A 43-year-old man had the sudden onset of vertigo, followed 5 days later by left-sided facial palsy. On admission, he was unable to ambulate because of the severe vertigo, which was associated with spontaneous nystagmus beating toward the right side. He denied having any systemic diseases. An examination of the ear, nose, and throat failed to show any eruption or vesicle formation. There was no evidence of otalgia or neuralgia. Evaluation of facial nerve function revealed no abnormalities on the right side, but a House-Brackmann grade IV/VI paralysis was observed on the left side. Audiometry showed normal hearing in both ears. Caloric and vestibular evoked myogenic potential tests revealed normal responses in the right ear but absent responses in the left ear. An axial T1-weighted postgadolinium fat-saturated image demonstrated a linear-enhanced soft-tissue mass measuring 0.2 cm in greatest dimension in the left internal auditory canal (Figure 1, arrow), without significant expansion of the nerve in the middle ear or internal auditory canal, while the right internal auditory canal was intact. Also, there was enhancement of the labyrinthine segment of the facial nerve on the left side (Figure 1, arrowhead), yet the right side was normal. Furthermore, the geniculate ganglia showed bilateral enhancement but much more so on the left side.
Chien-Le Li, Chun-Nan Chen, Yi-Ho Young. Radiology Quiz Case 2. Arch Otolaryngol Head Neck Surg. 2009;135(2):210–214. doi:10.1001/archoto.2008.534-a