Ganglion cyst of the temporomandibular joint with intradural extension: case report.

Intracranial extension of temporomandibular joint (TMJ) ganglion cysts is very rare. Two previously reported cases presented clinically due to effects on cranial nerves and had obvious association with the TMJ on imaging. To the authors' knowledge, intracranial extension of a TMJ ganglion cyst presenting with seizures and mimicking a primary brain tumor has not been previously reported. The patient underwent resection of a presumptive primary cystic temporal lobe tumor, but the lesion had histopathological features of a nonneoplastic cyst with a myxoid content. He was followed with serial imaging for 5 years before regrowth of the lesion caused new episodes of seizures requiring a repeat operation, during which the transdural defect was repaired after the adjacent segment of the TMJ was curetted. A thorough review of all imaging studies and the histopathological findings from the repeat operation led to the correct diagnosis of a TMJ ganglion cyst. This case highlights an unusual presentation of this rare lesion, as well as its potential for recurrence. TMJ ganglion cysts should be included in the differential diagnosis of cystic tumors involving the anterior temporal lobe, presenting with or without seizures. Focused imaging evaluation of the TMJ can be helpful to rule out the possible role of associated TMJ lesions.