Synovial chondromatosis (SC) is a benign but proliferative disorder of the synovium characterized by cartilaginous metaplasia of subsynovial connective tissue, with subsequent formation of intra-articular loose bodies. These nodules may calcify or ossify, leading to chronic mechanical symptoms and secondary degenerative changes. Although SC most frequently affects large joints such as the knee, hip, and elbow, involvement of the temporomandibular joint (TMJ) is extremely rare, accounting for less than 3% of all cases reported in literature [1]. The exact pathogenesis of SC remains uncertain. Milgram proposed a triphasic classification based on histological progression: Stage I (active intrasynovial disease without loose bodies), Stage II (transitional stage with active synovial proliferation and loose body formation), and Stage III (quiescent disease with numerous intra-articular loose bodies and inactive synovium) [2]. The condition may also be classified into primary SC, arising in a previously normal joint, and secondary SC, occurring in association with trauma, osteoarthritis, or other inflammatory arthropathies [3]. Clinically, TMJ-SC is challenging to diagnose because of its insidious onset and overlapping presentation with common temporomandibular disorders (TMD). Patients typically complain of preauricular pain, joint swelling, restricted mouth opening, and sometimes deviation on mandibular movement [4]. These symptoms are non-specific and may mimic internal derangement or degenerative arthritis. In most series, diagnosis is delayed by several months to years, during which the disease progresses and intra-articular loose bodies gradually calcify, becoming radiographically visible [5]. Female predominance and onset during the fourth and fifth decades of life are consistent epidemiological findings across reported cohorts [6]. Radiographic evaluation plays a pivotal role in recognition of TMJ-SC. Conventional plain radiographs are of limited diagnostic value, particularly in early disease, because non-calcified nodules are radiolucent. Computed tomography (CT) and cone-beam CT (CBCT) are regarded as the best modalities for detecting mineralized loose bodies and cortical changes in the glenoid fossa and articular eminence [7]. On the other hand, magnetic resonance imaging (MRI) is superior in identifying non-calcified nodules, synovial proliferation, and joint effusion, thereby facilitating diagnosis in early or Stage I disease [8]. Combined use of CT/CBCT and MRI thus provides complementary information for both diagnosis and preoperative planning. One of the most consistent imaging hallmarks of TMJ-SC is the localization of lesions to the superior joint compartment. In retrospective imaging studies, up to 90% of patients demonstrated disease confined to the superior space, with expansion and remodeling of the glenoid fossa and articular eminence but relatively sparing of the mandibular condyle [9]. This compartmental predilection not only aids in diagnosis but also influences surgical planning, as arthroscopic removal is typically feasible when the disease remains within the superior joint. The presence of multiple calcified intra-articular loose bodies with “ring-and-arc” or “popcorn” mineralization patterns on CT strongly favors SC, whereas more aggressive bony destruction with soft tissue extension raises suspicion for chondrosarcoma [10]. Management of TMJ-SC is surgical. The primary goal is the removal of intra-articular loose bodies, with or without synovectomy. Arthroscopic approaches are increasingly favored for lesions confined to the superior joint compartment, offering the advantages of minimal invasiveness, rapid recovery, and reduced morbidity [6]. Open approaches remain indicated for extensive disease, recurrent cases, or extra-articular extension. Recurrence is uncommon but may occur if proliferative synovium remains or if loose bodies are incompletely removed [3]. Despite its benign nature, TMJ-SC significantly affects patient quality of life and functional ability. Moreover, its radiographic similarity to malignant processes such as chondrosarcoma underscores the importance of accurate recognition. A better understanding of its clinical and imaging features is therefore essential for oral and maxillofacial surgeons, radiologists, and dental practitioners to avoid diagnostic delays and optimize management outcomes. The present retrospective study analyzes institutional cases of TMJ-SC to delineate clinical presentation patterns, highlight consistent imaging findings, and evaluate treatment outcomes. By comparing our experience with earlier published series, the study aims to contribute to a more comprehensive understanding of this rare but important condition.

This was a retrospective observational study conducted in the Department of Oral and Maxillofacial Surgery and Oral Radiology of a tertiary care teaching hospital. The study period extended over 10 years. Institutional approval was obtained prior to data collection. Hospital archives were screened for patients with a histopathologically confirmed diagnosis of synovial chondromatosis of the temporomandibular joint (TMJ-SC). Inclusion criteria were: 1. Patients with clinical records, preoperative imaging, and histopathological confirmation of TMJ-SC. 2. Both genders and all age groups. 3. Patients treated surgically (arthroscopy or open synovectomy). Exclusion criteria were: 1. Incomplete records or unavailable preoperative imaging. 2. Cases with recurrent disease already treated outside the institution. 3. Patients with concomitant systemic arthropathies. Data Collection The following data were extracted from medical records: • Demographic details: age, sex, laterality of involvement. • Clinical features: chief complaints, duration of symptoms, and functional impairment. • Imaging findings: type of imaging performed, localization of lesion within the joint compartments, number and morphology of loose bodies, presence of joint effusion, calcification pattern, and osseous changes. • Surgical management: approach used (arthroscopy or open synovectomy), intraoperative findings, and recurrence during follow-up. Statistical Analysis Descriptive statistics were used. Continuous variables (age, duration of symptoms) were expressed as means with standard deviations. Categorical variables (sex distribution, clinical symptoms, imaging findings) were presented as frequencies and percentages.

Table 1. Demographic and Clinical Features of Patients with TMJ-SC (n=18) Parameter Findings Mean age (years) 44.6 ± 9.2 (range 28–62) Gender distribution Female: 12 (66.7%); Male: 6 (33.3%) Laterality Left: 11 (61.1%); Right: 7 (38.9%); Bilateral: 0 Duration of symptoms Mean: 14.2 months (range 6–48) Pain 16 (88.9%) Swelling 11 (61.1%) Restricted mouth opening (<30 mm) 12 (66.7%) Joint sounds (click/crepitus) 5 (27.8%) Deviation on opening 6 (33.3%) A total of 18 patients with TMJ-SC fulfilled the inclusion criteria. The age range was 28–62 years, with a mean of 44.6 ± 9.2 years. There was a clear female predominance (12 females, 6 males; ratio 2:1). Laterality assessment showed left-sided involvement in 11 cases (61.1%) and right-sided in 7 cases (38.9%). No bilateral cases were identified. The most common presenting symptom was preauricular pain (16/18, 88.9%). Swelling was noted in 11 patients (61.1%), while restricted mouth opening (<30 mm) was documented in 12 patients (66.7%). Other features included joint sounds such as clicking or crepitus (5 patients, 27.8%) and mandibular deviation on opening (6 patients, 33.3%). The mean duration of symptoms prior to diagnosis was 14.2 months (range 6–48 months). Table 2. Imaging Characteristics of TMJ-SC (n=18) Imaging Parameter Findings Imaging modality CBCT: 8 (44.4%); CT: 6 (33.3%); MRI: 4 (22.2%) Compartment involved Superior joint space: 16 (88.9%); Both compartments: 2 (11.1%) Calcified loose bodies 14 (77.8%) Mineralization pattern Ring-and-arc: 5 (27.8%); Popcorn: 6 (33.3%); Irregular: 3 (16.7%) Osseous changes Glenoid/eminence sclerosis/remodeling: 10 (55.6%); Condylar erosion: 4 (22.2%) MRI findings (n=4) Mass lesions: 4 (100%); Effusion: 3 (75%); Non-calcified loose bodies: 2 (50%) All patients underwent imaging evaluation. Cone-beam CT (CBCT) was performed in 8 cases, multislice CT in 6 cases, and MRI in 4 cases. • Location: In 16 patients (88.9%), lesions were confined to the superior joint space, while 2 patients (11.1%) had involvement of both superior and inferior compartments. • Calcifications: Calcified loose bodies were observed in 14 patients (77.8%). Morphologically, 5 cases (27.8%) showed a ring-and-arc pattern, while 6 cases (33.3%) demonstrated popcorn-like calcifications. The remainder showed irregular mineralization. • Osseous changes: Cortical sclerosis and remodeling of the articular eminence and glenoid fossa were noted in 10 patients (55.6%). Condylar surface erosions were identified in 4 patients (22.2%), but gross condylar destruction was absent. • MRI findings: In the 4 patients with MRI, all demonstrated intra-articular mass lesions; joint effusion was seen in 3 cases (75%), and non-calcified loose bodies were visible in 2 cases (50%). Table 3. Distribution of Patients by Milgram Staging (n = 18) Stage Pathological description No. of patients (%) Clinical features Imaging characteristics Stage I Active synovial proliferation; no free bodies 3 (16.7%) Pain, mild swelling; short duration MRI: synovial thickening; no calcifications Stage II Transitional; active synovium with pedunculated or detached bodies 9 (50.0%) Pain, restricted mouth opening, deviation CT/CBCT: partial calcifications; MRI: nodules + effusion Stage III Quiescent; multiple loose bodies; synovium inactive 6 (33.3%) Long-standing swelling, marked limitation CT/CBCT: multiple calcified nodules; joint space widening Histopathological examination of resected specimens allowed classification according to Milgram’s three stages of synovial chondromatosis. In our cohort, Stage II (transitional) was the most frequent, observed in 9 patients (50.0%). Stage III (quiescent with multiple loose bodies) accounted for 6 patients (33.3%), while Stage I (active intrasynovial proliferation without loose bodies) was less common, seen in 3 patients (16.7%). Patients in Stage I presented with relatively shorter symptom duration (mean 8 months) and non-calcified nodules detectable primarily on MRI. Stage II patients typically demonstrated mixed features, with both proliferative synovium and detached loose bodies. Stage III patients often had longer disease histories, with well-calcified intra-articular bodies and associated osseous remodeling. Table 4. Treatment Modalities and Outcomes in TMJ-SC (n = 18) Treatment modality No. of patients (%) Post-op interincisal opening (mean) Complications Recurrence Arthroscopic synovectomy 10 (55.6%) 37 mm (↑13 mm from baseline) None significant 1 (10.0%) Open synovectomy 8 (44.4%) 35 mm (↑13 mm from baseline) Temporary facial nerve weakness (1); hematoma (1) 0 Overall 18 (100%) – – 1 (5.6%) All patients underwent surgical intervention. Arthroscopic synovectomy with loose body removal was performed in 10 patients (55.6%), while open preauricular synovectomy was employed in 8 patients (44.4%). The choice of approach was determined by the extent of intra-articular involvement and surgeon preference. • Arthroscopy: Allowed complete removal of loose bodies confined to the superior compartment. Postoperative recovery was faster, with mean improvement in interincisal opening from 24 mm preoperatively to 37 mm at 6-month follow-up. No immediate recurrences were noted. • Open surgery: Indicated in patients with extensive disease, including those with involvement of both joint compartments or marked osseous remodeling. Mean interincisal opening improved from 22 mm preoperatively to 35 mm at 6 months. Two patients (25% of open group) developed postoperative complications—temporary facial nerve weakness (n=1) and hematoma (n=1)—both resolved with conservative management. • Recurrence: Over a mean follow-up of 28 months (range 12–60), only one recurrence (5.6%) was observed, in a patient treated initially with arthroscopy. The recurrent case was managed successfully by subsequent open synovectomy.

Synovial chondromatosis of the temporomandibular joint (TMJ-SC) is an uncommon entity that often presents a diagnostic dilemma due to its non-specific symptoms and overlap with common temporomandibular disorders. The findings of this retrospective analysis are consistent with prior studies, reaffirming the characteristic demographic profile, clinical manifestations, and imaging hallmarks of TMJ-SC. The discussion will contextualize our results within existing literature, highlight diagnostic challenges, and explore implications for management. Demographic and Clinical Patterns In this series, the mean age at presentation was in the mid-forties, with a distinct female predominance. These findings align with published reports that consistently note TMJ-SC as a disease of middle-aged adults, more commonly women [11]. The reasons for this gender predisposition remain speculative but may relate to hormonal influences on synovial tissue or differential patterns of TMJ loading between genders. The most common presenting symptoms in our cohort were preauricular pain, swelling, and restricted mouth opening. These clinical features are well documented in literature and reflect the chronic irritation and space-occupying nature of intra-articular loose bodies [12]. Joint sounds such as clicking and crepitus were less frequent but, when present, often prompted patients to seek earlier consultation. Importantly, the mean duration of symptoms exceeded one year in many cases, underscoring the insidious progression of disease and the likelihood of misdiagnosis as internal derangement or degenerative arthritis [13]. Imaging Characteristics and Diagnostic Value Imaging played a central role in confirming diagnosis. Our findings demonstrated that the superior joint compartment was involved in nearly 90% of cases. This observation corresponds with the compartmental predilection described in radiological series, which emphasize that loose bodies in TMJ-SC rarely extend beyond the superior joint unless advanced [14]. CT and CBCT were effective in identifying calcified nodules, with typical “ring-and-arc” or “popcorn” mineralization patterns. These features are highly suggestive of chondroid lesions and help distinguish SC from simple degenerative changes. MRI, on the other hand, was superior in detecting non-calcified nodules and joint effusion, allowing identification of early-stage disease. This complementary diagnostic role of CT and MRI has been emphasized repeatedly in prior studies [15]. A key diagnostic challenge lies in differentiating TMJ-SC from malignant lesions such as chondrosarcoma. While both conditions may present with intra-articular masses and bone remodeling, the absence of aggressive condylar destruction and marrow invasion in SC is helpful in distinction. Advanced imaging criteria, including assessment of marrow continuity and extra-articular spread, can guide differentiation, although biopsy remains the gold standard in suspicious cases [16]. Histopathological Correlation and Staging Histological staging according to Milgram remains clinically relevant. Stage II (transitional) disease was most common in our cohort, reflecting the stage at which symptoms typically prompt medical attention. This finding is consistent with earlier reports that transitional disease predominates at diagnosis [17]. Stage III, characterized by numerous calcified loose bodies, was associated with longer symptom duration and more pronounced osseous remodeling, whereas Stage I was rarely diagnosed, likely due to its subtle clinical and imaging profile. The clinical correlation of staging is important for prognosis and surgical planning. Patients in Stage I or early Stage II may benefit from earlier arthroscopic intervention, which could prevent progression to extensive remodeling and functional impairment. Treatment Approaches and Outcomes Surgical excision of loose bodies remains the cornerstone of treatment. In our study, both arthroscopic and open synovectomy achieved satisfactory results, with significant improvement in mouth opening and symptom resolution. Arthroscopy offered advantages of minimal invasiveness, faster recovery, and fewer complications, in line with the growing consensus that arthroscopy should be the first-line approach when lesions are confined to the superior compartment [18]. Open surgery, although associated with slightly higher morbidity, allowed complete clearance in cases with extensive disease or extra-articular involvement. The recurrence rate in our series was low (5.6%), comparable to that reported in other retrospective series. Recurrence typically results from incomplete removal of proliferative synovium or loose bodies, reinforcing the importance of meticulous surgical technique. Multiple recurrences, although rare, should raise suspicion for malignant transformation, a phenomenon documented in isolated cases [19]. Clinical Implications The findings of this study highlight several clinical implications. First, clinicians should maintain a high index of suspicion for TMJ-SC in patients presenting with long-standing preauricular pain, swelling, and restricted opening, especially when conventional therapies for temporomandibular disorders fail. Second, imaging strategies should be individualized: MRI is indispensable in suspected early or non-calcified disease, while CT/CBCT is preferred when calcified loose bodies are anticipated. Third, arthroscopy should be prioritized when disease is localized, while open surgery remains necessary in advanced or recurrent cases. Limitations As a retrospective study, this analysis has inherent limitations. The sample size was modest due to the rarity of TMJ-SC, and long-term follow-up beyond five years was limited in some cases. Additionally, while histopathological staging was available for all patients, interobserver variability in staging could not be excluded. Despite these limitations, the study contributes valuable institutional experience and corroborates key clinical and imaging patterns described in the literature. Future Directions Further multi-center studies with larger cohorts are warranted to refine diagnostic criteria and validate prognostic factors. The role of advanced MRI techniques, including diffusion-weighted imaging and dynamic contrast enhancement, merits exploration for distinguishing SC from malignant mimics. Additionally, long-term studies are needed to better define recurrence rates following arthroscopy versus open approaches [20-25].

Temporomandibular joint synovial chondromatosis (TMJ-SC) is a rare but clinically significant disorder that often mimics common temporomandibular conditions. The present retrospective study highlights a consistent demographic pattern of female predominance and middle-aged onset, with pain, swelling, and restricted mouth opening as dominant features. Imaging plays a decisive role: CT and CBCT reliably detect calcified loose bodies and bony remodeling, while MRI identifies early non-calcified disease and joint effusion. Histopathological correlation using Milgram’s staging confirmed that most patients present in the transitional stage, reflecting diagnostic delay until loose bodies become apparent. Surgical management, whether arthroscopic or open, produced favorable outcomes, with low recurrence. Arthroscopy offered distinct advantages in localized disease, while open surgery remained essential for extensive or recurrent involvement. In clinical practice, recognition of hallmark imaging features—particularly superior joint compartment involvement and calcified chondroid nodules—can shorten diagnostic delays and prevent unnecessary morbidity. Early surgical intervention, guided by accurate imaging, remains the key to restoring function and improving patient quality of life.

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