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Updated: Sep 25, 2026
Systematic Assessment of Mammalian Skull Specimens for Dental and Temporomandibular Joint Pathology
Published on: August 22, 2022
Incidentally found and unexpected tumors discovered by MRI examination for temporomandibular joint arthrosis
Yoshinobu Yanagi1, Jun-ichi Asaumi, Yuu Maki
1Department of Oral and Maxillofacial Radiology, Field of Tumor Biology, Graduate School of Medicine and Dentistry, Okayama University, 2-5-1, Shikata-cho, Okayama 700-8525, Japan.
Abstract:
We examined the frequency of incidentally found or unexpected tumors discovered at the time of magnetic resonance imaging (MRI) examinations in the temporomandibular joint (TMJ) region for patients with suspicion of TMJ arthrosis. Five MR images (T1-weighted transverse scout image and proton density and T2-weighted oblique sagittal images at the open and closed mouth) were acquired. In 2776 MRI examinations of TMJ arthrosis, two tumors were discovered. They consisted of an adenoid cystic carcinoma in the deep portion of the parotid gland, and a malignant tumor extending from the infratemporal fossa to the parapharyngeal space. The rate of incidentally founded or unexpected tumors in TMJ examinations was low (0.072%), but the two tumors found were malignant tumors, and therefore, scout image should be carefully examined, not only used for positing the slice.
Insights
Incidental tumors are rarely found during temporomandibular joint (TMJ) MRIs for arthrosis, but when detected, they are often malignant. Careful examination of scout images is crucial for early cancer detection in these unexpected findings.
Area of Science:
- Radiology
- Oncology
- Otorhinolaryngology
Background:
- Temporomandibular joint (TMJ) arthrosis is commonly evaluated using magnetic resonance imaging (MRI).
- Incidental findings during diagnostic imaging can sometimes lead to the discovery of unexpected pathologies.
- The diagnostic yield of TMJ MRI for non-arthrosis related pathologies, particularly tumors, is not well-established.
Observation:
- A retrospective review of 2776 TMJ MRI examinations performed for suspected arthrosis was conducted.
- Two unexpected tumors were identified in patients undergoing TMJ MRI.
- The tumors discovered were an adenoid cystic carcinoma and a malignant tumor extending from the infratemporal fossa.
Findings:
- The incidence of incidentally discovered tumors during TMJ MRI for arthrosis was found to be low at 0.072%.
- Both incidentally discovered tumors in this study were malignant, highlighting a significant clinical concern.
- The identified malignancies included an adenoid cystic carcinoma of the parotid gland and a tumor with extensive spread.
Implications:
- Despite the low frequency, the high malignancy rate of incidental tumors in TMJ MRI underscores the importance of thorough image review.
- Radiologists should carefully examine scout images, not solely for slice positioning, to detect potentially life-threatening incidental findings.
- This study suggests that TMJ MRI may have a role in the incidental detection of head and neck malignancies, warranting careful interpretation.
