240

Myofibroblastic sarcoma of the mandible: a case report

Kyung-Ran Park1, Hyo Won Jang1, Ji-Hoon Won1, Hyun-Sil Kim2,3, In-Ho Cha1,3, Hyung Jun Kim1

Departments of 1Oral and Maxillofacial Surgery, 2Oral Pathology, 3Oral Cancer Research Institute, College of Dentistry, Yonsei University, Seoul, Korea

Abstract (J Korean Assoc Oral Maxillofac Surg 2012;38:240-4)

Myofibroblastic sarcoma is a rare tumor that mostly develops in the soft tissues of the head and neck. Within the oral cavity, a tongue lesion is the most common. A myofibroblastic sarcoma tends to recur locally instead of metastasizing. We encountered a myofibroblastic sarcoma of the mandible of a 9-year-old male and performed mass excision and additional marginal alveolectomy. So far, there is neither recurrence nor metastasis. We report this case because of the uncommon location of this tumor type and its surgical approach compared to other forms of sarcomas.

Key words: Myofibroblastic sarcoma, Mandible, Alveolectomy, Uncommon location[paper submitted 2011. 9. 22 / revised 2011. 10. 31 / accepted 2011. 11. 8]

approachcomparedtootherformsofsarcoma.

II. Case Report

InDecember2010,a9-year-oldmalepatientvisitedusdue

tothepainlesssofttissuelesionintherightmandible,which

hefeltstartingamonthearlierwhenhereceivedexcisional

biopsyof the lesion in themandiblebyadentistandgot

diagnosedwithpyogenicgranuloma.Twoweeksafter the

excisionalbiopsy,however,itrecurred;thus,thepatientwas

referredtousafterhereceivedexcisionbiopsyagainandwas

finallydiagnosedwithmyofibroblasticsarcoma.

Intheclinicalexaminationperformedonthedayof the

firstvisit,a3×2cmreddishlesionwithrelativelydistinct

boundaryevaginatedtotherightlingualsideofthemandible

wasidentified;thesurfacewascoveredwithinflammatory

granulationtissues,andithadeasybleedingtendency.An

ulcerwasidentifiedonsomepartof thesurfaceoflesion.

(Fig.1)#46,84, and85adjacent to the lesion showed

mediumlevelofmobilitylaterallyandverticallywhenthe

wire fixationplacedby thedentistwas removed. In the

examinationbytouch,thelesionwasfoundtoextendinto

themandible.Thoughthepatientexperiencedinconvenience,

therewerenospontaneouspainandsignificantparesthesia

in the lower teeth, lower lip,andchin. In thepanoramic

radiographs,onthe#46,85apicalarea,osteolyticlesionwith

relativelydistinctboundarywasobserved,includinginvasion

oflesionontopof#45toothgerms.(Fig.2)Thecomputed

I. Introduction

Intheheadandneck,epithelialmalignanttumorsaccount

forat least80%,andmesodermalmalignant tumorsare

relativelyinfrequent1.Amongmesodermalmalignanttumors,

myofibroblasticsarcomaisaveryrarediseasethatcanoccur

inmostorgans includingskin, limbs,abdominalcavity,

pelviccavity,thoraciccavity,anddiaphragmbutgenerally

afflictstheheadandnecksuchastongue,floorofthemouth,

pharynx,larynx,parapharyngealspace,salivarygland,and

maxillarybones2-6.Withintheoralcavity,tonguelesionisthe

mostcommon.Thoughthetreatmenthasyettobeestablished

clearlyduetothelowincidence,treatmentplansincluding

theextentofsurgicalexcisionaredeterminedconsideringthe

gradeofmalignancy,sizeandlocationoflesion,ageofthe

patient, invasionintoadjacenttissues,andmetastasisafter

biopsyduetovariousgradesofmalignancy7.Weencountered

acaseofmyofibroblasticsarcomaof themandiblewitha

9-year-oldmale,andwearereportingthiscasebecauseof

theuncommonlocationofthistumortypeanditssurgical

Hyung Jun KimDepartment of Oral and Maxillofacial Surgery, College of Dentistry, Yonsei University, 50, Yonsei-ro, Seodaemun-gu, Seoul 120-752, KoreaTEL: +82-2-2228-3132 FAX: +82-2-2227-8022E-mail: kimoms@yuhs.ac

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

CC

CASE REPORThttp://dx.doi.org/10.5125/jkaoms.2012.38.4.240

pISSN 2234-7550·eISSN 2234-5930

Myofibroblastic sarcoma of the mandible: a case report

241

partofthelesion.Nonetheless,thetumorwasdeemedtohave

beenremovedcompletelybecauseadditionalalveolectomy

wasperformedsimultaneouslyonthelowerpartofthelesion.

Thoughthepatientexperiencedtemporaryparesthesiainthe

rightlowerlipandchinafterthesurgery,after3monthsthe

patientwasrestoredandcuredwithoutcomplicationssuchas

inflammationorinfection.

Inthehistologicalexamination, thinandspindle-shaped

myofibroblastswereintersectedwitheachother, invading

thesurroundingtissueslocally.Mostmyofibroblastshada

spindle-shapedcore,butsomehadacircleorapleomorphic

coreandshowedpartialhyperchromatism.Thoughsome

pleomorphic cells showedhigh-gradedysplasia,most

myofibroblastsexhibitedlow-gradedysplasiawithouttissue

necrosis.Bloodcirculationinthesurroundingareawasmore

tomography(CT)andmagneticresonanceimaging(MRI)

revealeda lesionwithrelativelydistinctboundary in the

mandibledestroyingthelingualcorticalboneandextending

totheinsideofthemandiblewithoutinvadingadjacentareas

suchasfloorof themouth,sublingualspace,andtongue.

Therewasnolymphnodemetastasis.(Fig.3)

OnDecember31,2010,thepatientunderwentmassexcision

includingextractionof#84,85,44,45,46,and47and

alveolectomyonthelowerpartofthelesionundergeneral

anesthesia.(Fig.4)Theresectedsoftmassmeasured3×2.5cm

andwaseasilydividedfromthesurroundingtissues;inthe

finalbiopsy,however,tumorcellsweredetectedonthelower

Fig. 1. Intraoral view of soft tissue mass on the lingual side of the mandible showing granulomatous tissue overgrowth.Kyung-Ran Park et al: Myofibroblastic sarcoma of the mandible: a case report. J Korean Assoc Oral Maxillofac Surg 2012

Fig. 2. Initial panoramic view showing radiolucent lesion on #85, 46 apical area with loss of crypt wall of #45.Kyung-Ran Park et al: Myofibroblastic sarcoma of the mandible: a case report. J Korean Assoc Oral Maxillofac Surg 2012

Fig. 3. Radiographic findings of myofibroblastic sarcoma. A. Computed tomography showing osteolytic lesion in the right mandible with cortical destruction on the lingual side. B, C. Magnetic resonance imaging showing 2.5 cm enhancing mass arising from the right mandible with extra-mandibular extension; no gross invasion in the floor of the mouth, tongue, and right sublingual space, with no pathological lymph nodes.Kyung-Ran Park et al: Myofibroblastic sarcoma of the mandible: a case report. J Korean Assoc Oral Maxillofac Surg 2012

J Korean Assoc Oral Maxillofac Surg 2012;38:240-4

242

Oncology,Pedodontics,andOralandMaxillofacialSurgery.

III. Discussion

Myofibroblastisacellintheintermediatestageoffibro-

blast’smyogenesisprocess.Itislocatedinthesofttissues

ofmostorgans6.Duringthetreatmentofwoundorreaction

of responsivecells, temporary fibroblastsareobserved,

but theydiebyapoptosiswhenthe treatment is finished.

If there isaproblemin thisprocess, theybecometumor

cells.Thereasonandphenomenological interpretationof

themyofibroblast’sdifferentiationintotumorcellhavenot

beendiscovereddespitethemanyresearchstudies,andthe

thansufficient,andmitotic indexwasrelatively lowat5

mitoticfiguresper10high-powerfields.(Fig.5)Moreover,

myofibroblast testedpositive for immunohistochemical

stainingwithCD34.Consideringthehistological,clinical,

andradiologicalopinions, thepatientwasdiagnosedwith

pT1N0M0, stage I, low-grademyofibroblastic sarcoma

(LGMS)inthemandible.

Thepatientdidnotreceiveadditionaltreatmentsincluding

radiationandanticancertreatments; threemonthsafterthe

surgery, removabledenturewasplaced in theedentulous

area.Eighteenmonthsafter thesurgery, therewasneither

recurrencenordistantmetastasis.(Fig.6)Thepatienthas

beenexaminedregularlybytheDepartmentofPediatrics,

Fig. 4. Resected specimen showing well-encapsulated mass. A. Buccal side view. B. Lower part side view.Kyung-Ran Park et al: Myofibroblastic sarcoma of the mandible: a case report. J Korean Assoc Oral Maxillofac Surg 2012

Fig. 5. Histological findings of myofibroblastic sarcoma. A. Microscopic appearance showing streaming fascicles of spindle-shaped and stellate myofibroblasts exhibiting pleomorphism (H&E staining, ×200). B. Immunohistochemical staining with CD34 (×100).Kyung-Ran Park et al: Myofibroblastic sarcoma of the mandible: a case report. J Korean Assoc Oral Maxillofac Surg 2012

Myofibroblastic sarcoma of the mandible: a case report

243

powerfields),andpartialtissuenecrosis12.Ifthediagnosis

ishighgradeaftersurgicalexcision,radiationtreatmentis

generallyrecommended,andanticancer treatmentmaybe

usedincombination incaseofhighpossibilityofdistant

metastasis11.Fisherreported that,outof39LGMScases,

13patients (33%)experiencedpartial recurrenceand3

patients(8%)haddistantmetastasis,andthat,outof22cases

ofhigh-grademyofibroblasticsarcoma,7patients (32%)

experiencedpartial recurrenceand15patients(68%)had

distantmetastasis10.AccordingtoMentzeletal.7,outof18

LGMScases,2patientsexperiencedrecurrence,1patienthad

metastasis,14patientsreceivedsurgicalexcision,and4other

patientsreceivedsurgicalexcisionandadditionaltreatments

suchasradiationandanticancertreatments.

Giventhevarietyofexistingtreatmentsandclinicalresults

ofmyofibroblasticsarcoma,histopathologicalevaluation

andclinical/radiographicdeterminationsareveryimportant

factorsofprognosis.Inparticular,forchildrenpatientssuch

asthepatientinthiscase,decidingthepropersurgicalmargin

iscriticalwhileminimizingproblemsinthemandibularbone.

Inthiscase,wewereabletoobtainasuccessfultreatment

resultbyperformingonlyalveolectomycoveringthelesion

whileminimizingproblemsinthegrowthanddevelopment

ofmandible,consideringthefactsthatthelesionhaddistinct

boundaries, therewasno invasion into the surrounding

tissuesexcept the lingual sideof themandibleand#45

permanenttoothgerms,thepatientwasyoungandhehadlow

pathologicalgrade,andthelesiontendedtoshowmorelocal

recurrencethanmetastasis.Nonetheless,themostimportant

thingistosecureacleansurgicalmargin,andthereisaneed

tocheckforrecurrencethroughlong-termobservation.

treatmentmethodformyofibroblasticsarcomahasyet to

beestablished7.This isbecausetherearenotenoughcase

reports,myofibroblasthasvariousandcomplexhistological

differentiationsandgradesofmalignancy,anditsprognosis

canchangeaccording to the locationandsizeof lesion8.

Inexistingresearch,high-grademyofibroblasticsarcoma

isaggressive,showingmoredistantmetastasis than local

recurrence.LGMS,however,showsmorelocalrecurrence

thandistantmetastasisandtendstoinvadeintosofttissues8-10.

LGMSoccurs2.5 timesmorefrequently inmales than

females,generallyafflictingsofttissue,fascia,andsubcutan-

eoustissuessuchasheadandneck,limbs,pelvis,lung,chest,

abdomen,genitals,diaphragm,thyroid,andskin.Withinthe

headandneck,tonguelesionisthemostcommonfollowed

bysalivarygland,floorofthemouth,parapharyngealspace,

andoccipitalarea2,3,5-7,9.Mandibularlesionisanextremely

rarelesionevenforLGMS.Generallyoccurringinthetongue,

itisfeltbythepatientafterthesizeofthelesionincreases

withoutclinicalsymptomorpain,showingdistinctboundaries

inradiologicalimagesandexhibitingosteoclasiaandinvasion

onsomeboundaries.Thiscasehassimilaraspects4.

Forgeneralsarcoma,extensive2-5cmexcisionisperfor-

med,buttherangeofsurgicalexcisionforLGMSisdeter-

minedconsidering theclinicaldecisionsandhistological

opinionsoftheoperator11.Therefore,therangeofexcision

maybedeterminedaccording to theageof thepatient,

sizeandlocationoflesion,destructionofadjacenttissues,

metastasis,andhistologicalgradeofmalignancy.Generally,

thediagnosis ishighgradewhencombiningsize larger

than10cm,deeplocation,highhistologicalgradeofmalig-

nancy(highmitoticindex>10mitoticfiguresper10high-

Fig. 6. Post-operative panoramic X-ray (A) and clinical photo (B) after 18 months.Kyung-Ran Park et al: Myofibroblastic sarcoma of the mandible: a case report. J Korean Assoc Oral Maxillofac Surg 2012

J Korean Assoc Oral Maxillofac Surg 2012;38:240-4

244

7. MentzelT,DryS,KatenkampD,FletcherCD.Low-grademyofibroblasticsarcoma:analysisof18casesinthespectrumofmyofibroblastictumors.AmJSurgPathol1998;22:1228-38.

8. FisherC.Myofibrosarcoma.VirchowsArch2004;445:215-23.9. ArtopoulouII,LemonJC,ClaymanGL,ChambersMS.Stent

fabrication forgraft immobilization followingwide surgicalexcisionofmyofibroblastic sarcomaof thebuccalmucosa:aclinicalreport.JProsthetDent2006;95:280-5.

10. FisherC.Myofibroblasticmalignancies.AdvAnatPathol2004;11:190-201.

11. KawaguchiN,AhmedAR,MatsumotoS,ManabeJ,MatsushitaY.Theconceptofcurativemargininsurgeryforboneandsofttissuesarcoma.ClinOrthopRelatRes2004;(419):165-72.

12. KhouryJD,CoffinCM,SpuntSL,AndersonJR,MeyerWH,ParhamDM.Gradingof nonrhabdomyosarcoma soft tissuesarcomainchildrenandadolescents:acomparisonofparametersusedfortheFédérationNationaledesCentersdeLutteContreleCancerandPediatricOncologyGroupSystems.Cancer2010;116:2266-74.

References

1. Takácsi-NagyZ,MuraközyG,PogányP,Fodor J,OroszZ.Myofibroblasticsarcomaofthebaseoftongue.Casereportandreviewoftheliterature.StrahlentherOnkol2009;185:198-201.

2. BiscegliaM,MagroG.Low-grademyofibroblasticsarcomaofthesalivarygland.AmJSurgPathol1999;23:1435-6.

3. JayA,PiperK,FarthingPM,CarterJ,DiwakarA.Low-grademyofibroblasticsarcomaofthetongue.OralSurgOralMedOralPatholOralRadiolEndod2007;104:e52-8.

4. NiedzielskaI,JanicT,MrowiecB.Low-grademyofibroblasticsarcomaofthemandible:acasereport.JMedCaseRep2009;3:8458.

5. SanMiguelP,FernándezG,Ortiz-ReyJA,LarrauriP.Low-grademyofibroblasticsarcomaofthedistalphalanx.JHandSurgAm2004;29:1160-3.

6. TakahamaAJr,NascimentoAG,BrumMC,VargasPA,LopesMA.Low-grademyofibroblasticsarcomaoftheparapharyngealspace.IntJOralMaxillofacSurg2006;35:965-8.