Small vestibular schwannoma presented with trigeminal neuralgia: illustrative case.

BACKGROUND:A vestibular schwannoma (VS) presenting with paroxysmal facial electric shock pain, that is, trigeminal neuralgia (TN), is relatively rare. Furthermore, TN is extremely rare in small VSs. OBSERVATIONS:Herein, the authors report the case of a 52-year-old woman with a complaint of right TN. Magnetic resonance (MR) imaging revealed a right VS of 12-mm diameter that compressed the trigeminal nerve. Although she did not report any hearing impairment, audiometry revealed decreased high-frequency range on the right side. The tumor was excised using the right retrosigmoid approach, and TN was confirmed to be caused by direct compression of the trigeminal nerve by the VS. Sufficient decompression of trigeminal nerve was done. The proximity of the trigeminal nerve root to the vestibular nerve root was the cause of TN. TN disappeared immediately after surgery, and there was no worsening of hearing impairment and facial paralysis. LESSONS:It is important to remember that TN may occur with direct tumor compression, even in small VSs. A preoperative 3-dimensional MR cisternogram/angiogram fusion image clearly showed direct tumor compression of the trigeminal nerve and the absence of responsible vessels, which was useful for surgical planning.