A 40-year-old presents with sudden unilateral sensorineural hearing loss (60 dB), constant tinnitus, and mild imbalance for 3 months. MRI with gadolinium shows a 2 cm enhancing mass in the right internal auditory canal extending to the cerebellopontine angle. The most common origin of this mass is from which nerve?

• A Superior division of the vestibular nerve ✓
• B Cochlear nerve
• C Facial nerve
• D Inferior division of the vestibular nerve

Explanation

Acoustic neuromas (vestibular schwannomas) most commonly arise from the superior vestibular nerve (Scarpa's ganglion of the superior division), accounting for approximately 60–70% of cases. The inferior vestibular nerve is the origin in approximately 30%. Despite the name 'acoustic neuroma', they rarely arise from the cochlear nerve. This explains why hearing loss (cochlear involvement) occurs as a secondary phenomenon as the tumor compresses rather than arises from the cochlear nerve.

Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.