The neurinoma is a benign tumor that develops from the Schwann cells that form the myelin sheath covering the peripheral nerves.
This pathology can also involve the mixed nerves, namely the glossopharyngeal (IX), vagus (X), spinal accessory (XI), and hypoglossal nerve (XII), as well as the vestibular nerve; which exit at the lateral cranial base, from the brainstem through the jugular foramen along with the internal jugular vein. Like all other cranial nerves, the mixed nerves (IX-Glossopharyngeal, X-Vagus, XI-Spinal Accessory, defined as “mixed” due to their dual motor/sensory function) can be the site of origin for benign tumors that arise from their covering sheaths and are called Neurinomas or Schwannomas.

These tumors can develop along any part of the nerves; consequently, they can be located in the neck, inside the skull, or have a bilobed appearance with a component in the neck, an intracranial component, and a thinner part within the jugular foramen.
The mixed nerve neurinomas are quite rare, but due to their origin site, their surgical removal can result in significant post-operative deficits, especially if the patient is asymptomatic in the pre-operative phase.

What is an acoustic neurinoma?

The acoustic nerve neurinoma is a benign tumor that affects the eighth cranial nerve. The eighth cranial nerve is composed of two branches: the cochlear branch (essential for hearing) and the vestibular branch (essential for maintaining balance).
Symptoms vary depending on the size of the tumor and the possible involvement of surrounding nerve structures.
The neurinoma can grow to considerable sizes and may affect nearby cranial nerves or the brainstem.