Article ID: WMC002484 ISSN 2046-1690

Soft Tissue Osteochondroma of the Articular Disc ofthe Temporomandibular Joint: A Case ReportCorresponding Author:Prof. Sergio E Cury,DDS PhD, Oral Pathology - UniFOA - University of Volta Redonda, 27.310-060 - Brazil

Submitting Author:Prof. Sergio E Cury,DDS PhD, Oral Pathology - UniFOA - University of Volta Redonda, 27.310-060 - Brazil

Article ID: WMC002484

Article Type: Case Report

Submitted on:17-Nov-2011, 12:08:53 PM GMT Published on: 18-Nov-2011, 04:52:00 PM GMT

Article URL: http://www.webmedcentral.com/article_view/2484

Subject Categories:HISTOPATHOLOGY

Keywords:Soft tissue Osteochondroma, Osteochondroma, Articular disc, Temporomandibular joint, Craniofacialbones.

How to cite the article:Cury S E, Shinohara E , Oliveira R , Miyagusko J , Mitsuda S T, Martins M T, Pinto-juniorD D. Soft Tissue Osteochondroma of the Articular Disc of the Temporomandibular Joint: A Case Report .WebmedCentral HISTOPATHOLOGY 2011;2(11):WMC002484

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Soft Tissue Osteochondroma of the Articular Disc ofthe Temporomandibular Joint: A Case ReportAuthor(s): Cury S E, Shinohara E , Oliveira R , Miyagusko J , Mitsuda S T, Martins M T, Pinto-junior D D

Abstract

The authors report a rare soft tissue osteochondroma,a common benign bone tumor, of the articular disc ofthe temporomandibular jo in t (TMJ). Thehistopathological findings were analyzed. The mostimportant is that this is an unusual location of thetumor, not yet described in the English literature.

Introduction

Osteochondroma (OC) is one of the most commonbenign neoplasms; it usually develops in long bonesand very rarely occurs in craniofacial region[1,2]. Itrepresents approximately 35% to 50% of all benigntumors, and 8% to 15% of all primary bone tumors[3].It is defined as an osteocartilaginous exostosis withcartilage-capped bony protrusion on the externalsurface of a bone[4]. It has been described in the head,cranial base, jaw, maxillary sinuses, condyle, ramus,body, coronoid process and symphyseal mandibularregion[5].The etiology of OC remains controversial; neoplastic,developmental and reparative origins have beendiscussed[1,6].The most common symptom in the craniofacial regionis limited mouth opening and facial deformity; due tothe slow development of the disease, patients withcomplaints of pain and limited mouth opening may betreated for a misdiagnosis of temporomandibular (TMJ)disorder[7].Soft tissue or extraskeletal OC are rather unusualosteocartilaginous lesions that arise in the soft tissuesadjacent to the joint with no bony continuity. Theirrecognition is important to avoid unnecessaryaggressive surgical management as marginal excisionis adequate. Most reported lesions affected the handsand feet and presented as small discrete calcifiedmasses rarely exceeding 2cm[8].Histologically, the tumor includes endochondralossification regions enclosed by hyaline cartilage.Growth of an OC is similar to that occurring at theepiphysis, with the cartilage cap acting as theepiphyseal plate. Chondrocytes migrate to the centerto form cancellous bone[9].Radiographically, the lesion is radiopaque and easily

identified on computed tomography (CT). Due to theirdistinct borders, these lesions can be easily followedradiographical ly with CT as wel l as plainradiography[1].

Case Report(s)

A 46-year-old white man was assisted by theMaxillofacial Surgery Group at Albert Einstein Hospital,São Paulo, Brazil, for evaluation of asymptomaticunilateral enlargements of the right TMJ region. Thepatient also presented with complaints of aprogressively changing bite and had an associatedmild facial asymmetry. On physical examination, hedid not present limited mouth opening, yet he had rightposterior and anterior crossbite. His mandible wasslightly deviated to the left side (Illustration1 A). Onpalpation, a palpable mass was observed in the softtissues at the upper portion of the articular disc of theTMJ. The mass had appeared spontaneously 6months previously and had grown in recent months.There was no history of trauma and any crepitationand pain in the TMJ was observed.A maxillofacial computed tomography (CT) was madeto assess the lesion and its relationship to the adjacentstructures. On CT, the right TMJ showed the articulardisc enclosed by a dense well-defined calcified masswith defined borders but not attached to themandibular condyle. It was confirmed by obliquelateral radiography of the mandible (Illustration 1 B, Cand D).The mass was surgically removed via a slightlyextended preauricular-temporal incision with exposureof the lesion area. The exophytic lesion wasapproximately 3cm to4cm in size and had acartilaginous appearance. No clear association withfacet joints was demonstrated and it was confirmedduring surgery that the mass was totally extraskeletal.After surgery, the coronoid process and mandibularcondyle were preserved (Illustration2 Aand B).Histological examination was undertaken at the OralPathology Department at the Dental School ofUniversity ofSão Paulo. The sections showed that thebulk of the lesion was made up of mature bonytrabeculae located beneath the well-formed maturehyaline cartilage with isogenic groups and singlechondrocytes, surrounded by the fibrous capsule at

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the periphery. Active endochondral ossification wasobserved at the interphase between cartilage andbone (Illustration 2 C, D and E). There was nochondroblastic or chondrogenic differentiation and nocellular pleomorphism or nuclear atypia were observed.Based on the gross and histological features, adiagnosis of soft tissue osteochondroma wasconfirmed.No recurrence was recorded after 6-month follow-up.

Discussion

We presented a rare case of sof t t issueosteochondroma of a 46-year-old white man, locatedin the articular disc of the temporomandibular joint, notdescribed in the English literature so far. The tumorshowed clinical, histological and radiographiccharacteristics of osteochondroma, yet the etiology ofthis lesion in the articular disc is not yet clear.OC is a benign neoplasm commonly arising from theends of long bones, demonstrating mature bone withcartilaginous cap and continuation of the medullarycavity with that of the long bone. Infrequently,osteochondral neoplasms arise in soft tissues, but thecause of their origin in soft tissues remainscontroversial[10]. The concept of soft tissue OC wasfirst introduced in 1958 by Jaffe, who used thesynonymous terms para-articular chondromas andintracapsular chondromas to describe osteochondralmetaplasia occurring in fibrous joint capsule or softtissue adjacent to the joint[11]. Reith et al.[12]suggested the following criteria for a lesion to bediagnosed as soft tissue OC: (1) the lesion presentsas a single, dominant mass, both radiographically andgrossly; (2) the mass consists histopathologically ofboth bone and cartilage, organized in a similar manneras conventional osteochondromas; and (3) the lesionis not intra-articular, that is, it does not arise within thesynovial lining of a joint.Extraskeletal OC can arise from fibroblasts in theconnective tissue distant from bones and joints due tounknown stimuli. The tumors typically occur in adults,usually without antecedent trauma[13,14].The literature presents different possibilities for thepathogenesis of OC, including neoplastic,developmental or reparative origins[1,15]. Identifyingthe origin poses obvious difficulties.The tumor in this case was located in the articular discof the TMJ, without history of trauma; no obviouscontinuity was found with the mandibular condyle in allimages or during the procedure itself. Differentialdiagnoses such as synovial osteochondromatosis,chondrosa rcoma, myos i t i s oss i f i cans ,

pseudomalignant osseous tumor, ossifyingfibromyxoid tumor, and extraskeletal osteosarcomaare reserved for discrete soft-tissue masses thatcontain mature ossification. Anatomopathologicalfeatures of the present case excluded the possibility ofthese lesions and it is essential to avoid unnecessaryaggressive surgical procedures.

References

1 . Ward BB , P i res CAS, Fe inbe rg SE .Osteochondromas of the Mandible: Case Reports andRationale for Treatment. J Oral Maxillofac Surg, 2005;63:1039-1044.2. Sakai H, Minemura T, Ito N, Miyazawa H, KurashinaK. Isolated osteochondroma near the mandibularangle. Int J Oral Maxillofac Surg. 2006 (article inpress).3. Wolford LM, Mehra P, Franco P. Use ofConservative Condylectomy for Treatment ofOsteochondroma of the Mandibular Condyle. J OralMaxillofac Surg, 2002; 60:262-268.4. Ayd?n MA, Kuçukcelebi A, Say?lkan S, CelebiogluS. Osteochondroma of the Mandibular Condyle:Report of 2 Cases Treated With Conservative Surgery.J Oral Maxillofac Surg, 2001: 59:1082-089.5. Villanueva J, Gonzalez A, Cornejo M, Nunez C,Encina S. Osteochondroma of the coronoid process.Med Oral Patol Oral Cir Bucal. 2006;11(3):289-91.6. Peroz HJ, Scholman BH. Osteochondroma of themandibular condyle: a case report. Int. J. OralMaxillofac. Surg. 2002; 31: 455–456.7. Emekli U, Aslan A, Onel D, Izmeci OC, Demiryont M.Osteochondroma of the Coronoid Process (Jacob’sDisease) J Oral Maxillofac Surg, 2002; 60:1354-56.8. Singh R, Sharma AK, Magu NK, Kaur KP, Sen R,Magu S. Extraskeletal osteochondroma in the nape ofthe neck: a case report. J Orthop Surg (Hong Kong).2006 Aug;14(2):192-5.9. Rubin E, Gorstein F, Rubin R, Schwarting S,Strayer D. Rubin's Pathology: ClinicopathologicFoundations of Medicine. 4th Ed.Philadelphia,PA,Lippincott, Willians & Wilkins, 2005, 1346p.10. Chung EB, Enzinger FM. Chondroma of soft parts.Cancer 1978;41:1414–424.11. Maheshwari AV, Jain AK, Dhammi IK.Extraskeletal paraarticular osteochondroma of theknee--a case report and tumor overview Knee. 2006Oct;13(5):411-4.12. Reith JD, Bauer TW, Joyce MJ. Paraarticularosteochondroma of the knee: report of 2 cases andreview of l i terature. Clin Orthop Relat Res1997;334:225–32.

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13. Gayle EL, Morrison WB, Carrino JA, Parsons TW,L iang CY, S tevenson A . Ex t raske le ta losteochondroma of the foot. Skeletal Radiol1999;28:594–8.14. Gulati Y, Maheshwari A, Sharma V, Mattoo R,Arora D, Gupta N. Extraskeletal oeteochondroma ofthe thigh: a case report. Acta Orthop Belg2005;71:115–8.

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Illustrations

Illustration 1

Preoperative photograph. Mandible with slight deviation to the left side (A); Computed tomography scan showing irregular bonyoutgrowth at the right articular disc (B and C); Oblique radiography showing the unaffected mandibular condyle (D).

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Illustration 2

Preauricular-temporal incision (A); Lesion area showing the unaffected and preserved mandibular condyle (B); Endochondralossification regions enclosed by hyaline cartilage -hematoxylin and eosin staining, original magnification 80X (C and D); Low-powermagnification 400X showing endochondral ossification (E).

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