Vestibular schwannoma (acoustic neuroma) most commonly arises from which specific cell population and at which anatomical location within the internal auditory canal?

• A Hair cells of the cochlea at the modiolus
• B Oligodendrocytes of the vestibular nerve within the posterior fossa cistern
• C Schwann cells at the Obersteiner-Redlich zone (CNS-PNS junction) of the superior vestibular nerve ✓
• D Melanocytes in the spiral ligament

Explanation

Vestibular schwannomas arise from Schwann cells at the Obersteiner-Redlich zone — the CNS-PNS transition zone where central myelin (oligodendrocyte-derived) transitions to peripheral myelin (Schwann cell-derived). This zone for the vestibular nerve is located just within the internal auditory canal. The superior vestibular nerve is more commonly the site of origin than the inferior vestibular nerve or cochlear nerve. This explains why these tumours arise in the IAC, produce early IAC expansion on imaging, and initially cause vestibular symptoms before significant cochlear involvement.

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.