Diffuse-Type Tenosynovial Giant Cell Tumor Arising in the Temporomandibular Joint Extending to the External Auditory Canal: A Case Report and Literature Review

A 74-year-old Japanese woman with a 1-year history of right preauricular pain and a 2-month history of bleeding from the right ear was admitted to our department. Tumor was observed in the anterior wall in the right external auditory canal. Bony swelling of the right preauricular area was palpated. Computed tomography revealed an ill-defined, osteogenic tumor around the mandibular condyle with a destructive bony lesion involving the temporal bone. Magnetic resonance imaging revealed a 2.0 × 1.5 × 1.3-cm solid tumor around the mandibular condyle, exhibiting a low-intensity signal on T1-weighted imaging and an isointense central area surrounded by low-signal intensity on T2-weighted imaging. Histological examination of biopsy specimens revealed diffuse-type tenosynovial giant cell tumor (D-TGCT). After the feeding arteries for the tumor were embolized, the patient underwent surgery with combined temporal craniotomy and mandibular condylectomy. The soft and cystic tumor with calcification located in the extradural space was totally resected along with the mandibular condyle. No facial paralysis or recurrence was evident as of 6 months postoperatively. To date, only 23 cases of D-TGCT arising in the temporomandibular joint (TMJ) with ear involvement have been reported since 2011. We report successful resection of a rare case of D-TGCT arising in the TMJ.