Beyond TMJ pain: resolution of diffuse cervicobrachialgia after excision of a TMJ synovial cyst. An atypical case report.

Synovial cysts of the temporomandibular joint are rare, typically manifesting with local symptoms such as preauricular pain and swelling; magnetic resonance imaging (MRI) is essential for diagnosis. A 45-year-old woman presented with left preauricular pain, limited mouth opening (maximum interincisal distance of approximately 24 mm), and chronic diffuse cervicobrachialgia radiating from the neck to the fingertips. MRI revealed a 6.2-mm cystic lesion at the posteromedial aspect of the left TMJ, associated with disc displacement. Surgical excision via a preauricular approach resulted in complete removal of the cyst, which was confirmed by postoperative computed tomography (CT). Cervicobrachialgia resolved within one week postoperatively. The patient also experienced transient facial paresthesia, which completely subsided within one month. These findings, together with the known overlap between TMJ and cervical innervation, suggest that TMJ synovial cyst excision may alleviate both local and referred distant pain. For general dentists, persistent preauricular pain associated with limited mandibular opening and atypical cervicobrachial symptoms should raise suspicion of intra-articular TMJ pathology when routine dental and musculoskeletal evaluations are inconclusive. Early recognition and referral for MRI assessment may facilitate definitive diagnosis and appropriate management.