Vestibular sensory epithelia in patients with acoustic neurinoma.

The human vestibular sensory epithelia of the macula utriculi were examined ultrastructurally in 13 cases with acoustic neurinoma. The sensory epithelia were fairly well preserved, with several morphological changes such as lipofuscin granules, intraepithelial cysts, pyknosis, vacuoles, laminated structures, banded structures and degeneration of subepithelial myelinated nerves evident. The pathological significance of these findings was discussed. There were thickened irregular membrane formations in spaces between the nerve calyces and type I hair cells which might be related to acoustic neurinoma. Some type I hair cells were incompletely surrounded by nerve calyces. The neck regions of these cells received direct contact from the efferent nerve endings.