Vestibular schwannoma may present with which symptom as it enlarges?

• A. Seizures
• B. Facial numbness
• C. Bilateral hearing loss
• D. Severe headaches

Answer: (B)

Understanding how a vestibular schwannoma grows helps explain why facial numbness can appear as it enlarges. This tumor starts along the vestibulocochlear nerve (CN VIII) but, as it grows, it can extend into the cerebellopontine angle and press on nearby cranial nerves. The trigeminal nerve (CN V) provides facial sensation, so when the mass enlarges enough to involve CN V, a patient may notice numbness or altered sensation on the face on the affected side. This mass effect is a direct consequence of the tumor’s growth and its location near multiple cranial nerves.

While unilateral hearing loss and tinnitus are common early signs due to CN VIII involvement, seizures are not typical because these tumors are extra-axial and rarely cause cortical seizures. Severe headaches can occur with intracranial pressure but aren’t characteristic of vestibular schwannoma specifically, and bilateral hearing loss would suggest involvement of both sides, as seen in certain conditions like NF2, which is less about progressive enlargement on one side. Facial numbness reflects the tumor’s extension to adjacent nerves as it enlarges, making it a plausible symptom in this context.