65-year-old male presents with left sensorineural hearing loss.


MRI images demonstrate an avidly enhancing, T1-isointense, T2-hypointense lesion in the basal turn of the cochlea, characteristic of schwannoma. The T2 hypointesity appears as a filling defect within the surrounding hyperintense perilymph fluid.

Acute labyrinthitis is characterized by T1 hyperintense signal secondary to permeability of the blood-labyrinth barrier and accumulation in the intralabyrinthine compartment. Post-gadolinium T1-weighted images demonstrate diffuse, but faint, enhancement of the labyrinth. Intravestibular lipomas are nonenhancing and demonstrate T1 hyperintense, T2-iso, or hypointense signal with complete saturation on fat-saturation images. Intralabyrinthine hemorrhage is  characterized by both T1- and T2-hyperintense signal on precontrast sequences.


Vestibular schwannoma is a benign nerve sheath neoplasm derived from perineural Schwann cells. They are similar in pathology to peripheral schwannomas and comprise approximately 8% of adult intracranial tumors. Median age at diagnosis is 50, and they are rare in children unless associated with neurofibromatosis type 2 (NF2). The majority of these tumors (90%) are unilateral, with bilateral involvement characteristic of NF2.  In sporadic cases, there is often biallelic inactivation of the NF2 gene, which produces schwannomin and serves as a tumor suppressor. Childhood exposure to radiation increases the risk for developing vestibular schwannoma in later life.

Presenting symptoms include hearing loss and tinnitus (cochlear nerve) or unsteady gait and vertigo (vestibular nerve) depending on the affected nerve. 

Patients who are young, have large tumors and/or significant hearing loss should be treated early to prevent progressive hearing loss. In older patients with small tumors and minimal hearing loss, rate of growth may be used to guide treatment, with rapid growth defined as  > 2.5 mm per year.

1. Park JK, Vernick DM, Ramakrishma N. Vestibular schwannoma (acoustic neuroma). http://www.uptodate.com/contents/vestibular-schwannoma-acoustic-neuroma

2. Salzman KL, et al. Intralabyrinthine schwannomas: imaging diagnosis and classification. 

Image IQ: 65-year old Male, Left Sensorineural Hearing Loss