[Trigeminal neuralgia secondary to petrous endostosis].

Arterial neurovascular compression is hypothesised to be the main cause of primary trigeminal neuralgia. Although it is the most common cause, other pathologies, such as tumours in the cerebellopontine angle, can cause trigeminal pain. We report a case of a 44-year-old female patient with right trigeminal neuralgia without satisfactory response to medical treatment. Cerebral MRI showed no structural injuries. During microvascular decompression of the trigeminal nerve, endostosis of the internal aspect of the petrous bone was found to compress the trigeminal nerve. The pain disappeared completely in the early postsurgical period, after the complete drilling of the endostosis and microvascular decompression. The patient remains asymptomatic one year later. Endostosis of the petrous bone is a rare cause of trigeminal neuralgia. A proper review of preoperative studies would enable the definitive surgical approach to be optimised.