To review the postoperative surgical outcomes of cystic vestibular schwannomas (CVSs), especially facial nerve outcomes, and compare these results with those from matched solid vestibular schwannomas (SVS) resected during the same period at a tertiary referral center.
Although hearing loss is the most common presenting symptom in patients with acoustic neuroma, the pathophysiology of hearing loss associated with acoustic neuroma is unknown. Although primary dysfunction of the auditory nerve is intuitively logical, available histopathologic and clinical data suggest that although neural degeneration is common, it alone does not adequately account for hearing loss in many cases. The purpose of this study was to evaluate 11 cases of unoperated unilateral acoustic neuromas. Temporal bones were identified by means of a search mechanism provided by the National Temporal Bone, Hearing, and Balance Pathology Resource Registry and were prepared for light microscopy by standard techniques. Quantification of spiral ganglion cells, hair cells, stria vascularis, and spiral ligament was accomplished for each specimen. In addition, the maximum diameter and volume of each tumor were calculated from histopathologic sections. Increasing tumor size did predict a reduced spiral ganglion count. However, although there was a tendency for decreasing spiral ganglion cell count and for increasing tumor size to predict a higher pure tone average and lower speech discrimination score, these correlations did not reach statistical significance. In tumor ears in which the speech discrimination score was 50% or less, there was always significant degeneration of other structures of the inner ear in addition to neurons, including hair cells, the stria vascularis, and the spiral ligament. Endolymphatic hydrops and eosinophilic precipitate in the perilymphatic spaces were found in 2 of 3 such cases. It is concluded that acoustic neuromas appear to cause hearing loss, not only by causing degeneration of the auditory nerve, but also by inducing degenerative changes in the inner ear. It is hypothesized that the proteinaceous material seen histologically may represent the products of up-regulated genes in acoustic neuroma, some of which may interfere with normal cochlear function.
Acoustic neuroma (AN) usually manifests with asymmetric hearing loss, tinnitus, dizziness and sense of disequilibrium. About 10% of patients complain of atypical symptoms, which include facial numbness or pain and sudden onset of hearing loss. Patients with atypical symptoms also tend to have larger tumours due to the delay in investigation. We report a particularly interesting case of a patient presented to us with numbness over her right hemifacial region after a dental procedure without significant acoustic and vestibular symptoms. Physical examination and pure tone audiometry revealed no significant findings but further imaging revealed a cerebellopontine angle mass. The changing trends with easier access to further imaging indicate that the presentation of patients with AN are also changing. Atypical symptoms which are persistent should raise clinical suspicion of this pathology among clinicians.