Case
Report
TMJ
Disorders
Intra-articular
loose
osteochondroma
of
the
temporomandibular
joint
P.Graziano,A.Spinzia,V.Abbate,A.Romano:Intra-articularlooseosteochondroma ofthetemporomandibularjoint.Int.J.OralMaxillofac.Surg.2012;41:1505–1508. #2012InternationalAssociationofOralandMaxillofacialSurgeons.Publishedby ElsevierLtd.Allrightsreserved.
P. Graziano,A. Spinzia,V. Abbate, A. Romano
DepartmentofOralandMaxillofacialSurgery, SchoolofMedicine,UniversityofNaples, FedericoII,Naples,Italy
Abstract. Osteochondromaorosteocartilaginousexostosisisoneofthemostcommon benignbonetumours.Itusuallydevelopsinthemetaphysesoflongflatbones,but rarelyoccursintheoralandmaxillofacialarea,whereitisgenerallyassociatedwith thecoronoidprocessorthecondyle.Looseosteochondromasinsidethejointare generallyararepathologyusuallydescribedinlargejoints.Theauthorspresenta caseofanintra-articularlooseosteochondromaofthetemporomandibularjoint (TMJ),whichrepresentsthefirstcaseofsuchapathologicalentityintheliterature. Theauthorssuggestthatitshouldbeconsideredinanydifferentialdiagnosisof loosebodiesdescribedintheTMJ.
Acceptedforpublication11November2011 Availableonline31March2012
Osteochondroma or osteocartilaginous exostosis, one of the most common benignbonetumours,consistsofan exo-phytic bone proliferationwitha hyaline cartilagecapprotrudingfromthesurface oftheaffectedbone.Itusuallydevelopsin the metaphyses of long flat bones, but rarelyoccursintheoralandmaxillofacial area,whereitisgenerallyassociatedwith thecoronoidprocessorthecondyle.3This tumourcanoccursinglyoraspartofan autosomaldominantsyndromeknownas osteochondromatosis.6Different aetiolo-gieshavebeenproposed.Themostrecent theoryis basedonthepresenceofnests of chondrocytes in the periosteum.8 Mechanicalstressmayleadtohyperplasia ofthesecells,becausethelesionisusually locatedinareassuchasthetendon inser-tions.Malignantchangeisrareinsolitary osteochondromas, approximately 2% of
cases, but does occur in approximately 5%ofcasesofmultiplehereditary osteo-chondromatosis. No case of malignant transformation hasbeen reportedin the skull.1Mostcasesofcondylar osteochon-dromamanifestwithfacialasymmetryor malocclusion (ipsilateral posterior open bite,contralateralcrossbite)withlimited temporomandibular joint (TMJ) move-ments. Loose osteochondromas inside the jointareavery rarepathology. Sar-mientoandElkins9havereportedacase thatshowedalargeintra-articular osteo-cartilaginousloosebodyinthekneejoint and termed it a giant intra-articular osteochondroma. Milgram and Dunn5 described a case that presented with an osteochondraltumourandtwocasesthat presented with chondraltumours in the knee joint defined as an intra-articular osteochondroma and an intra-articular
chondroma, respectively. Lim reported a case of extraskeletal osteochondroma ofthebuttock.4Therearenocasesinthe literature of TMJ involvement. The authors present a case of intra-articular looseosteochondromaoftheTMJ,which represents thefirstcaseofsucha patho-logicalentityintheliterature.
Casereport
A 22-year-old woman presented at the authors’department withfacial asymme-try.Shereportedthatithadappearedatthe age of15years and had been gradually increasing. Herpastmedicalhistory was unremarkable.Shedidnothave any his-tory ofTMJ dysfunctionanddenied any recent trauma to the ear or mandible. Physical examination showed facial asymmetry with right lateral deviation
Int.J.OralMaxillofac.Surg.2012;41:1505–1508
doi:10.1016/j.ijom.2011.11.018,availableonlineathttp://www.sciencedirect.com
of the chin (Fig. 1a).The dental occlu-sion wascharacterizedbyclassIII mal-occlusionwitharightlateralmandibular deviation (Fig. 1b–d). The patient had normal mouth opening, without devia-tion,andthemandibularrangeofmotion
was normalinall directions.Therewas nosoundintheTMJandnopainduring the mandibular functionality examina-tion.Therewasnofacialnerveparalysis or paresis. The rest of the head and neck examination wasunremarkable. A
clinical differential diagnosis should include all the pathological conditions thatcanoccurwithmandibulardeviation and malocclusion. The most common should include giant cell tumour, con-dylar hyperplasia, fibro-osseous lesion, vascular malformation, osteoma, chon-droma, and osteochondroma. More rarely reported condylar tumours have included chondroblastoma, chondrosar-coma, osteoblastoma osteoid osteoma, enchondroma, osteosarcoma, and meta-statictumours.
Orthopantomography revealed an oval hyperdensemassadjacenttotheleft con-dyle ofthe TMJ (Fig. 2a). A computed tomography (CT) scan was obtained, which showed a bony dense formation ofabout2cm1.5cmintheleftglenoid fossa.Theformationhadanoval appear-ancewithawell-definedperipheral sclero-sis rim with some patchy areas of low density.Themandibularcondylewas dis-locatedanteriorlywithanewjointreported with the tubercle of the temporal bone (Fig.2b).The radiographicfeatureswere compatiblewithanosteochondromaandit appeared completely detached from the articular bone surfaces. The patient was takentotheoperatingroomandaccesswas gainedtotheleftTMJwithapreauricular approachextendingtothetemporalregion. The incision was made throughthe skin and subcutaneous tissues (including the temporoparietalfascia) asfarasthe tem-poralfascia(superficiallayer).Anincision was made inthe superficial layerof the temporalfasciaanddissectionsweretaken atthelevelofthezygomaticarchasfaras the lateral surface of the capsule of the TMJ.Afterwards,anincision ofthejoint capsulewas performed togainaccess to thelowercompartmentoftheTMJcavity (Fig.3a).A2cm1.5cmmass,adjacent to and behind, the left condyle of the TMJ was found. At surgical exploration themasshadnoconnectionwiththe adja-centbonystructures;thecondyleappeared completelyintact.Themasswascarefully isolatedandremovedfromtheTMJcavity (Fig.3b).Thewoundwassuturedinlayers and a pressure bandage applied, which remainedinplacefor3days.Histological examination showed a nodular mass consistingoflamellarbone,partially bor-dered by a thin rim of cartilage tissue (Fig. 3c). These aspects were consistent withtheresultsofacompletedetachment of osteochondroma. A resolution of the facialasymmetryanddentalmalocclusion was obtained (Fig. 4a). The follow-up examination at 18 months revealed no clinicalorradiologicalsignofrecurrence (Fig.4b).
1506 Grazianoetal.
Fig.1.Patientshowing(a)facialasymmetry;(b,c)dentalIIIclassmalocclusionwith(d)right lateralmandibulardeviation.
Fig.2. (a)Orthopantomogramshowinganovalhyperdensemassadjacenttotheleftcondyleof the TMJ. (b) Sagittal CT scan(bone window) showing a bony dense formation ofabout 2cm1.5cmintheleftglenoidfossa(coronalCT).
Discussion
Osteochondroma or osteocartilaginous exostosis, a cartilage-capped exophytic lesionthatarisesfromthebonecortex,is one of the most common benign bone tumours.Itusuallyoccursintheaxial ske-leton,especiallyinlongbones,suchasthe distalmetaphysisofthefemurorthe prox-imalmetaphysisofthetibia.3Theoraland
maxillofacial region are not commonly involved.Thecoronoidisthemostaffected siteintheskullfollowedbythecondyle.3 The aetiology and pathogenesis of this lesionarenotfullyunderstood.Themost recenttheoryisbasedonthepresenceof nests ofchondrocytes in theperiosteum, mechanical stress possibly leading to hyperplasia ofthese cells.The lesion in theTMJisusuallydiscoveredincidentally
onradiographicexaminationoron palpa-tion ofaprotrudingmass intheaffected area.
Malocclusion in the form ofa lateral open bite on the contralateral side and progressivefacialasymmetryarecommon findings inmostcasesofcondylar osteo-chondroma.Painmayprecedeor accom-panyfacialasymmetryinsomecases.The lesiongrowsslowlyandisalmostpainless. Inthemandibularcondyleitcauses lim-ited movementofthejaw. These condi-tions may also be found in unilateral condylarhyperplasiaandotherdifferential diagnosesincludingosteoma,chondroma, giant cell tumour, myxoma, fibro-osteoma, fibrous dysplasia, fibrosarcoma andchondrosarcoma.10
Inspiteofthecommonclinicalfeatures, a definitive diagnosis should always be basedonclinical,radiological and histo-logical criteria. Conventional panoramic radiographyandCTmayhelptodelineate theanatomyofthelesionandsurrounding structures.Thelesionsusuallypointaway fromthejointspaceandcanhavea ped-unculatedstalkorsessilebase. Osteochon-dromasshouldberemovedbecauseofthis dysfunction andthepossibilityof malig-nant transformation. Several surgical approaches have been suggestedfor the treatment of condylar osteochondroma, including complete resection of the tumourusingcondylectomywithor with-out reconstruction or selected tumour removal without condylectomy.2 If the tumour involves only a limited area of the condylar surface, preservation ofthe remainingpartofthecondyleand reshap-ingshouldbeundertaken.
Inthepresentcase,theauthorsremoved only the intra-articular loose osteochon-droma, which appeared completely detachedfromthearticularbonesurfaces. Thisosteochondromaprobablyoriginated fromahyperplasiaofthechondrocytesin theperiosteum7duetopersistent mechan-icalstress.Theauthorsthinkthatthesame stressmayhaveledtothedetachmentof theosteochondralfragment,althoughthe possibility of extraskeletal osteochon-dromahasbeendescribed,4the pathogen-esisofwhichisunknown.
Thisis thefirst case ofintra-articular loose osteochondroma of the TMJ reported in the literature. The authors suggest that it should be considered in anydifferentialdiagnosisofloosebodies describedintheTMJ.7
Funding None.
Intra-articularlooseosteochondromaoftheTMJ 1507
Fig.3. (a)JointcapsuleincisiontogainaccesstothelowercompartmentoftheTMJ.(b)A 2cm1.5cmtumourmassremovedfromtheTMJ.(c)Histologicalsection(haematoxylin– eosin10)showinganodularmassconsistingoflamellarbone(*)partiallyborderedbyathin rimofcartilagetissue(arrows).
Fig.4. Resolutionof(a)facialasymmetryand(b)dentalmalocclusion.(c)SagittalCT(bone window)showingnoradiologicalsignofrecurrenceat18monthfollowupexamination.
Competinginterests Nonedeclared. Ethicalapproval Notrequired.
Acknowledgments.Theauthorsaregreatly indebted and thankful to Luigi Califano MDDirectorofDivisionofMaxillo-Facial Surgeryofthe‘‘UniversityStudyofNaples FedericoII’’andGiovanniDellAversana OrabonaPhDMedicalConsultantof Divi-sionofMaxillo-FacialSurgeryofthe ‘‘Uni-versity StudyofNaplesFedericoII’’,for theirunstintingeffortsandutterdevotionin thedevelopmentofthisarticle.
References
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4. Lim SC, Kim YS, Kim YS, Moon YR. Extraskeletal osteochondroma of the but-tock.JKoreanMedSci2003;18:127–30. 5. MilgramJW,DunnEJ.Para-articular
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Address:
PasqualeGraziano
ViaPansinin8580131Naples Italy
Tel:+390817462175/3477463028 E-mail:dottgraziano@gmail.it
