Chondroid Tenosynovial Giant Cell Tumor of the Temporomandibular Joint: A Case Report

We present a rare case of a chondroid tenosynovial giant cell tumor (TGCT) involving the temporomandibular joint (TMJ) in a 46-year-old man with an asymptomatic but progressively enlarging lesion centered within the zygomatic air cell tract superior to the TMJ. A computed tomography (CT) scan performed for sinusitis symptoms revealed an expansile lesion near the zygomatic air cell tract above the TMJ, which had grown undetected over 16 years, eroding the squamous temporal bone and extending to the middle fossa dura. Magnetic resonance imaging (MRI) showed T1- and T2-hypointense, heterogeneously enhancing nodules in the TMJ, with susceptibility artifacts on diffusion-weighted sequences indicating hemosiderin staining, suggestive of a chondroid TGCT originating from the synovial disc in the glenoid fossa. A preauricular infratemporal approach enabled complete resection of the tumor, synovial disc, and adjacent affected bone. The mandibular condyle was unaffected and preserved. Reconstruction was performed using a pedicled temporoparietal fascia flap. One-year follow-up MRI showed no recurrence, and the patient experienced successful mastication without pain. This case illustrates the diagnosis and surgical management of chondroid TGCT of the TMJ, emphasizing its potential for slow, asymptomatic growth and its CT appearance of a primary temporal bone lesion. The characteristic MRI features assist in diagnosis, and chondroid TGCT should be considered when evaluating erosive lesions near the glenoid fossa.