聴神経腫ようを伴う原発性異種多発性脳腫よう ２症例の神経耳科学的検討と文献的考察

Abstract

Case 1 : right acoustic neurinoma and cerebellar tentorial meningioma. Chief complaints were dizziness, right tinnitus, right deafness and headache. Neurotological examination revealed bilateral hearing disturbance, more prominent on the right side, decreased caloric reaction on the right and defect of waves on the right side after I on an ABR. These results suggested a right acoustic neurinoma. But spontaneus downbeat nystagmus could not be explained by a unilateral cerehellopontine angle tumor, so the presence of an other lesion was suspected.Bilateral acoustic neurinoma and multiple meningiomas were found in Case 2.Our diagnosis was neurofibromatosis 2 (NF-2). The only complaint was left tinnitus. Neurotological examination revealed left hearing disturbance, decreased caloric reaction on the left, spontaneous nystagmus directed to the right, defect of waves on the left side after I and prolongation of waves I-V IPL on the right side on an ABR. The ETT and OKIN tests were normal. The x-ray findings revealed dilatation of the left internal auditory canal. Neurological examination revealed a decreased gag reflex on the left, and mild right lower extremity motor weakness. Examinations were initiated because of a suspicion of left acoustic neurinoma. Many of the test results, however, could not be explained by a left acoustic reurinoma alone, suggesting multiple lesions even before CT and MRI were performed.In general clinical medicine, the possibility of multiple lesions, as seen in the present cases, should be kept in mind during the process of neurotological and neurological examination, even in cases in which a unilateral acoustic neurinoma is suspected. Diagnostic imaging procedures, such as CT and MRI, should also be repeated until all clinical findings are explained.