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ABSTRACT: Synovial chondromatosis of the temporomandibular joint (TMJ) is a rare lesion character-ized by the presence of loose bodies in the glenoid fossa. Swelling, unilateral pain, occlusal changes,clicking, crepitation, deviation, and limited mandibular function are the most common characteristics,although this combination is not always apparent. Radiopacities of the TMJ should be thoroughly inves-tigated as some signals and symptoms may be not present or combined, taking months or even yearsto confirm a diagnosis. A case report is presented here with a brief literature review, where surgicalremoval was the therapy of choice, calling attention to the absence of symptoms and some signals,which may mislead final diagnosis.

Dr. Denis Pimenta e Souza is a postgraduate student in the oral and maxillo-facial program, School of Dentistry,University of São Paulo, and an oral andmaxillofacial surgery assistant professorin the Section of Oral and MaxillofacialSurgery, Hospital Santa Paula, SãoPaulo, Brazil.

Synovial chondromatosis is an uncommon benignmonoarticular arthropathy characterized by the for-mation of multiple cartilaginous or osteocartilagi-

nous metaplastic nodules in synovial and subsynovialconnective tissue of the joints.1-10 It most frequentlyaffects the large articular joints such as knee, hip, elbow,shoulder, and wrist.5-7,11-13 Although, the involvement ofthe temporomandibular joint (TMJ) is rare, many caseshave been published since 1933, when Georg Axhausenreported the first case.3,10,12-15

Osteocartilaginous loose bodies of TMJ can arise as adirect result of the proliferative disorder of the sinovium(sinovial chondromatosis), or secondary to osteochondralfractures or osteoarthritis9,14,16,17 (secondary sinovialchondrometaplasia). The primary form seems to be moreaggressive and bone erosive and probably originates frommesenchymal remnants that become mataplastic, calcify,and break off into the joint space. The secondary form isassociated with degenerative, inflammatory and nonin-flammatory diseases and is a more passive process.7,8

Swelling, unilateral pain, occlusal changes, clicking,crepitation, deviation, and limited mandibular functionare the most common characteristics, although this com-bination is not always apparent.1,9,10,14,16,18 Since the syn-

Synovial Chondromatosis of the TemporomandibularJoint: An Asymptomatic Case Report and LiteratureReview

Denis Pimenta e Souza, D.D.S.; Caio Cesar de Souza Loureiro, D.D.S.; Paula Felix Falchet, D.D.S.; Luiz Fernando Lobo Leandro, D.D.S., Ph.D.; Ricardo Raitz, D.D.S., Ph.D.

n CASE REPORT

Manuscript receivedAugust 19, 2008; acceptedJanuary 7, 2009

Address for correspondence:Dr. Ricardo RaitzAv. Heitor Peneteado, 1832,101/ACEP: 05438-300Sumarezinho, São Paulo-SPBrazilE-mail: ricardoraitz@ig.com.br

ovial chondromatosis of the TMJ is a rare condition,these features may be easily misdiagnosed as neoplasia orother pathologies.7,12,13

Imaging diagnoses includes conventional x-ray exami-nation, computed tomography (CT), and magnetic reso-nance imaging (MRI). Recently, arthroscopy has beenused as a more conservative means of obtaining a defini-tive diagnosis13,16 and removing loose bodies when theyare small enough for the instrument.6,12,15 Arthrotomy orthe surgical removal of the loose bodies, with or withoutresection of the synovial membrane and disk2,4,12,15 arestill largely used therapies, as they dispense with usingexpensive equipment and allow seeing and biopsyingcritically the pathologic tissues. Here is presented a casereport where the surgical removal was the therapy ofchoice, calling attention to the absence of symptomswhich may mislead final diagnosis.

Case Report

A 28-year-old man was referred to the Section of Oraland Maxillofacial Surgery at the Hospital Santa Paula(São Paulo, Brazil) by his orthodontist who first noticedsome radiopaque particles in the region of the right TMJ,through an orthodontic documentation.

On clinical examination, no evidence of facial asym-metry or malocclusion was noticed. There was no limita-tion of mandibular movement nor mandibular deviationduring mouth opening (Figure 1). Swelling and crepita-tion were noticed while palpating the right TMJ. Thepatient denied any history of trauma to the maxillofacialregion. Intraorally, it was noted the absence of several

teeth and severe periodontitis.Conventional panoramic radiography demonstrated a

radiopaque mass into the glenoid fossa of the right tem-poral bone and around the head of the right condyle,which showed no deformity (Figure 2). A CT scanrevealed the presence of multiple round-shaped, high-density masses, with aspect of loose bodies, located nearthe right temporal eminence occupying the joint spacewhere the disk should be positioned (Figure 3).

These clinical and image findings led us to a diagnos-tic hypothesis of synovial chondromatosis. It was decidedto access the glenoid fossa surgically in order to take abiopsy of the affected tissues or only remove the loosebodies.

After induction of general anesthesia, the TMJ andinfratemporal fossa were approached via modified preau-

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Figure 1No evidence of facial asym-metry, no limitation ofmandibular movement duringmouth opening movement,nor mandibular deviation.

Figure 2Pre-operative panoramic radiography revealed radiopacities in the areaof the right TMJ.

Figure 3Axial computed tomography scan demonstrating multiple high-densitymasses around the right TMJ.

ricular incision (Figure 4). White, irregularly shapedloose bodies escaped from the TMJ upper space after thejoint capsule was opened (Figure 5). The glenoid fossawas explored, and the adherent cartilaginous mass freedfrom its attachments to the fossa walls. All the loosebodies were removed (Figure 6). Since the condyle andthe disk were macroscopically normal, condilectomy andmeniscectomy were not indicated and so closure wasobtained with preservation of the synovium, capsule, andcondyle.

Postoperatively, the patient displayed decreased painand swelling, but some little limitation on mandibularrange of motion was noticed for 15 days. At a two-yearfollow-up, the mandibular range of motion continues tobe normal, and the patient has had no symptoms.Radiographic examination showed no signs of recurrence(Figure 7).

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Figure 4Modified preauricularincision to approachinfratemporal cavity.

Figure 5Loose bodies migrated from the upper compartment after incision ofthe capsule.

Figure 6Irregularly shaped, white, cartilaginous nodules removed from jointcompartment at surgery.

Figure 7Post-operative panoramic radiography at two-years follow-up, show-ing no recurrence of the lesion.

Discussion

This case of Synovial chondromatosis is considereduncommon as large articular joints such as knee, hip,elbow, shoulder, and wrist usually are mostly affectedinstead of the TMJ.1-3,5-7,11-13 For the characteristicsassessed, one could conclude that this is a primary formof the pathology, which is represented as a benign carti-laginous metaplasia of mesenchymal tissue with rem-nants arising in the synovial membrane where fibroblastsbeneath its surface become metaplastic and deposit chon-dromucin. Thus, a cartilaginous focus is stimulated, andonce formed, it grows by active cellular proliferation.7,8

Once the cartilaginous metaplastic and calcified nod-ules4,7,14,15 arise from the synovial membrane, as well asfrom the fibrocartilaginous disk tissue, they extrude to thejoint space as loose bodies, often surrounded by fibrosedconnective tissue where they are nourished by the syn-ovial fluid,3-5,10,13,15 occupying the joint space where thedisk should be positioned, and usually causing pain.Surprisingly, this patient was asymptomatic and thelesion was first noticed through an orthodontic documen-tation. Moreover, only preauricular swelling, and crepita-tion were present in this case. These few characteristicsmay lead this lesion to be misdiagnosed as neoplasia,especially chondrosarcoma12 or other pathologies such asdegenerative joint disease, rheumatoid arthritis, neu-rotrophic arthritis, tuberculosis, and osteochondritis ossi-ficans.6,7 Therefore, imaging examinations such asradiographies, CT scanning, and MRI must be carried outfor a correct diagnosis and therapy.7,12,13,19

Radiographic appearance is variable and may includewidening of the joint space, manifestations of degenera-tive changes of the articular surfaces, and expansion ofthe joint capsule, but evidence of loose bodies is notalways present, being found in only 60% of the cases.11,16

This was the case herein reported, where radiopaque par-ticles could be seen into the glenoid fossa (Figure 2). CTplays an important role in the diagnosis of the TMJ syn-ovial chondromatosis, since it can demonstrate soft tissueswelling, possible change of the articular surface of thetemporal bone, and define size, shape, and locations ofthe loose calcified bodies2,16,19 (Figure 3). However, MRIis mostly used to establish the expansion and thickeningof the joint capsule and morphologic changes in the posi-tion of the disk.16

Immunohistopathological studies have shown that dif-ferent growth factors and hormones may play an impor-tant role in the pathogenesis of synovial chondromatosis.Fujita, et al.3 reported that Transforming Growth Factor β(TGF-β) and Tenascin (TN) were strongly present in thesynovial membrane and in the extracellular matrix of the

synovial intima, respectively. TGF seems to increase dif-ferentiation of mesenchymal cells, production of proteo-glycans, and replication of chondroblasts, while TN isimportant for chondrogenesis in the extracellular matrixand the condensing mesenchyme of developing bones.These findings support the metaplastic theory of synovialchondromatosis in the TMJ since neither TGF nor TN arenormally present in the synovial membrane of normaljoints. Sato, et al.10 reported that different fibroblastgrowth factors (FGF) and their respective receptors(FGFR) may be strongly related to the development ofsynovial chondromatosis. In their study, FGF-2 andFGFR-1 immunoreactivities were observed in chondro-cytes while FGFR-3 and its specific ligand, FGF-9, wereimmunohistochemically observed at the margins of thecartilage nodules. It was concluded that expression ofFGFR-1 in chondrocytes contributes to the growth poten-tial of synovial chondromatosis, and that the FGF-2/FGFR-1 system may play an important role, as well asthe FGF-9/FGFR-3 system, in its pathogenesis.

Recently, arthroscopy of the TMJ, by providing tissuefor a histomorphologic analysis, has been used as a moreconservative means of obtaining the definitive diagnosisand definitive treatment.13,15,16 However, the technique isdifficult to execute; patients still have to suffer the surgi-cal damage resultant from the insertion of the arthroscopeinto the joint cavity,4 and some loose bodies are bigenough to inable this technique. Moreover, not all the sur-gical services dispose from the equipment. Various othertreatments have been used. For a long time, completeremoval of the synovium associated or not with condylec-tomy or condylotomy was the main therapy for thispathology.2 Nowadays, this radical approach is rarelyindicated. More conservative procedures such as arthro-tomy and removal of the loose bodies, partial or total syn-ovectomy, and, particularly, if both joint compartmentsare affected or if the disk is damaged beyond functionalrepair, diskectomy are the treatment of choice.3,12,13,16

In the case reported, the surgical approach enabled theremoval of either little or big loose bodies. As no signifi-cant alterations were found in the synovium, disk orcondyle, a very conservative surgical procedure wastaken, with no need of synovium or disk removal.Radiopacities of the TMJ should be thoroughly investi-gated as some signals and symptoms may be not presentor combined, taking months or even years to confirm adiagnosis.10

References

1. Mandrioli S, Polito J, Denes SA, Clauser L: Synovial chondromatosis of thetemporomandibular joint. J Craniofac Surg 2007; 18:1486-1488.

2. Bell G, Sharp CW, Fourie LR, Hutchinson D: Conservative surgical manage-

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ment of synovial chondromatosis. Oral Surg Oral Med Oral Pathol OralRadiol Endod. 1997; 84:592-593.

3. Fujita S, Iizuka T, Yoshida H, Segami N: Transforming growth factor andtenascin in synovial chondromatosis of the temporomandibular joint.Report of a case. Int J Oral Maxillofac Surg 1997; 26:258-259.

4. Ikebe T, Nakayama E, Shinohara M, Takeuchi H, Takenoshita Y: Synovialchondromatosis of the temporomandibular joint: the effect of interleukin-1on loose-body-derived cells. Oral Surg Oral Med Oral Pathol Oral RadiolEndod 1998; 85:526-531.

5. Karlis V, Glickman RS, Zaslow M: Synovial chondromatosis of the tem-poromandibular joint with intracranial extension. Oral Surg Oral Med OralPathol Oral Radiol Endod 1998; 86:664-666.

6. Mendonca-Caridad JJ, Schwartz HC: Synovial chondromatosis of the tem-poromandibular joint: arthroscopic diagnosis and treatment of a case. JOral Maxillofac Surg 1994; 52:624-625.

7. Petito AR, Bennett J, Assael LA, Carlotti AE Jr.: Synovial chondromatosis ofthe temporomandibular joint: varying presentation in four cases. Oral SurgOral Med Oral Pathol Oral Radiol Endod 2000; 90:758-764.

8. Psimopoulou M, Karakasis D, Magoudi D, Tzarou V, Eleftheriadis I:Synovial chondromatosis of the temporomandibular joint. Br J OralMaxillofac Surg 1998; 36:317-318.

9. Reinish EI, Feinberg SE, Devaney K: Primary synovial chondromatosis ofthe temporomandibular joint with suspected traumatic etiology. Report of acase. Int J Oral Maxillofac Surg 1997; 26:419-422.

10. Sato J, Segami N, Suzuki T, Yoshitake Y, Nishikawa K: The expression offibroblast growth factor-2 and fibroblast growth factor receptor-1 in chon-drocytes in synovial chondromatosis of the temporomandibular joint.Report of two cases. Int J Oral Maxillofac Surg 2002; 31:532-536.

11. Holmlund AB, Eriksson L, Reinholt FP: Synovial chondromatosis of the tem-poromandibular joint: clinical, surgical and histological aspects. Int J OralMaxillofac Surg 2003; 32:143-147.

12. Miyamoto H, Sakashita H, Miyata M, Kurita K: Arthroscopic diagnosis andtreatment of temporomandibular joint synovial chondromatosis: report of acase. J Oral Maxillofac Surg 1996; 54:629-631.

13. von Lindern JJ, Theuerkauf I, Niederhagen B, Berge S, Appel T, Reich RH:Synovial chondromatosis of the temporomandibular joint: clinical, diag-nostic, and histomorphologic findings. Oral Surg Oral Med Oral PatholOral Radiol Endod 2002; 94:31-38.

14. Felices RR, Giordano OA: Condromatosis sinovial de la ATM. Rev AsocOdontol Arg 2004; 92:163.

15. Wise DP, Ruskin JD: Arthroscopic diagnosis and treatment of temporo-mandibular joint synovial chondromatosis: report of a case. J OralMaxillofac Surg 1994; 52:90-93.

16. Lucas JH, Quinn P, Foote J, Baker S, Bruno J: Recurrent synovial chondro-matosis treated with meniscectomy and synovectomy. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997;84:253-258.

17. Milgram JW: The classification of loose bodies in human joints. Clin Orthop1977; 124:282-291.

18. Xiang S, Rebellato J, Inwards CY, Keller EE: Malocclusion associated withosteocartilaginous loose bodies of the temporomandibular joint. J Am DentAssoc 2005; 136:484-489.

19. Yu Q, Yang J, Wayng P, Shi H, Luo J: CT features of synovial chondro-matosis in the temporomandibular joint. Oral Surg Oral Med Oral PatholOral Radiol Endod 2004; 97:524-528.

Dr. Caio Cesar de Souza Loureiro is an oral and maxillofacial resi-dent, in the Section of Oral and Maxillofacial Surgery, Hospital SantaPaula, São Paulo, Brazil.

Dr. Paula Felix Falchet is an oral and maxillofacial surgery assistantprofessor, Section of Oral and Maxillofacial Surgery, Hospital SantaPaula, São Paulo, Brazil.

Dr. Luis Fernando Lobo Leandro is chief of the Section of Oral andMaxillofacial Surgery, Hospital Santa Paula, São Paulo, Brazil.

Dr. Ricardo Raitz is a professor of the Biodentistry post graduate(M.Sc.) program of Ibirapuera University, São Paulo, Brazil; professorand chair of General Pathology at São Caetano do Sul University, SãoPaulo, Brazil.

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