Abstract
A 43-year-old woman developed severe hearing loss in the right ear and equilibrium disturbance 3 years ago. Otoneurological examinations revealed a suspected acoustic neurinoma in the right. To confirm the diagnosis, labyrinthotomy was performed and took 10μl of perilymph and a part of the utricle through the oval window. The protein content of the perilymph was found to show marked elevation. The electron microscopic findings of the utricle were diseased vestibular hair cells and marked loss of nerve fibers. The thick collagen fibers were observed directly beneath the sensory epithelia. Infiltration of the erythrocytes to the perineural tissue was also found. A large amount of “banded structures” were seen in the connective tissue of the utricle. The banded structure was confirmed to be produced within fibrocytes in the perineural areas of the utricular nerve. Although it is already known that these banded structures were found in the labyrinth of Meniere's disease or cadavers, the quantity in this case was much higher.
