cm).Figs.4–6show villousandflatproliferationofmucinousepithelialcellsliningthe appendicealmucosawithlowgradenuclearatypia.Theacellular

CASE

REPORT

–

OPEN

ACCESS

Fig.6. AcellularmucindissectthemuscularispropriaoftheappendixinLAMN, HX&E,x10.

mucinouscellshadinvadedintothemuscularispropria,the proxi-malandmesentericmarginswereuninvolvedbytumor,andthere werenoidentifiabletumordeposits,lymphovascularorperineural invasion.Nolymphnodeswherefoundinthesubmittedspecimen andthepathologicalclassificationwaspT2,pNx[10].Staging com-puterizedtomography(CT)scanofthechestandabdomeninorder todetectanydistantmetastasiswerenegative.Thepatientwas referredand discussedatourgastro-intestinalmultidisciplinary (MDT)meeting,andtheplanwastofollowherupintheGeneral surgeryoutpatientclinicwithnoneedforfurtherinterventionor completionsurgery.Thepatientwasfollowedforthenext3years withnosignsofrecurrence.Shewassatisfiedwiththeoutcome. 3. Discussion

AMNis a very raredisease withheterogeneousclinical fea-tures[11]. Tothebestofourknowledge,thecurrentcasecould bethesecondcasereporteddescribinganAMNmimickingaleft ovarian tumor,the first beingfrom United States [12], despite thatmanycasereportsdescribedAMNmimickingarightovarian tumor[13,14]. Accurate preoperative diagnosis of AMNis usu-allydifficultdue to itsdiverseclinical features, lackof specific tumorbiomarkers, and susceptibilityof appendiceal neoplasms toinvolve/ metastasizetotheovarieshencemimicking ovarian tumors[11,15].

Intermsofdemographics,thecurrentpatientwasafemaleaged 61years, inagreementwithotherreports suggestingthat AMN tendstohaveaslightfemaleprevalenceandistypicallyfoundin patientsintheir5thand6thdecades;although,itmayoccuratany age[6,16].

As for presentation, the possible symptoms of appendiceal mucocelerangefromlowerabdominalorpelvicpain,fever, nau-sea,andvomitingtoasymptomaticpresentation[16,17].Ourcase representsaclassicexampleofthelackofsymptomsanddifficulty indiagnosisasthepatientwasactuallyasymptomaticandthemass wasfoundincidentallyduringroutineUSfollowup.

Intermsofimaging,diagnosisofappendicealmucoceleoften dependsondiagnosticimaging, anda main featurethat distin-guishesappendicealmucocelefromuncomplicatedappendicitisby USisthelackofappendicealwallthickeningof>6mm[18,19].We wereunabletoconfirmthepresenceorabsenceofappendiceal wallthickeningastheappendixcouldnotbeseparatelyidentified inrightiliacfossaduetoobscuringbowelgasandlargepelvicmass. SeveralUSappearancesspecificforappendicealmucocelemight beencounterede.g.abottle-likeshapedsolidappendicularmass slidingovertheuterusandovaries[19,20]orthehighlyspecific “onionskinsign”(concentricechogeniclayerswithseptaandfine

echoes)[21,22]canhelptodistinguishappendicealmucocelefrom anovariancyst.Unfortunately,suchdiagnosticappearanceswere notevidentintheUSweundertook.Otherssuggestedthatthe pres-enceoftheonionskinsignwithinacysticmassintherightlower abdominalquadrant,withanormalrightovary,couldbespecific forthediagnosisofappendicealmucocele[22].

Colonoscopy,MRI,andcomputedtomography(CT)areall valu-ableinvestigationsthatcanaidinreachinganaccuratediagnosis [23].Colonoscopicfindingse.g.“volcanosign”(appendicealorifice seeninthecenterofa firmmoundcoveredbynormal mucosa) and a bulbous submucosal lesion of the cecum, establish pre-cisediagnosisand areusefulfor themanagement [24].In MRI, appendicealmucocelelesionsarewellencapsulatedcysticmasses, hyperintenseonT2-weightedsequences,andhypo-orisointense onT1-weightedsequences[25].ThetypicalCTappearanceofan appendicealmucoceleisalargeandwell-encapsulatedcysticmass intheexpectedregionoftheappendix;calcificationsofthecyst wallareveryspecifictoappendicealmucoceleandarevaluable tocharacterizethemucocelefromanabscesscollection[25,26]. AlthoughCTisconsideredthemostinformativeimagingtechnique, thediagnosisismoredifficultintheabsenceofcysticcalcifications andfailuretoidentifytheorganoforigin[27].Unfortunately,the currentpatientrefusedtoprovideconsenttoproceedwithany fur-therimaging (eitherCT abdomenorMRIabdomen)asasecond modalityofdiagnosis.

Althoughalltheimaging techniquesand related signs high-lightedabovecanhelptodifferentiateanappendicealmucocele fromprimaryovariantumors,aprimaryAMNisrarelydiagnosed beforeoperationand histopathologicalexaminationwhen com-paredwithothermorefrequenttypesofappendicealorcolonic tumors[15].Hence,recentviewsadvocateconsideringAMNinthe differentialdiagnosisofanypelvicmassinelderlyfemalepatients, andnottorelymainlyonpreoperativeimagingtools[13–15].

Inourcase, thepre-operativemisdiagnosiswaspossiblydue to:a)thespecific‘onionskin’signwasnotevidentonUS;and,b) althoughcalcificationswithinthemassandthewallwerepresent, therightovarywasnotrecognizedduetoobscuringbowelgas,and themasswasmimickingaleftadnexalmass(Fig.2).Findingofa largeleftadnexalmassoccupyingthepelvicregionusuallyprompts additionaldiagnosticimagingtofurtheroutlinetheanatomybefore intervention,butthepatientrefusedfurtherMRIimaging.Others havereportedamisdiagnosedovarianmassduringpreoperative evaluationwhichturnedouttobeappendicealmucoceleduring surgicalexploration,andattributesuchmisdiagnosistothe mim-ickingsymptoms, nearbysurgicalanatomy and invasion ofthe neoplasmtothesurroundingovariesanduterus[13].

Asfortheprocedure,upondirectvisualizationofthelesionat thetimeofsurgery,thesurgeonrecognizedthispathologicalentity andperformedasimpleappendicectomythatwasneeded,andthe patientwasreferred forlongtermfollow-upafterdiscussionat ourgastrointestinalMDTmeeting.Thepatientwasrecentlyseen attheclinicafter3yearsoffollowupand wasrecurrence-free, usingtumormarkers(noelevation),colonoscopy,andimaging.

4. Conclusions

Thesymptomsofappendicealmucocelevarysignificantlyand arerelativelysimilartoovariantumors.Thesesimilarsignsand symptoms,alongwiththeanatomicalpositionoftheappendiceal mucocele,rendersitdifficulttodiagnoseappendicealmucoceleas itcanmimicothertypesoftumors,particularlyovariantumors. Althoughmultiplediagnosticimagingtechniquescanaidin reach-inganaccuratediagnosis,aprimaryAMNisrarelydiagnosedbefore operationandhistopathologicalexamination.Hence,high

suspi-CASE

REPORT

–

OPEN

ACCESS

A.Aleter,W.ElAnsari/InternationalJournalofSurgeryCaseReports74(2020)132–135 135 cionisrequired,andrecentviewsadvocateconsideringAMNinthe

differentialdiagnosisforanypelvicmassinelderlyfemalepatients.

DeclarationofCompetingInterest

Theauthorsreportnodeclarationsofinterest.

Sourcesoffunding

Nothingtodeclare.

Ethicalapproval

ApprovedbytheMedicalResearchCenter(IRB),HamadMedical Corporation,referencenumber(MRC-04-20-133).

Consent

Writteninformedconsentwasobtainedfromthepatientfor publicationofthiscasereportandaccompanyingimages.Acopy ofthewrittenconsentisavailableforreviewbytheEditor-in-Chief ofthisjournalonrequest.

Author’scontribution

AmmarAleter:datacollection,interpretation,writingthepaper, editingthepaper.WalidElAnsari:studyconcept,data interpreta-tion,writingthepaper,editingthepaper.Allauthorsreviewedand agreedonthefinalversionofthepaper.

Registrationofresearchstudies

NotfirstinMan.

Guarantor

WalidElAnsari:[email protected]. Provenanceandpeerreview

Notcommissioned,externallypeer-reviewed. References

[1]A.Mastoraki,G.Sakorafas,P.Vassiliu,etal.,Mucoceleoftheappendix:

dilemmasindifferentialdiagnosisandtherapeuticmanagement,IndianJ.

Surg.Oncol.7(1)(2016)86–90.

[2]N.J.Carr,T.D.Cecil,F.Mohamed,etal.,Aconsensusforclassificationand

pathologicreportingofpseudomyxomaperitoneiandassociatedappendiceal

neoplasia:theresultsoftheperitonealsurfaceoncologygroupinternational

(PSOGI)modifiedDelphiprocess,Am.J.Surg.Pathol.40(2016)14–26.

[3]W.L.Shaib,M.Goodman,Z.Chen,S.Kim,etal.,Incidenceandsurvivalof

appendicealmucinousneoplasms:aSEERanalysis,Am.J.Clin.Oncol.40(6)

(2017)569–573.

[4]C.Bartlett,M.Manoharan,A.Jackson,Mucoceleoftheappendix—adiagnostic

dilemma:acasereport,J.Med.CaseRep.1(2007)183.

[5]H.H.Gonzalez,K.Herard,M.C.Mijares,Ararecaseoflow-gradeappendiceal

mucinousneoplasm:acasereport,Cureus11(1)(2019)e3980.

[6]E.Kalu,C.Croucher,Appendicealmucocele:araredifferentialdiagnosisofa

cysticrightadnexalmass,Arch.Gynecol.Obstet.271(1)(2005)86–88.

[7]A.H.Omari,M.R.Khammash,G.R.Qasaimeh,A.K.Shammari,M.K.Yaseen,S.K.

Hammori,Acuteappendicitisintheelderly:riskfactorsforperforation,

WorldJ.Emerg.Surg.9(1)(2014)6.

[8]M.J.Overman,E.A.Asare,C.C.Compton,etal.,in:M.B.Amin,S.B.Edge,F.L.

Greene,etal.(Eds.),AJCCCancerStagingManual,8thedition,Springer,

Chicago,IL,2017.

[9]R.A.Agha,M.R.Borrelli,R.Farwana,K.Koshy,A.Fowler,D.P.Orgill,Forthe

SCAREGroup,TheSCARE2018statement:updatingconsensusSurgicalCAse

REport(SCARE)guidelines,Int.J.Surg.60(2018)132–136.

[10]S.E.Edge,D.R.Byrd,C.C.Compton,etal.,AJCCCancerStagingManual,7th

edition,Springer,NewYork,NY,USA,2009.

[11]A.M.Mehta,M.B.Bignell,S.Alves,etal.,Riskofovarianinvolvementin

advancedcolorectalorappendicealtumorsinvolvingtheperitoneum,Dis.

ColonRectum60(2017),691e6.

[12]A.Hajiran,K.Baker,P.Jain,M.Hashmi,Caseofanappendicealmucinous

adenocarcinomapresentingasaleftadnexalmass,Int.J.Surg.CaseRep.5(3)

(2014)172–174.

[13]O.Balci,S.Ozdemir,A.S.Mahmoud,Appendicealmucocelemimickingacystic

rightadnexalmass,Taiwan.J.Obstet.Gynecol.48(4)(2009)412–414.

[14]P.Panagopoulos,T.Tsokaki,E.Misiakos,V.Domi,etal.,Low-grade

appendicealmucinousneoplasmpresentingasanadnexalmass,CaseRep.

Obstet.Gynecol.2017(2017),7165321.

[15]W.Zhang,C.Tan,M.Xu,X.Wu,Appendicealmucinousneoplasmmimics

ovariantumors:challengesforpreoperativeandintraoperativediagnosisand

clinicalimplication,Eur.J.Surg.Oncol.45(11)(2019)2120–2125.

[16]J.Ruiz-Tovar,D.G.Teruel,V.M.Castineiras,A.S.Dehesa,P.L.Quindos,E.M.

Molina,Mucoceleoftheappendix,WorldJ.Surg.31(3)(2007)542–548.

[17]W.L.Shaib,R.Assi,A.Shamseddine,etal.,Appendicealmucinousneoplasms:

diagnosisandmanagement,Oncologist22(9)(2017)1107–1116.

[18]W.C.Lien,S.P.Huang,C.L.Chi,etal.,Appendicealouterdiameterasan

indicatorfordifferentiatingappendicealmucocelefromappendicitis,Am.J.

Emerg.Med.24(7)(2006)801–805.

[19]S.Degani,I.Shapiro,Z.Leibovitz,G.Ohel,Sonographicappearanceof

appendicealmucocele,UltrasoundObstet.Gynecol.19(1)(2002)99–101.

[20]C.Malave,G.Wynn,M.S.Nussbaum,A.M.Kaunitz,Incidentaldiagnosisof

appendicealmucocelewithvaginalultrasonographyandcomputed

tomography,Obstet.Gynecol.117(2)(2011)479–481.

[21]R.K.Demirci,M.Habibi,B.R.Karakas¸,H.Bulus¸,etal.,Appendixmucocele

mimickingacomplexovariancyst,Ulus.CerrahiDerg.31(1)(2015)58–60.

[22]B.Caspi,E.Cassif,R.Auslender,A.Herman,Z.Hagay,Z.Appelman,Theonion

skinsign:aspecificsonographicmarkerofappendicealmucocele,J.

UltrasoundMed.23(1)(2004)117–123.

[23]Y.O.Tanaka,Y.Takazawa,M.Matsuura,K.Omatsu,N.Takeshima,K.

Matsueda,MRimagingofsecondarymassiveovarianedemacausedby

ovarianmetastasisfromAppendicealAdenocarcinoma,Magn.Reson.Med.

Sci.18(2)(2019)111–112.

[24]M.Shiihara,T.Ohki,M.Yamamoto,Preoperativediagnosisandsurgical

approachofappendicealmucinouscystadenoma:usefulnessofvolcanosign,

CaseRep.Gastroenterol.11(3)(2017)539–544.

[25]M.Puvaneswary,A.Proietto,Mucoceleoftheappendixwithmagnetic

resonanceimagingfindings,Australas.Radiol.50(1)(2006)71–74.

[26]S.A.Laalim,I.Toughai,B.Benjelloun,K.H.Majdoub,K.Mazaz,Appendiceal

intussusceptiontothececumcausedbymucoceleoftheappendix:

laparoscopicapproach,Int.J.Surg.CaseRep.3(9)(2012)445–447.

[27]G.L.Bennett,T.P.Tanpitukpongse,M.Macari,K.C.Cho,J.S.Babb,CTdiagnosis

ofmucoceleoftheappendixinpatientswithacuteappendicitis,Am.J.

Roentgenol.192(3)(2009)103–110.

OpenAccess

ThisarticleispublishedOpenAccessatsciencedirect.com.ItisdistributedundertheIJSCRSupplementaltermsandconditions,which permitsunrestrictednoncommercialuse,distribution,andreproductioninanymedium,providedtheoriginalauthorsandsourceare credited.