Endoscopic treatment for arachnoid cyst at the cerebellopontine angle presenting with bilateral trigeminal neuralgia: Case report and literature review

Although arachnoid cysts can occur at the cerebellopontine angle or in the quadrigeminal cistern, they rarely manifest as trigeminal neuralgia. This is the first report of a patient with bilateral trigeminal neuralgia due to an arachnoid cyst at the cerebellopontine angle that has been treated effectively through pure endoscopic management. A 44-year-old woman presented with left-sided trigeminal neuralgia caused by an arachnoid cyst at the left cerebellopontine angle. At that time, the cyst was opened using an ipsilateral suboccipital approach. Twenty-three years later, she presented again with left-sided trigeminal neuralgia, and 2 months later, she became aware of right-sided trigeminal neuralgia. Magnetic resonance imaging revealed recurrence of a large arachnoid cyst at the left cerebellopontine angle extending into the quadrigeminal cistern with obstructive hydrocephalus. Endoscopic cyst fenestration through the ipsilateral lateral ventricle was performed without any complications, resulting in the complete and immediate dissipation of neuralgia and obvious shrinkage of the cyst. The trigeminal neuralgia in this case was attributed to compression of the trigeminal nerve by the cyst. In addition, the contralateral neuralgia was speculated to arise through changes in the stretch and angulation of the trigeminal nerve. Our case suggests that endoscopic treatment is an effective and less invasive procedure for cyst fenestration.