Neurocytoma of the VIIIth cranial nerve: Case report

OBJECTIVE AND IMPORTANCE: Neurocytomas are uncommon tumors of the CNS. To date, none have been described in association with a cranial nerve. We described the clinico-pathological features of an example arising in the cochlearvestibular portion of the VIIIth nerve with extension into the cerebellopontine angle. CLINICAL PRESENTATION: 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 cerebello-pontine angle cistern was detected with signal characteristics suggestive of vestibular neuroma. INTERVENTION: At surgery, the tumor was seen to originate from the cochlear-vestibular nerve bundle laying 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. CONCLUSION: 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.