PMC9681896_01
Pure-tone audiogram at the initial visit showed almost normal hearing threshold on both sides (A). Audiogram 4 years after the initial visit revealed moderate sensorineural hearing loss in the right ear at low and middle frequencies (B). Audiogram after treatment with corticosteroid with partial hearing improvement (C). Audiogram 6 years after the initial visit showed mild hearing loss in the right ear only at low frequencies (D). Audiogram 7 years after the initial visit revealed severe hearing loss in the right ear at all frequencies (E). Audiogram 12 years after the initial visit showed profound sensorineural hearing loss in the right ear (F).
fneur-13-1043452-g0001.jpg
PMC9681896_01_fneur-13-1043452-g0001.jpg
F1
Audiogram showed almost normal hearing level (Figure 1A). Audiogram revealed moderate right sensorineural hearing loss particularly at low frequencies (Figure 1B). Thereafter, partial hearing improvement was observed (Figure 1C). Results showed moderate hearing loss in the right ear at low frequencies (Figure 1D). Audiogram revealed moderate sensorineural hearing loss at all frequencies in the right ear (Figure 1E). Audiogram revealed profound sensorineural hearing loss in the right ear (Figure 1F).
Axial magnetic resonance (MR) images obtained from a patient with concurrent right intravestibular schwannoma and endolymphatic hydrops in the right cochlea. (A) MR cisternography images obtained 4 years after the patient's initial visit to our department. (B-D) MR images obtained 12 years after the patient's initial visit to our department. (A,B) MR cisternography revealed a filling defect in the right vestibule (asterisks). (C) Gadolinium-enhanced T1-weighted imaging showed an enhanced region in the right vestibule indicating the presence of a hypervascular mass (asterisk). (D) Delayed 3D-FLAIR image, subtraction of the positive endolymphatic image from the positive perilymphatic image revealed black areas (arrowheads) representing the right cochlear hydrops and diffuse perilymphatic hyperintense area (arrowhead) indicative of blood-labyrinth barrier impairment.
fneur-13-1043452-g0002.jpg
PMC9681896_01_fneur-13-1043452-g0002.jpg
F2
However, a filling defect of fluid intensity was detected in the vestibule of the right ear, and this finding was overlooked by an otolaryngologist and a radiologist (Figure 2A asterisk). MRI was performed to confirm endolymphatic hydrops or identify other conditions. MR cisternography showed a filling defect of fluid intensity in the vestibule of the right ear (Figure 2B asterisk). Gadolinium-enhanced T1-weighted imaging revealed a moderately enhanced region in the right vestibule, which indicated a hypervascular mass in the right vestibule (Figure 2C asterisk). Delayed 3D-FLAIR MRI showed endolymphatic hydrops in the right cochlea (Figure 2D arrows) with a stronger signal intensity in the scala tympani in the basal portion of the cochlea (Figure 2D arrowhead) than in the contralateral ear.
VEMP and vHIT. (A) oVEMP (500-Hz bone conduction) and cVEMP (500-Hz air condition). The patient had normal oVEMP and cVEMP on the unaffected side (left ear), and she presented with abnormal oVEMP and cVEMP in the affected side (right ear). (B) vHIT showed hyporeflexia in the anterior and posterior semicircular canals of both ears. Meanwhile, vHIT of the left lateral semicircular canal was normal, and vHIT of the right lateral semicircular canal had covert saccades (arrow), which indicated that the right lateral semicircular canal had decreased function.
fneur-13-1043452-g0003.jpg
PMC9681896_01_fneur-13-1043452-g0003.jpg
F3
Both cervical and ocular vestibular evoked myogenic potential (cVEMP and oVEMP) were not detected upon right ear stimulation (Figure 3A). This result indicated decreased right lateral semicircular canal function (Figure 3B).
Intraoperative findings. After cortical mastoidectomy (A) and labyrinthectomy (B), a pink mass was observed in the right vestibule (arrow) (C). After tumor resection, the intravestibular region was evaluated both microscopically (D) and endoscopically (E). An 8-mm mass was excised (F). (G) High-power microphotograph showed a nuclear palisading pattern. Scale bar = 100 mum.
fneur-13-1043452-g0004.jpg
PMC9681896_01_fneur-13-1043452-g0004.jpg
F4
Thus, surgery using the translabyrinthine approach was performed (Figure 4).