[Trigeminal neurinoma associated with suprasellar arachnoid cyst]

A rare case of trigeminal neurinoma associated with suprasellar arachnoid cyst is reported. A 49-year-old female had been suffering from character change, memory disturbance and mild headache for three years prior to admission. On admission, there were bilateral choked disc and binasal lower quadrant anopsia. Visual acuity was 20/200 on the left side and 10/200 on the right side. Facial and auditory nerves were intact. Cerebellar sign was not present. In plain skull roentgenograms, there were destruction of the right apex of the pyramis. However, the internal auditory meatuses were normal. Computed tomography revealed a contrast enhanced mass at the right cerebellopontine angle and a large cystic lesion in the suprasellar region. The relation between both lesions was clearly demonstrated in the coronal computed tomography and the NMR imaging of the sagittal section. The patient was operated on through subtemporal approach. The well-defined yellowish tumor was totally removed and the cyst was opened. The tumor and the cyst were distinguished separately. Post-operative course was uneventful except for the right trigeminal palsy. Mental symptoms disappeared. The mechanism of the appearance of symptoms in the case is considered as follows. That is, the slowly expanding tumor progressively compressed the cyst and the cyst enlarged, then the various symptoms appeared. The possibility that the suprasellar arachnoid cyst was a secondary arachnoid cyst due to the trigeminal neurinoma is also discussed.