Access the full text.
Sign up today, get DeepDyve free for 14 days.
Synovial chondromatosis is a benign disease that only rarely affects the temporomandibular joint. When it does, disease is usually confined to the joint space itself but can occasionally extend beyond the joint capsule into the parotid gland, temporal bone, or cranium. The local clinical behavior, radiographic appearance, and histopathologic features can combine to create the appearance of a malignant lesion. We report a case of synovial chondromatosis that affected the temporomandibular joint and presented as an external auditory canal mass. The lesion was thought to be a chondrosarcoma prior to the definitive resection. Pitfalls in the diagnosis and management of synovial chondromatosis are discussed.Synovial chondromatosis (SC) is a monoarticular arthropathy characterized by primary chondrometaplasia of the synovium.In the temporomandibular joint (TMJ), disease confined to the joint space should be differentiated from other causes of loose body formation. Distinction of this metaplastic process from a benign or malignant neoplasm is problematic when disease extends beyond the joint capsule or is locally destructive.REPORT OF A CASEA 62-year-old woman presented with a 1-week history of sharp, deep-seated, right-sided otalgia associated with scant, bloody otorrhea. A soft tissue mass was found in her right external auditory canal, and after an initial transcanal excision, it rapidly recurred. On referral to the University of Texas Southwestern Medical Center at Dallas, the patient was found to have a mass in the anteroinferior external auditory canal that appeared to be coming from the glenoid fossa.A computed tomographic scan revealed a locally destructive bone lesion measuring 2.8 × 2.3 cm in dimension in the right glenoid fossa. The lesion extended anterior, medial, and posterior to the mandibular condyle, but the condyle did not appear eroded. The posterior wall of the glenoid fossa was disrupted, with extension of a small nodule of tissue into the anterior external auditory canal (Figure 1and Figure 2).Figure 1.Coronal computed tomographic scan, bony algorithm, demonstrating a destructive lesion in the right glenoid fossa.Figure 2.Axial computed tomographic scan, bony algorithm, demonstrating extension of disease through the bone of the posterior glenoid fossa into the anterior external auditory canal.Frozen-section evaluation of an open biopsy specimen from the right glenoid fossa revealed atypical cartilage with nuclear atypia originating within synovial tissue (Figure 3). The frozen-section diagnosis was consistent with chondrosarcoma. The patient underwent a combined infratemporal fossa and middle cranial fossa en bloc extradural resection of the lesion along with a superficial parotidectomy and condylectomy. Reconstruction was accomplished with a lateral thigh fasciocutaneous free-tissue transfer. After pathologic examination of the entire specimen and considerable discussion, including consultation with colleagues at other institutions, the final pathologic diagnosis was SC (Figure 4).Figure 3.Frozen section demonstrating hyaline cartilage with mild nuclear atypia and hyperchromasia (hematoxylin-eosin, original magnification ×200).Figure 4.Permanent section showing synovial chondromatosis with nodular proliferation of hyaline cartilage extending into adjacent connective tissue with a pushing border (hematoxylin-eosin, original magnification ×100).The patient continues to do well 3 years after surgery, without any clinical or radiographic evidence of disease recurrence. Facial nerve function, mastication, and appearance are normal.COMMENTSynovial chondromatosis is a noninflammatory, monoarticular arthropathy that has a prediliction for large diarthroidial joints. Involvement of the TMJ is uncommon. Symptoms are usually chronic and progress over months to years, and commonly include TMJ pain, preauricular swelling, and TMJ dysfunction.This disease is more common on the right side.Although large-joint involvement is more common in males, TMJ involvement is more common in females.The cause is currently unknown, but prior trauma has been implicated as a possible initiating factor.Although associated calcium pyrophosphate crystals within the TMJ have been reported,there is no known association of SC with pseudogout.Macroscopically, SC is characterized by multiple, hard, smooth-surfaced, gray-white nodules floating freely in the joint space.The pathogenesis of SC is best understood by a review of the histologic progression. Synovial chondromatosis has been considered to be a metaplastic rather than a neoplastic disease. It is believed to arise from primary chondrometaplasia within the subintimal connective tissue of the synovial membrane. Preexisting gross or histologic joint abnormalities that initiate the metaplasia should not be evident. These changes lead to the formation of cartilaginous nodules (known as loose bodies) that become pedunculated and detached from the synovium. The chondrocytes found within the hyalinized matrix of these loose bodies are arranged in clusters with abundant intervening matrix. The chondrocytes can be multinucleated and commonly have a moderate amount of cytologic atypia.Confounding this generally accepted view of SC as a metaplastic process, however, are recent cytogenetic data suggesting that SC may be a clonal proliferation.The differential diagnosis of loose bodies found within the TMJ includes SC, osteoarthritis, rheumatoid arthritis, osteochondritis dissecans, tuberculous or pyogenic arthritis, neurotropic arthritis, and avascular necrosis.Histologically, chondrocyte metaplasia must be demonstrated to distinguish SC from the other diagnostic possibilities.The number of loose bodies may also suggest the diagnosis. Von Arx et alreported that 80% of patients with SC that affects the TMJ have more than 10 loose bodies, whereas the other conditions typically have fewer than 3. The nodules can be so abundant that they appear to form a solid mass within the joint space.Radiographic evaluation can be problematic. Carls et alfound that radiographic findings did not suggest SC in 5 of 7 patients when the diagnosis was made during arthroscopy. Temporomandibular joint radiographs have a limited role owing to variable calcification of loose bodies and superimposition of cranial bones.Computed tomographic findings include a change in joint space size, high-density foci, erosions of the glenoid fossa, and flattening or sclerosis of the condyle.Magnetic resonance imaging can detect joint capsule expansion and intra-articular calcifications.Diagnostic arthroscopy is an increasingly important diagnostic tool because of the recognized limitations of imaging.Extracapsular extension with involvement of surrounding structures is rare but can be easily mistaken for a benign or malignant neoplasm. Anterior or lateral extension can present as a parotid mass and has been histologically mistaken to be a benign mixed tumor.Posterior extension can present as an external auditory canal or middle ear lesion. Extension superiorly into the middle cranial fossa through the glenoid fossa roofor infratemporal fossacan occur. Disease that extends into the temporal bone or skull base tends to behave in a locally destructive fashion. Although the lesion tends to remain extradural,massive bone erosionand facial nerve paralysishave been reported. In the more common extremity sites, such as the knee, bone and soft tissue involvement by SC is a well-recognized characteristic. Thus, this gross feature should not be used alone as a defining characteristic for malignancy.Computed tomography or magnetic resonance imaging can provide assessment for extra-articular extension, and magnetic resonance imaging is especially helpful in the evaluation of dural proximity when intracranial extension is suspected.Although SC is a benign lesion, the cytologic atypia may be mistaken for a chondrosarcoma. A chondrosarcoma in the TMJ region arises more commonly from the condyle (13 reported cases)than from the synovium (2 reported cases).Nonetheless, chondrosarcoma can arise as a primary malignancy from the synovium or from preexisting SC. Bertoni et aldescribed the histologic features favoring a diagnosis of synovial chondrosarcoma over SC. These features included loss of a clustering growth pattern, myxoid change in the matrix, areas of necrosis, and spindling at the periphery of chondroid lobules. Permeation of bone rather than a pushing border is also consistent with malignancy.Radiographic imaging in this region may have limited benefit for distinguishing SC from chondrosarcoma. Computed tomography and magnetic resonance imaging were incorporated into treatment planning for the 2 reported cases of synovial chondrosarcoma of the TMJ. Each case was preoperatively misdiagnosed as SC.The 13 cases of condylar chondrosarcoma reviewed by Sesenna et alhad TMJ imaging characteristics that were similar to those of SC.The treatment for SC consists of surgical exploration with removal of all the loose bodies and affected synovium.Arthrotomy may be necessary, but arthroscopy can be used to remove limited disease. The disadvantages of arthroscopy include technical difficulty, size limitation of fragments removed through the instruments (2 mm),and limitation to the upper joint space.Condylectomy is necessary only if improved surgical access is needed.Although SC is a pathologically benign lesion, treatment for disease with extra-articular extension may require skull base techniques for complete resection. This assures local control and allows the pathologist to examine the entire specimen for malignancy.In this case, a large skull base resection and reconstruction was performed for a benign lesion. Had the correct diagnosis been determined ahead of time, a smaller operation might well have sufficed. However, it needs to be emphasized that complete resection is important when treating chondromatosis. Although benign, these lesions can demonstrate locally aggressive behavior and present some risk for malignant degeneration. Consequently, skull base techniques may be required to ensure a safe, complete resection. The margins can probably be considerably smaller, since the lesions are benign. In this particular case, it is possible that less aggressive mobilization of the facial nerve could have been possible if it had been known in advance that the lesion was a benign one that could be appropriately managed without using an en bloc technique.WEFeePWindhorstRWigginsLPangSynovial chondromatosis of the temporomandibular joint.Otolaryngol Head Neck Surg.1979;87:741-748.JBlankestijnAKPandersAVermeyAJScherpbierSynovial chondromatosis of the temporomandibular joint.Cancer.1985;55:479-485.DPVon ArxMTSimpsonPBatmanSynovial chondromatosis of the temporomandibular joint.Br J Oral Maxillofac Surg.1988;26:297-305.LGdeBontRSBLiemGBoeringSynovial chondromatosis of the temporomandibular joint: a light and electron microscopic study.Oral Surg Oral Med Oral Pathol.1988;66:593-598.FMertensKJonssonHWillenChromosome rearrangements in synovial chondromatous lesions.Br J Cancer.1996;74:251-254.RSciotPDal CinJBellemansISamsonHVan de BergheBVan DammeSynovial chondromatosis: clonal chromosome changes provide further evidence for a neoplastic disorder.Virchows Arch.1998;433:189-191.SSunEHelmyRBaysSynovial chondromatosis with intracranial extension.Oral Surg Oral Med Oral Pathol.1990;70:5-9.KThompsonHCSchwartzJWMilesSynovial chondromatosis of the temporomandibular joint presenting as a parotid mass: possibility of confusion with benign mixed tumor.Oral Surg Oral Med Oral Pathol.1986;62:377-80.FRCarlsAvon HochstetterWEngelkeHFSailerLoose bodies in the temporomandibular joint.J Craniomaxillofac Surg.1995;23:215-221.JMvan IngenKde ManIBakriCT diagnosis of synovial chondromatosis of the temporomandibular joint.Br J Oral Maxillofac Surg.1990;28:164-167.LBHeffezImaging of internal derangements and synovial chondromatosis of the temporomandibular joint.Radiol Clin North Am.1993;31:149-162.HMiyamotoHSakashitaMMiyataKKuritaArthroscopic diagnosis and treatment of temporomandibular joint synovial chondromatosis.J Oral Maxillofac Surg.1996;54:629-631.PDQuinnDCStantonJWFooteSynovial chondromatosis with cranial extension.Oral Surg Oral Med Oral Pathol.1992;73:398-402.LARosatiCStevensSynovial chondromatosis of the temporomandibular joint presenting as an intracranial mass.Arch Otolaryngol Head Neck Surg.1990;116:1334-1337.SRNokesPSKingRGarcia JrMLSilbigerJDJones IIINDCastellanoTemporomandibular joint chondromatosis with intracranial extension: MR and CT contributions.AJR Am J Roentgenol.1987;148:1173-1174.FBertoniKKUnniJWBeaboutFHSimChondrosarcomas of the synovium.Cancer.1991;67:155-162.EADolanJBVoglerJCAngelilloSynovial chondromatosis of the temporomandibular joint diagnosed by magnetic resonance imaging.J Oral Maxillofac Surg.1989;47:411-413.ESesennaATullioSFerrariChondrosarcoma of the temporomandibular joint.J Oral Maxillofac Surg.1997;55:1348-1352.RGMerrillWYungJShamlooSynovial chondrosarcoma of the temporomandibular joint.J Oral Maxillofac Surg.1997;55:1312-1316.TIchikawaMMiyauchiHNikaiKYoshigaSynovial chondrosarcoma arising in the temporomandibular joint.J Oral Maxillofac Surg.1998;56:890-894.Accepted for publication August 12, 1999.Corresponding author: Brian Nussenbaum, MD, Department of Otolaryngology, University of Texas Southwestern Medical Center at Dallas, 5323 Harry Hines Blvd, Dallas, TX 75235-9035.
JAMA Otolaryngology - Head & Neck Surgery – American Medical Association
Published: Dec 1, 1999
Access the full text.
Sign up today, get DeepDyve free for 14 days.