Synovial chondromatosis of the right side temporomandibular joint extending to the middle cranial fossa: A case report with 7-year postoperative follow up and expression of a biomarker of cell proliferative activity

• Neoplastic disease of the TMJ is a rare condition.
• We report a case of Synovial chondromatosis of the right side temporomandibular joint extending to the middle cranial fossa.
• We evaluated the cell proliferative activity by immunohistochemical analysis.
• Then, we confirmed the growth activity of the lesion and it was thought to be a cause of the tumor expansion.
• This is a case report with 7-year postoperative follow up without reoccurrence.

IntroductionSynovial chondromatosis of the temporomandibular joint (TMJ) with cranial extension is rare. Here, we report 7-year follow-up of a case with immunohistochemical examination of cell proliferative activity.Presentation of caseThe patient was a 72-year-old man. Severe bone resorption of the glenoid fossa was apparent on CT images. Pathological findings by biopsy led to diagnosis of synovial chondromatosis of the right side TMJ. Extirpation of the tumor was performed via temporopreauricular incision under general anesthesia. PCNA expression was examined by immunohistochemical analysis.The lesion had penetrated into the middle cranial fossa, but the cranial dura mater was intact. Expression of PCNA was confirmed.DiscussionThe PCNA expression suggested that growth activity caused expansion of the lesion to the skull base.ConclusionWe were able to follow up this case for a long period without recurrence postoperatively.