Neurocytoma of the VIIIth cranial nerve: case report.

Abstract

Neurocytomas are uncommon tumors of the CNS. To date, none have been described in association with a cranial nerve. We described the clinicopathological features of an example arising in the cochlear-vestibular portion of the VIIIth nerve with extension into the cerebellopontine angle. The patient, a 42-year-old female, presented approximately 6 months ago with several episodes of worsening dizziness. On magnetic resonance imaging studies, a 2-cm enhancing lesion occupying the left internal auditory canal and protruding into the cerebellopontine angle cistern was detected with signal characteristics suggestive of vestibular neuroma. At surgery, the tumor was seen to originate from the cochlear-vestibular nerve bundle lying within the internal auditory canal, extended laterally to the level of the fundus and 4 mm medially into the cerebellopontine angle. No dural attachment was noted. With use of sharp dissection and bipolar cautery, portions of the tumor within the auditory canal were debulked. A unique example of a neurocytoma in association with a cranial nerve is documented. Possible explanations for the occurrence are explored. The topography of neurocytomas continues to expand.