Management of Rare Temporomandibular Joint Cysts with Intracranial Extension: A Case Series and Literature Review

Objective: Temporomandibular joint (TMJ) cysts extending through the skull base into the middle cranial fossa (MCF) are extremely rare but in the differential of extra-axial cystic lesions in this location. There are limited reports documenting clinical course and treatment options of TMJ processes with intracranial extension.

Methods: Patients with imaging showing TMJ cysts eroding into the MCF were identified retrospectively at a tertiary care center. Patient evaluation by a multidisciplinary team included otolaryngology, oral and maxillofacial surgery, neurosurgery, and neuroradiology. Clinical and imaging findings at presentation, surgical resection, and follow up were evaluated. Literature review was conducted for TMJ pathology with or without intracranial extension.

Results: Three patients presenting with long-standing otalgia and TMJ tenderness were found to have intracranial cysts communicating with the TMJ. Two were transfers from outside hospitals due to concern for intracranial abscess; one for workup of headache and trigeminal neuralgia. One patient had pneumocephalus within the intracranial cyst. All three demonstrated slight elevation of inflammatory markers, one had leukocytosis, and one had frank purulence on needle aspiration of the TMJ. The bony defects ranged from <1 to 4 mm. The intracranial cysts ranged from 1.2 to 3.3 cm in maximum diameter, with thickness from the inner table less than 1 cm. Two underwent craniotomy, cyst resection, and repair of middle fossa defect. One elected to monitor due to medical co-morbidities. Intraoperatively, white gelatinous fluid was encountered at cyst resection. Pathology review demonstrated benign cysts, one with crystal deposition.

Discussion: There have been only 30 reported cases of TMJ cysts. Despite the normally thin intervening bone of the glenoid fossa which averages less than 1 mm, only 3 of these reported cases demonstrated intracranial extension. Potentially erosive processes include synovitis, degenerative cysts, septic arthritis/abscess, synovial chondromatosis, giant cell tumors, and other primary tumors of cartilage and bone. Cysts may have rim enhancement, central fluid, and air even without active infection. These are easily differentiated from solid tumor, and the lack of restriction on MRI DWI sequences can differentiate from abscess, impacting acuity and appropriate patient management. Despite being a benign process, open communication to the MCF may predispose to infection, prompting surgical repair. In our two patients, repair was performed with fascia lata and/or bone cement and resulted in pain relief. Free fat graft, pedicled muscle grafts, and bone grafts have been described for repair of MCF defect into TMJ. Two previous reports also described patients with facial paralysis or numbness that resolved after surgical removal.

Conclusion: TMJ cyst with intracranial extension is a rare entity which can be mistaken for intracranial abscess. Continuity with the joint, lack of water restriction, and lack of clinical signs of infection can be helpful to triage surgical urgency. However, the cysts may result in pneumocephalus and may predispose to future infection. Surgical removal of the cyst and repair of the skull base can relieve symptoms and prevent future complications ([Figs. 1]–[3]).

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Publication History

Article published online:
15 February 2022