Occult intralabyrinthine schwannoma.

Report of a case of an intralabynrinthine schwannoma discovered unexpectedly during a labyrinthectomy for intractable vertigo, and description of the light and electron microscopic appearances. Although only 18 of these tumors have been previously reported, it is possible that some cases which are categorized as peripheral vertigo of unknown origin, may be due to an occult Schwannoma. All material removed during surgical procedures on the inner ear should therefore be submitted for histopathological examination.