Acoustic Schwannoma
An acoustic schwannoma, also known as vestibular schwannoma or acoustic neuroma, is a benign (non-cancerous) tumor that develops on the nerve responsible for balance and hearing. These slow-growing tumors arise from the Schwann cells that form the protective sheath around the vestibular nerve connecting the inner ear to the brain.
What is it?
Acoustic schwannomas are benign tumors that develop on the eighth cranial nerve (vestibulocochlear nerve), which transmits sound and balance information from the inner ear to the brain. Despite being non-cancerous, these tumors can cause significant symptoms as they grow and press against nearby structures in the narrow space of the internal auditory canal and cerebellopontine angle.
These tumors account for approximately 8% of all intracranial tumors and 80-90% of cerebellopontine angle masses. They typically affect adults between ages 30-60, with an incidence of about 1 per 100,000 people per year. Most acoustic schwannomas occur sporadically, though bilateral tumors are characteristic of neurofibromatosis type 2 (NF2), a genetic disorder. The tumors grow slowly, averaging 1-2 mm per year, though growth rates can vary significantly.
Important to Know
While acoustic schwannomas are benign, they require careful evaluation and monitoring. Treatment options include observation with serial imaging for small tumors, microsurgical removal, or stereotactic radiosurgery (such as Gamma Knife). The choice depends on tumor size, growth rate, patient age, hearing status, and symptoms. Early detection through MRI is crucial, as smaller tumors offer better chances of hearing preservation with treatment. If left untreated and allowed to grow large, these tumors can compress the brainstem and cerebellum, leading to life-threatening complications.