Uncommon tumors of temporomandibular joint: An institutional experience and review

First report on parotid tissue choristomas within and adjacent to TMJ ligaments

OBJECTIVE

To report the first examples of ectopic salivary glands of TMJ ligaments & capsules.

METHODS AND MATERIALS

Nine subjects with chronic TMJ disorders were found incidentally to have ectopic salivary glands (choristomas) within or near damaged TMJ ligaments and capsules. Clinicopathologic characteristics of 12 TMJs are summarized.

RESULTS

The 9 subjects were ages 22-64 years (average = 43.0); 6 were female. Microscopic examination revealed major, almost complete ligament replacement by dense, avascular fibrous scar tissue in all but 1 sample. Chronic inflammatory cells were present in the stroma of 3 samples. A total of 33 lobular, independent salivary structures of variable sizes were embedded in or near ligaments and/or capsules. Half were multiple in the same joint; 13 were bilaterally located in the joints of a single subject, with 8 small glandular lobules in one TMJ. All glands consisted of histologically normal serous acini except 1 which showed a focal lobule of mucus acini and another comprised only of mucus acini. Serial sections showed no connection to parotid glands. Some choristomas showed the aging phenomena of fatty infiltrates (n = 7) and oncocytosis (n = 7). Additionally, 3 of the 12 TMJ samples contained preauricular lymph nodes, with 3 nodes in 1 joint and bilateral involvement in 1 subject. Of the 5 identified nodes, all but one was hyperplastic, with nonspecific inflammatory histiocytosis.

CONCLUSIONS

We report, for the first time, independent salivary gland choristomas (n = 33) within the soft tissues of the TMJ (n = 12), with one joint containing 8 such choristomas. All consisted of normal serous tissue except one, a mucus gland. Additionally, a fourth of TMJ surgical samples contained hyperplastic preauricular lymph nodes.

Tenosynovial giant cell tumor: case report and molecular investigation

Tenosynovial giant cell tumor is a benign neoplasm arising from the synovium of joints, including the temporomandibular joint (TMJ). Despite its benign nature, these tumors may exhibit aggressive behavior. A 57-year-old woman with a swollen, hardened area in the left TMJ was referred to the university´s clinic. The diagnosis of tenosynovial giant cell tumor was made based on the presence of hyperplastic synovial lining containing mononuclear and giant cells, hemorrhagic areas, hemosiderin deposits, and calcification foci in the biopsy. A low condylectomy was performed, and histopathologic analysis of the surgical piece upheld the diagnosis. Due to histopathologic resemblance with other giant cell-rich lesions (giant cell granuloma of the jaws, brown tumor of hyperparathyroidism, and non-ossifying fibroma) for which signature mutations are known, mutational analysis of KRAS, FGFR1, and TRPV4 genes was conducted. The results revealed wild-type sequences for all the mutations tested, thereby supporting the diagnosis of tenosynovial giant cell tumor.

Reconstruction of the temporomandibular joint using a vascularized medial femoral condyle osteocartilaginous flap: an experimental investigation in miniature pigs

BACKGROUND

Reconstruction of the temporomandibular joint (TMJ) is a significant challenge in maxillofacial surgery. A vascularized medial femoral condyle (MFC) osteocartilaginous flap is a good choice for TMJ reconstruction. In this study, we evaluated the radiographic and histological changes of MFC after TMJ reconstruction.

METHODS

A ramus-condyle unit (RCU) defect was created unilaterally in five adult male Bama miniature pigs. The ipsilateral vascularized MFC osteocartilaginous flap was used to reconstruct the TMJ, and the non-operative sides served as controls. Multislice spiral computed tomography (CT) was performed preoperatively, immediately postoperatively, and at two weeks, three months, and six months postoperatively. Three animals were euthanized at 6 months postoperatively. Their reconstructed condyles, natural condyles and the MFCs on the opposite side were collected and subjected to µCT and histological evaluation.

RESULTS

In the miniature pigs, the vascularized MFC osteocartilaginous flap was fused to the mandible, thus restoring the structure and function of the RCU. The postoperative radiographic changes and histological results showed that the reconstructed condyle was remodeled toward the natural condyle, forming a similar structure, which was significantly different from the MFC.

CONCLUSIONS

In miniature pigs, the RCU can be successfully reconstructed by vascularized osteocartilaginous MFC flap. The reconstructed condyle had almost the same appearance and histological characteristics as the natural condyle.

Computed tomography and magnetic resonance imaging characteristics of giant cell tumors in the temporomandibular joint complex

Purpose

This study aimed to investigate the computed tomography and magnetic resonance imaging features of giant cell tumors in the temporomandibular joint region to facilitate accurate diagnoses.

Materials and Methods

From October 2007 to June 2020, 6 patients (2 men and 4 women) at Yonsei University Dental Hospital had histopathologically proven giant cell tumors in the temporomandibular joint. Their computed tomography and magnetic resonance imaging findings were reviewed retrospectively, and the cases were classified into 3 types based on the tumor center and growth pattern observed on the radiologic findings.

Results

The age of the 6 patients ranged from 25 to 53 years. Trismus was found in 5 of the 6 cases. One case recurred. The mean size of the tumors, defined based on their greatest diameter, was 32 mm (range, 15–41 mm). The characteristic features of all cases were a heterogeneously-enhancing tumorous mass with a lobulated margin on computed tomographic images and internal multiplicity of signal intensity on T2-weighted magnetic resonance images. According to the site of origin, 3 tumors were bone-centered, 2 were soft tissue-centered, and 1 was peri-articular.

Conclusion

Computed tomography and magnetic resonance imaging yielded a tripartite classification of giant cell tumors of the temporomandibular joint according to their location on imaging. This study could help clinicians in the differential diagnosis of giant cell tumors and assist in proper treatment planning for tumorous diseases of the temporomandibular joint.

Malignant tumours of temporomandibular joint

Background

Malignant tumours of the temporomandibular joint (MTTMJ) are extremely rare. Studies describing its unique epidemiology, clinicopathological features, treatment and prognosis comprehensively are limited. To address these issues, current investigation was performed.

Methods

A retrospective research was carried out by using population-based data from the Surveillance, Epidemiology, and End Results database (1973–2016).

Results

Data for a total of 734 patients, including 376 men and 358 women, was found. The median age was 47 years. The 5-year and 10-year disease specific survival (DSS) rates were 69.2 and 63.6%, respectively. Significant differences in DSS were found according to age, race, tumour type, AJCC/TNM stage, surgery, radiotherapy, chemotherapy and different treatment modalities (P < 0.05). In the multivariate survival analysis, age > 44 years and AJCC stage III and IV were associated with poor DSS.

Conclusion

MTTMJ was mostly found in white people with a median age of 47 years without any sex predominance. Patient’s age and AJCC stage was independent predictor of DSS.