Benign and malignant neoplasms in temporomandibular joint (TMJ): a narrative review

Introduction

The temporomandibular joint (TMJ) is the only movable joint in the cephalic region, articulating with the mandible at the glenoid fossa of the temporal bone and the condyle of the mandible (1). The bilateral articulation of TMJ allows the mandible to function normally (1). Consequently, any pathology affecting one TMJ can lead to pain and functional complications (1). Moreover, the TMJ possesses a remarkable capacity for physiological remodeling throughout life (1,2). This adaptive ability allows it to undergo structural changes in response to various factors such as growth, aging, and functional demands, highlighting its significance in maintaining optimal oral function and overall craniofacial health (1).

TMJ can be affected by various neoplasms, both benign and malignant (1). Although tumors of the TMJ are rare, they can have significant impacts on function, appearance, and overall quality of life (1,2). The clinical presentation of tumors often overlaps with temporomandibular disorders (TMDs), leading to diagnostic challenges. An accurate and timely diagnosis is critical for effective treatment and optimal patient outcomes (2,3).

The American Academy of Orofacial Pain (AAOP) defines TMD as a group of musculoskeletal and neuromuscular conditions involving the TMJ, its masticatory muscles, and associated structures (4-6). Common symptoms include pain, limitation of mouth opening, asymmetric jaw movements, TMJ sounds, earache, tinnitus, headache, and neck pain (4-6). Musculoskeletal disorders typically respond well to conservative management, like analgesics, physical therapy, home care, and occlusal therapy (4-6). In contrast, neurological, neurovascular, neoplastic, and glandular sources of pain are highly misleading and often misdiagnosed, resulting in mismanagement that increases morbidity and mortality (2,3).

Pain is reported in 70% of cancer patients (7) and TMJ-related cancer can present with TMD-like symptoms (2). Key signs such as jaw movement limitation, preauricular tenderness, swelling, and tinnitus paresthesia in the alveolar and mental nerve regions and changes in occlusions should be thoroughly evaluated to rule out malignancy (2).

Malignancy involving the TMJ is rare but can mimic other conditions, necessitating comprehensive examination, medical history review, and clinical evaluation (2,8). TMJ tumors often manifest as progressive occlusion changes, and facial asymmetry, indicating mandibular condyle alterations, which may be evident in panoramic images (2,8,9). Morphological changes in condyle of TMJ can result from bony or cartilaginous tumors or reactive hyperplasia (2). A critical analysis of the tumor matrix pattern, margins, and periosteal reaction is necessary for accurate diagnosis (2).

This review aims to provide a comprehensive overview of the various benign and malignant tumor pathologies affecting the TMJ, detailing their clinical, radiological, and histological features. It underscores the importance of a multidisciplinary approach for accurate diagnosis and effective management. We present this article in accordance with the Narrative Review reporting checklist (available at https://joma.amegroups.com/article/view/10.21037/joma-24-25/rc).

Methods

This review evaluates benign and malignant neoplasms of the TMJ based on literature from June 1990 to June 2024. Initial search for neoplasm & TMJ articles from biomedical search engines, including PubMed, Google Scholar, and Embase resulted in 1,414. These articles were screened by two independent reviewers to select relevant articles. All the prospective studies, narrative reviews, case reports and met-analytic studies focused on malignant and benign tumors in TMJ were further evaluated to extract the clinical, radiographic, and histopathological findings.

The data extracted from the relevant articles was mainly focused on patient demographics, clinical presentation, diagnostic methods, differential diagnosis (DD), treatment options, pathological characteristics, and outcomes. This structured methodology aims to enhance understanding of TMJ neoplasms, guiding future research and clinical practice (Table 1).

Benign tumors

Osteoma

Osteoma is a rare benign tumor characterized by mature bone tissue proliferation, primarily occurring in craniofacial bones, with few cases reported in the TMJ and mandibular region (3,8,10).

TMJ condylar osteomas originate from the periosteum (periosteal osteoma) or the endosteum (endosteal osteoma) and are classified as those replacing the condyle or forming pedunculated/osseous mass, sometimes combining both types (3,8). Gardner’s syndrome, characterized by colorectal polyps and multiple osteomas, is associated with a high risk of malignant transformation and presents anomalies like retinal pigment hypertrophy, impacted or supernumerary teeth, exostoses, and epidermoid cysts (8).

Clinical presentation

TMJ osteomas typically present with symptoms such as hard palpable swelling, facial asymmetry, and impaired jaw function (3,8) (Table 2). Radiographically, osteomas show homogeneous condylar expansion on the affected side (3,8).

Diagnostic imaging & DD

Panoramic radiograph is an initial diagnostic tool that reveals circumscribed radiopaque masses with a thin sclerotic rim, while, computed tomography (CT) is more reliable for locating the lesion’s nidus, while scintigraphy assesses activity (3,8). DDs include TMD, osteoid osteoma, and osteochondroma (3,8) (Table 3).

Treatment

Surgical excision (condylectomy) is recommended for symptomatic patients, typically in significant facial asymmetry cases while small, asymptomatic lesions can be monitored (3,8). Recurrence has been reported in cases where the lesion was not fully excised. Radiation therapy should be avoided when complete excision is not possible (3,8) (Table 4).

Osteoid osteoma

Osteoid osteoma, a benign solitary bone neoplasm first described by Jaffe in 1935, accounts for 0.5% of hard tissue tumors and is the third most common bone lesion, typically involving long bones (11,12). Its occurrence in TMJ is rare and can present with ambiguous symptoms, often leading to misdiagnosis and delayed treatment (13).

Although the etiology is uncertain, evidence suggests an inflammatory origin with an unusual reparative and healing process and trauma may contribute to its development (12).

Clinical presentation

Nocturnal pain relieved by non-steroidal anti-inflammatory drugs (NSAIDs) is typical of osteoid osteoma (36). Other symptoms like pain, tenderness, and open bite can mimic TMJ dysfunction, leading to misdiagnosis and delayed or excessive treatment (10,13,36) (Table 2).

Diagnostic imaging & DD

Panoramic radiographs may show focal internal calcification with surrounding sclerosis, though small or early-stage lesions are often missed due to limited resolution (9). CT scans are more reliable, revealing a well-defined nidus with surrounding sclerosis, and are considered the most useful modality for accurately visualizing these features (9). Radionuclide bone scintigraphy is a sensitive technique for detecting metabolic activity associated with osteoid osteoma (12).

Osteoid osteoma can be distinguished from other TMJ lesions by the presence of a central nidus and surrounding sclerosis. DD may include benign lesions such as osteochondroma and ossifying fibroma, as well as malignant lesions like osteosarcoma. Integration of clinical evaluation, radiographic imaging, and histopathological findings is critical for confirming the diagnosis of osteoid osteoma and ruling out other possible conditions (10-13,36) (Table 3).

Treatment

Surgical excision is the standard treatment for osteoid osteoma. Minimally invasive techniques, such as CT- or magnetic resonance imaging (MRI)-guided radiofrequency ablation (RFA) and CT-guided laser photocoagulation, have shown comparable efficacy with reduced morbidity, offering less invasive treatment options (12) (Table 4).

Osteoblastoma

Osteoblastoma is a benign bone tumor that typically occurs in the second decade of life, primarily affecting the spine and long bones, with rare involvement of the TMJ and skull bones (approximately 15% of cases) (14).

There are two types of osteoblastoma: conventional benign and aggressive osteoblastic. While radiographically similar, the aggressive subtype is characterized by the presence of large epithelioid osteoblasts on histopathology (14,15).

Clinical presentation

Osteoblastoma typically causes preauricular pain, mimicking TMJ pain, along with impaired jaw function, tenderness to palpation and extraoral swelling (14,15).

Diagnostic imaging & DD

Diagnostic imaging, including radiographs and CT scans, is essential but often insufficient for definitive diagnosis, requiring biopsy and histopathology confirmation. Features include vascularization, osteoblastic hypertrophy, and active new bone formation, with immunohistochemistry aiding in differentiation (14,15).

Osteoblastoma symptoms overlap with TMD and other lesions such as ossifying fibroma, osteoid osteoma, giant cell lesions, aneurysmal bone cyst, and low-grade osteosarcoma (14,15) (Table 3).

Treatment options

Gross total resection is the standard treatment, aiming for complete removal. If the tumor is located near critical structures, curettage might be considered (14,15). Carbon ion radiotherapy has shown promising outcomes in some cases but must be used cautiously due to the potential risks of malignant transformation (14,15) (Table 4).

Chondroma/synovial chondromatosis

Chondromas are benign cartilaginous neoplasms typically located proximal to articular capsules and tendons within the skeleton (16). Rare extraskeletal or soft-tissue chondromas occur without attachment to bone or periosteum (17). TMJ chondromas, accounting for only 3% of all cases, are classified as synovial chondromatosis (17).

Clinical presentation

Synovial chondromatosis of the TMJ is rare, painless, and slow-growing, often leading to diagnostic challenges (16,17). Clinical symptoms may include pain, limited mouth opening, swelling and sometimes crepitus or clicking, which may be misdiagnosed as TMD or parotid gland lesions (Table 2) (16,17).

Diagnostic imaging and DD

CT and MRI typically reveal a well-demarcated, partially calcified mass with adjacent bone remodeling and atrophy (16,17). MRI shows hypo- to isointense signals on T1, hyperintense signals on T2 with contrast enhancement (16,17). Fine-needle aspiration (FNA) cytology is a useful, less-invasive tool for chondromas (16,17) (Table 3).

Histologically, synovial chondromatosis features cartilage nodules, sometimes with atypical features like hypercellularity and increased mitoses (Table 3). Milgram’s classification (16) stages synovial chondromatosis based on histological progression:

• Stage I: chondrogenesis without loose bodies.
• Stage II: active chondrogenesis with loose bodies.
• Stage III: disappearance of chondrogenesis with visible loose bodies.

DD includes TMD, parotid gland tumors, extraskeletal chondroma, chondromyxoid fibroma, chondroblastoma, chondrosarcoma, osteochondroma, pleomorphic adenoma, and synovial cysts (16,17).

The main pathological feature is the presence of cartilaginous nodules adjacent to the synovium, often connected by a stalk, with central areas of loose bodies that may undergo necrosis and calcification (16,17). Transforming growth factor β3 (TGF-β3) promotes cartilage formation and angiogenesis in the synovium and loose bodies, while Ki-67 expression suggests active cell proliferation in the synovium (16,17).

Treatment options

Complete surgical resection, including the fibrous capsule, is the primary treatment. Arthroscopy is a less invasive option for bodies smaller than 3 mm in a single compartment. Intraoperative nerve monitoring is crucial for preserving facial nerve branches to the parotid glands. Long-term follow-up is recommended due to a 10–15% recurrence rate. Combining arthroscopy with open surgery allows thorough lesion removal with minimal osteotomy (16,17) (Table 4).

Osteochondroma

Osteochondromas are slow-growing benign bone tumors originating from the bone cortex, rarely affecting the craniofacial region, particularly the mandibular condyle. They account for approximately 35–50% of all benign tumors and 8–15% of all primary bone tumors, but only 0.6% occur in the craniofacial region (18,19).

Clinical presentation

TMJ osteochondromas present with unilateral condylar enlargement, dentofacial asymmetry (e.g., ipsilateral chin deviation and occlusion changes), preauricular pain resembling neuralgic symptoms, joint sounds and non-tender, bony swelling (18-21). These signs suggest TMJ dysfunction, warranting further diagnostics to rule out osteochondroma (Table 2).

Diagnostic imaging and DD

Osteochondromas radiographically appear as sclerotic exophytic masses. Panoramic radiographs show shortening of the condylar neck, along with flattening and widening of the condylar head on the affected side. CT scans provide detail on soft tissue involvement, while MRI better visualizes surrounding structures, including nerves and vessels (Table 3) (19,20).

Histologically, osteochondromas are well-circumscribed masses of bone with a cartilaginous cap containing proliferating chondrocytes, resembling endochondral ossification, suggesting an origin from the mandibular condyle (20) (Table 3).

DDs include unilateral condylar hyperplasia and osteoma. Radiographically, condylar hyperplasia appears as a uniformly enlarged but regularly shaped condyle (19).

Treatment options

Management of osteochondromas focuses on both functional and aesthetic restoration, and involves complete resection for symptom relief and esthetic restoration. Reconstruction methods include autogenous costochondral grafts and alloplastic total joint replacements, with advanced techniques like virtual surgical planning and three-dimensional (3D) printing ensuring precise anatomical reconstruction (Table 4) (18,21).

Chondroblastoma

Chondroblastomas account for 1% of all benign bone tumors, primarily occurring in long bones, and are extremely rare in the craniofacial region, where they may involve the squamous portion of the TMJ and the temporal (22-24). Approximately 70% of these tumors occur in long bones, while only 7% of them are found in the craniofacial region.

Chondroblastomas in long bones are typically reported during adolescence, whereas those in the craniofacial region usually manifest between the ages of 30 and 40 years, with a male-to-female ratio of 2:1 (22-25).

Clinical presentation

TMJ chondroblastomas are typically destructive and involve adjacent structures, causing symptoms like otalgia, tinnitus, hearing loss, paresthesia, swelling and pain. TMJ dysfunction, such as occlusal changes, joint sounds (especially crepitus), and deviation of mouth opening, has also been reported (22-25) (Table 2).

Diagnostic imaging and DD

Radiologically, chondroblastomas appear as osteolytic lesions with well-defined sclerotic margins. CT scans reveal irregularly lobulated expansile masses eroding adjacent structures, while MRI provides detailed soft tissue imaging, essential for assessing dural or brain tissue involvement (Table 3) (22-25). A multidisciplinary approach is required to evaluate the patient and accurately assess the extent of the lesion.

Histologically, the lesion consists of proliferating chondroblasts with mildly pleomorphic, ovoid to round nuclei of varying sizes (23). The cytoplasm is focally clear and eosinophilic. Interspersed osteoclast-type giant cells and a pink chondroid matrix with characteristic “chicken-wire” calcifications are typical features.

DD includes chondrosarcoma, chondromyxoid fibroma, synovial sarcoma, synovial chondromatosis, aneurysmal bone cyst, osteosarcoma, and malignant fibrohistiocytoma (23). Non-invasive lesions like giant cell tumor, enchondroma, eosinophilic granuloma, or aneurysmal bone cysts should also be considered suggesting precise histopathologic analysis for definitive diagnosis (22-25).

Treatment options

Surgical excision is the preferred treatment, with preauricular approach offering optimal access and cosmetic benefits. En bloc excision, without radiotherapy, preserves anatomical structures and TMJ functionality (22-25). Long-term follow-up is essential to monitor for rare recurrence (22-25) (Table 4).

Tenosynovial giant cell tumor (TGCT)

TSGCT, also known as pigmented villonodular synovitis (PVNS) is a benign, proliferative lesion originating from the synovium of joints, tendon sheaths, and bursae (26-30). It involves abnormal fibroblast and histiocyte growth, with up to 50% of cases involving bone destruction, particularly in the knee, and recurrence rates ranging from 18% to 50% (28). The etiology remains, potentially linked to chronic inflammation or a neoplastic process (28). TGCT can be intra- or extra-articular, with localized or diffuse growth patterns (26-30). TMJ involvement is rare, and challenging to clarify due to the joint’s complexity (28). The average age of onset is 45 years, with equal male-to-female ratio (28).

Clinical presentation

TGCT often mimics parotid neoplasm or other TMJ tumors, presenting with a preauricular mass, limited mandibular motion, ear fullness, hearing loss, headaches, and tinnitus (26-30). Additional symptoms may include altered sensation, otitis media, dizziness, trismus, and facial numbness, resembling TMJ dysfunction (26-30) (Table 2).

Diagnostic imaging and DD

TGCT’s overlapping symptoms make diagnosis challenging (26-30). Enhanced-contrast MRI is valuable for assessing the lesion’s extent, showing heterogeneous signal intensity due to hemosiderin deposition and the “blooming effect” (26-30). CT scan shows bone destruction, ossification, and cystic changes in the TMJ and surrounding area (26-30) (Table 3).

Histopathology, TGCT is characterized by hemosiderin deposition, villous masses, synovial folds, and multinucleated giant cells, with chondroid metaplasia aiding differentiation from other tumors (26-30) (Table 3).

DD include giant cell reparative granuloma (GCRG), chondroblastoma, giant cell tumor, aneurysmal bone cyst (ABC), and brown tumor of hyperparathyroidism, as these conditions share overlapping features with TGCT (26-30). TGCT of the TMJ can also be misdiagnosed as a parotid neoplasm, ear disease, or other TMJ tumor due to its nonspecific symptoms (26-30).

Treatment and prognosis

Complete surgical resection is the standard treatment, though complications such as facial paralysis, hearing loss, and limited jaw movement may occur (26-30). Computer-assisted surgical navigation helps preserve vital structures and determine accurate margins, especially with skull base or carotid artery involvement (26-30). Adjunctive Low-dose radiotherapy can help manage residual or recurrent tumors (27,28). Arthroscopic surgery is also effective for intra-articular TMJ lesions (26-30). The Ki-67 index and MMP-9/13 expression (27) are potential predictors of recurrence, with a 5-year recurrence rate of approximately 29% (29) (Table 4).

Synovial hemangiomas

Synovial hemangiomas are rare benign vascular tumors originating from the synovial lining of joints, most commonly affecting the knee and rarely involving the TMJ (31,32). Synovial hemangiomas primarily affects young adults and children, with a higher incidence in females (33). Bennett and Cobey classified synovial hemangiomas into localized and diffuse types (32). The localized form is a well-circumscribed, pedunculated mass causing joint locking, while the diffuse type is infiltrative, presenting with joint pain, swelling, hemarthrosis, and occasionally increased limb length (32). The pathogenesis in the TMJ is unclear, with proposed mechanisms including post-traumatic degeneration, herniation of the articular disc, synovial tissue displacement during embryogenesis, or activation of a congenital hemangioma (32).

Clinical presentation

Symptoms of synovial hemangiomas can range from asymptomatic incidental findings to localized pain, TMD, and myofascial pain (31,32). TMJ involvement can cause progressive pain, limited jaw motion, and soft, tender preauricular swelling (31,32) (Table 2).

Diagnostic imaging and DD

Radiographs including CT and MRI may show phleboliths. MRI is particularly useful, showing characteristic T2 hypointensity due to hemosiderin and assessing lesion extent. CT can help evaluate bony changes (31,32). Tumor aspiration, which leads to temporary lesion size reduction, is another diagnostic aid (31,32) (Table 3).

Histopathology typically shows dense connective tissue, blood material, large blood-filled vessels, and synovial folds with hemosiderin pigmentation. DD includes synovial chondromatosis, giant cell lesions, and synovial or ganglion cysts (31,32).

Treatment and prognosis

Complete surgical excision is the preferred treatment and has been reported to improve clinical symptoms. Recurrence is rare, with few reported cases following excision (32,33).

Intraosseous lipoma

Intraosseous lipomas are exceedingly rare benign tumors composed predominantly of mature adipose tissue, accounting for 0.1% of all bone tumors (33). Often discovered incidentally during radiographic examinations, intraosseous lipomas typically affect adults, with an average reported age of 48 (33). About 25% of patients with intraosseous lipoma are asymptomatic and are diagnosed incidentally (33).

Clinical presentation

Although often asymptomatic, intraosseous lipomas can manifest with localized pain, swelling, or sensory disturbances depending on their size and anatomical location within the mandible (33) (Table 2).

Diagnostic imaging and DD

Intraosseous lipomas appear as well-defined, uni- or multilocular radiolucent lesions on X-rays, often with a honeycomb or soap-bubble appearance (33). MRI shows hyperintense signals on both T1- and T2-weighted sequences due to adipose tissue (33) (Table 3).

Histologically, ILs consist of mature adipocytes arranged in lobules, without significant nuclear atypia or mitotic activity (33). The absence of bone trabeculae or calcifications helps differentiate ILs from other lesions. Milgram’s staging system (stages 1–3) assesses prognosis and malignancy risk (33). Differentiating ILs from other mandibular radiolucent lesions, such as cysts and giant cell granulomas, requires careful radiographic and histopathological evaluation (33).

Treatment and prognosis

Surgical curettage or resection is the preferred treatment, with excellent prognosis and rare recurrence. Malignant transformation to liposarcoma is exceedingly rare (33) (Table 4).

Langerhans cell histiocytosis (LCH)

LCH is a rare disorder involving clonal proliferation of abnormal Langerhans cells, often affecting children (~5 cases/million annually) and occasionally adults. Around 10% of cases involve the oral/maxillofacial region, with mandibular condyle involvement being particularly rare (34). The exact cause is unclear but may involve abnormal immune responses, infections, or neoplastic processes (34). Abnormal Langerhans cells can accumulate in tissues, leading to localized bone lesions, multisystem involvement, or disseminated disease (34).

Clinical presentation

Common symptoms of LCH include bone pain, swelling, localized tenderness, and functional impairment, particularly if the lesion affects weight-bearing bones or joints (34). Oral manifestations can mimic periodontal disease or TMD, with mucosal ulceration, tooth mobility, or swelling (34) (Table 2).

Diagnostic imaging and DD

Radiographs may show varying patterns of bone destruction, outlining the extent of involvement. CT scans provide detailed images of bone destruction and surrounding structures, aiding surgical planning, while MRI is essential for assessing soft tissue and marrow infiltration (34,35) (Table 3).

Tissue biopsy, including FNA, can confirm the presence of Langerhans cells, characterized by convoluted nuclei and prominent eosinophils (34,35). Immunohistochemical staining for markers like CD1a and S-100 protein is crucial for diagnosis (34,35). Blood and urine tests help assess systemic involvement and monitor disease activity, with elevated alkaline phosphatase or inflammatory markers indicating active disease (34). Genetic testing, such as BRAF-V600E mutations (34,35), offers additional diagnostic and prognostic insights, particularly for aggressive or resistant cases.

Treatment and prognosis

Treatment of LCH depends on disease extent and organ involvement, requiring a multidisciplinary team of oncologists, radiologists, and surgeons for optimal outcomes (34). Surgical curettage is effective for solitary bone lesions, while extensive or refractory cases may require complete surgical resection (34).

Patients with solitary bone or skin lesions (eosinophilic granuloma) generally have an excellent prognosis with appropriate treatment, though outcomes vary in multiorgan involvement (34). Many cases resolve spontaneously or with minimal intervention. Regular follow-ups and imaging are essential to monitor disease activity, detect recurrence, and manage complications (34,35).

Malingnant tumors

Osteosarcoma

Osteosarcoma is a rare and aggressive malignant bone tumor caused by osteoblast proliferation accounts for approximately 20% of all primary bone tumors, making it the most common primary malignant bone tumor (37). Osteosarcoma primarily affects adolescents and young adults, with most cases occurring around puberty rather than older adults. While it predominantly arises in the long bones, 6–8% of cases involve the jaw, predominantly affecting the body and angle of the mandible (37).

Clinical presentation

Patients reports of persistent, dull, achy pain in the TMJ region, often radiating to the face and ear that can get aggravated by jaw function like chewing (37). Common symptoms include swelling, facial asymmetry, limited jaw motion, altered bite patterns, tooth loosening, and nerve-related issues such as numbness or muscle weakness. Advanced cases may present systemic symptoms like fatigue and weight loss (37) (Table 5).

Diagnostic imaging and DD

Panoramic radiographs can detect bony changes, such as erosions or osteosclerosis, and assess joint spaces (37). Cone beam CT provides detailed 3D imaging of the TMJ, showing bony morphology, condyle position, joint space, and osteophytes or defects (37). MRI offers excellent soft tissue contrast, useful for evaluating the TMJ disc, synovium, and surrounding tissues, as well as detecting effusion, disc displacement, and structural changes (37). Histologically, osteoid cells and a predominance of chondroid matrix are present, with Immunohistochemistry reveals S-100 and CD99 markers (38,39) (Table 6).

Treatment and prognosis

Complete surgical resection of the tumor is the choice of treatment, aiming to preserve healthy tissue and TMJ function (37,39). Chemotherapy is often used as adjunctive therapy, particularly when surgery alone is insufficient. Boron neutron capture therapy (BNCT), a type of radiation therapy, targets tumor cells while sparing healthy tissue (37,39). The prognosis depends on tumor size, location, metastasis, and response to treatment. Younger patients with smaller tumors and complete surgical resection have a 5-year survival rate of 60–70% (37). Regular follow-up, including imaging, is necessary to monitor for recurrence or metastasis (37). Long-term management may involve rehabilitation and supportive care for treatment-related complications (37) (Table 7).

Chondrosarcoma

Chondrosarcoma is a rare malignant bone tumor characterized by the production of cartilaginous matrix by tumor cells (40,41). It is the second most common primary malignant bone tumor, typically affecting adults in their 40s to 60s, with a slight female predominance and a mean age of 46.7. Chondrosarcomas primarily arise in long bones, with only 1–12% of cases involving the TMJ (40).

Chondrosarcoma is classified into three grades based on histological features: Grade I, Grade II, and Grade III (40). Prognosis varies significantly by grade, with 5-year survival rates of 90%, 81%, and 43%, respectively, and 10-year survival rates of 83%, 64%, and 29% (40). Recurrence, rather than metastasis, is often the leading cause of death.

Clinical presentation

Patients typically report persistent, progressive jaw pain, ranging from dull to intense, depending on tumor size and grade (40,41). Swelling, facial asymmetry, and mandibular displacement are common, with tumor growth potentially impairing mandibular movement, causing trismus and limited mouth opening (40,41). Nearby structures, especially nerves, may be affected, leading to neurological symptoms such as numbness, tingling, or facial weakness (40,41) (Table 5).

Diagnostic imaging and DD

MRI and CT scans are crucial for assessing bony destruction, tumor spread, and DD (40). A PET scan can confirm the absence of distant metastasis pre-operatively (40,41) (Table 6).

Histopathological and immunohistochemical analysis of markers like S-100, D2-40, CD68, and Ki-67 is essential for accurate diagnosis (40). Biopsies, including incisional, core needle, or FNA, are commonly used, with the tumor’s location and accessibility as key factors (40). DD includes other primary and secondary bone tumors, as well as benign conditions like osteosarcoma, Ewing sarcoma, benign cartilaginous tumors, and TMD (40).

Treatment and prognosis

Surgical excision of chondrosarcoma is to attain clear margins and is challenging due to facial nerve proximity and a conservative approach is recommended for post-operative complications (40). Reconstruction strategies, such as vascularized free flaps (e.g., fibular free flap or costal bone grafts) or local flaps (e.g., temporalis muscle flap), depend on defect size and location. Post-operative physical therapy is recommended for improved outcomes (40). Autogenous bone or vascularized flaps during joint reconstruction may be associated with joint ankylosis (40) (Table 7).

Post-operative management includes periodic and long-term follow-ups with imaging studies such as enhanced CT and chest X-rays to monitor for local recurrence or metastasis (40). Post-operative radiation therapy may be considered based on the surgical margins and tumor grade (40).

Synovial sarcoma

Synovial sarcoma is a malignant mesenchymal neoplasm that predominantly affects deep soft tissues surrounding joints and tendons rather than the synovium itself (42,43). It originates from pluripotent mesenchymal cells and accounts for approximately 5–10% of all soft tissue sarcomas (44). It typically occurs in the lower extremities, with head and neck involvement being rare (3–10% of cases), including the TMJ. Most patients are 17–67 years, with a mean age of 35 years (44).

Clinical presentation

In the TMJ region, synovial sarcoma often presents as a painful, mobile mass located in the preauricular area (42-44). The swelling is reported to be associated with localized pain and tenderness to palpation, although it is also reported to be asymptomatic or present with nonspecific symptoms (42-44). Patients may experience limited mouth opening, dysphagia, or hoarseness, depending on the size and location of the tumor (42-44) (Table 5).

Diagnostic imaging and DD

CT and MRI are the standard modalities for assessing tumor size, location, and involvement of adjacent structures, with CT particularly useful for detecting bone destruction (42-44). On imaging, synovial sarcoma typically appears as a well-defined, multilocular mass with heterogeneous enhancement and irregular peripheral calcifications, often showing significant expansion (42-44).

Histologically, synovial sarcoma can be classified into biphasic, monophasic spindle cell, monophasic epithelial, and poorly differentiated types (42-44). The biphasic type, with both epithelial and spindle cell components, is more recognizable, while the monophasic spindle cell type can be more difficult to diagnose (42-44). Immunohistochemical staining, with markers like epithelial membrane antigen, CK7, CK19, vimentin, CD99, and BCL-2, aids in diagnosis (42-44) (Table 6).

Treatment and prognosis

The management of synovial sarcoma typically involves surgery, radiation therapy, and chemotherapy. Complete surgical excision with clear margins is crucial for improving outcomes. Adjuvant radiation therapy has been shown to reduce recurrence rates in head and neck synovial sarcoma (44). However, there are limited data on the impact of chemotherapy regimens, such as doxorubicin and ifosfamide, on survival rates (44). The prognosis for head and neck synovial sarcoma is poor, with a 5-year survival rate of 66% and a disease-specific survival rate of 71% (44). Distant metastases, particularly to the lungs, are common and associated with a poor prognosis (44) (Table 7).

Ewing sarcoma

Ewing sarcoma is a malignant small, round blue cell tumor that primarily affects bone and soft tissues, with a higher incidence in adolescents and young adults (45). It is a rare and aggressive tumor, characterized by its distinct histological features and genetic mutations (45). Ewing sarcoma occurrence in the TMJ is relatively less frequent compared to the mandible and maxilla (45). Most cases occur in adolescents and young adults, with a peak incidence between ages 10 and 20 years (45).

Clinical presentation

The clinical presentation of Ewing sarcoma often includes localized pain, swelling, and occasionally systemic symptoms such as fever and weight loss (45). Early signs, including facial edema and pain, may mimic dental issues like impacted third molars. Key symptoms include progressive pain, swelling, trismus, and a palpable, non-tender preauricular mass (45) (Table 5).

Diagnostic imaging and DD

CT imaging typically shows an expansile bony lesion of the condylar process with spiculated periosteal bone formation, suggesting malignancy (45). MRI provides detailed imaging of soft tissue involvement, aiding in surgical planning (45). A radionuclide bone scan can detect metastases and assess bone involvement. Microscopically, Ewing sarcoma is characterized by small, round, hyperchromatic cells with scant cytoplasm and indistinct borders (45). Periodic acid-Schiff staining is positive for cytoplasmic glycogen (45). Tumor cells are typically positive for FLI1 and CD99, while negative for leukocyte common antigen (LCA) (45). Genetic testing often identifies the EWS-FLI1 fusion gene, a hallmark of Ewing sarcoma (45) (Table 6).

Treatment and prognosis

A multi-agent chemotherapy protocol, including vincristine, cyclophosphamide, mesna, doxorubicin, ifosfamide, and etoposide, is used to reduce tumor size and control metastasis prior to surgery (45). Wide surgical resection with clear margins is critical, though it may result in significant disfigurement, necessitating functional and aesthetic reconstruction by a multidisciplinary team (45). Combined chemotherapy and surgical approaches improve survival rates. The prognosis depends on tumor size, location, metastasis, and chemotherapy response, with regular follow-ups required to monitor recurrence (45).

Pain management in benign and malignant neoplasms of the TMJ

Multimodal pain management is essential for TMJ neoplasms, focusing on early diagnosis and a combination of pharmacological and non-pharmacological approaches. Post-surgical pain is commonly managed with NSAIDs, opioids, and local anesthetics (46,47). In more severe cases, targeted nerve ablation, corticosteroid injections, nerve blocks, and biologic therapies [e.g., anti-tumor necrosis factor (TNF)-alpha] have shown promise. Additionally, transcutaneous electrical nerve stimulation (TENS) can complement pharmacological treatments to enhance pain relief and improve patient outcomes (46,47). The increasing use of patient-reported outcome measures (PROMs) (48) for assessing quality of life highlights the need for further research to optimize their application in patient management.

Conclusions

Evidence reveal that both benign and malignant tumors of the TMJ present a complex landscape with significant implications for diagnosis, treatment, and patient outcomes. Tumors of the TMJ, whether benign or malignant, often mimic TMD clinical presentation, leading to delayed diagnosis and, consequently, postponement of appropriate treatment. Benign tumors, such as synovial chondromatosis, osteochondromas, and osteomas, generally have a favorable prognosis with timely surgical intervention and regular follow-up. In contrast, malignant tumors, including Ewing sarcoma and osteosarcoma, require a more complex and aggressive approach, often involving a combination of chemotherapy, surgical resection, and multidisciplinary care.

Accurate diagnosis, guided by advanced imaging techniques and histopathological analysis, is crucial for effective treatment planning. Ongoing research and innovations in diagnostic methodologies and treatment modalities continue to improve the management and outcomes of patients with TMJ tumors. Despite advances in diagnostic imaging and treatment strategies, the rarity and diversity of TMJ tumors underscore the need for further research to improve early detection, refine therapeutic protocols, and enhance prognostic accuracy. Future research should prioritize the development of standardized treatment guidelines and pain management strategies addressing the unique challenges posed by these neoplasms, ultimately aiming to improve patient outcomes and quality of life.

Acknowledgments

None.

Footnote

Provenance and Peer Review: This article was commissioned by the Guest Editors (Mythili Kalladka & Ming Xia) for the series “Current status and latest research progress in the pain management of temporomandibular disorders (TMDs)” published in Journal of Oral and Maxillofacial Anesthesia. The article has undergone external peer review.

Reporting Checklist: The authors have completed the Narrative Review reporting checklist. Available at https://joma.amegroups.com/article/view/10.21037/joma-24-25/rc

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Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://joma.amegroups.com/article/view/10.21037/joma-24-25/coif). The series “Current Status and Latest Research Progress in the Pain Management of Temporomandibular Disorders (TMDs)” was commissioned by the editorial office without any funding or sponsorship. The authors have no other conflicts of interest to declare.

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