Normal opaque cerebellopontine cisternogram.

An attempt has been made through this study to establish a tumor suspect pool of 100 patients, each one highly suspect because of a single or usually several strong clinical indicators of a retrocochlear lesion. In turn each patient has been proven tumor negative by virtue of a normal opaque cerebellopontine cisternogram. This has given us a unique opportunity to critically reassess the clinical indications of VIIIth nerve tumor from a reverse or negative viewpoint. All data from these patients has been carefully analyzed in relation to indication for opaque cisternography, clinical symptomatology, vestibular function, final etiologic diagnosis, and the associated special auditory tests, tomograph of the internal auditory canal, the associated vestibular aqueduct findings. This paper parallels our earlier study of 121 surgically proven schwannomas providing a total tumor suspect pool of 221 patients with a comparable tumor positive-tumor negative distribution.