Cranial Nerve Tumors

The diagnostic workup for suspected cranial nerve tumors centers on high-resolution magnetic resonance imaging (MRI) with gadolinium contrast, which provides excellent soft-tissue detail and characteristic imaging features for most tumor types. For suspected vestibular schwannoma, a formal audiological assessment — including pure-tone audiometry and speech discrimination testing — is a routine part of the initial evaluation, both to characterize hearing loss and to establish a baseline before any treatment. Auditory brainstem response (ABR) testing may also be used to assess cochlear nerve function. When vascular tumors such as paragangliomas are suspected, CT angiography or formal catheter angiography helps delineate the blood supply and guides preoperative planning.

Treatment strategy is individualized and ranges from active surveillance to surgery or radiosurgery. Small, slow-growing tumors in patients with good hearing or those who are older and have few symptoms may be managed conservatively with periodic MRI monitoring, an approach sometimes called "watch and wait." Microsurgical resection remains the definitive treatment for larger tumors or those causing progressive neurological deficits. The surgical approach is selected based on tumor size, location, and preoperative hearing level. Stereotactic radiosurgery (Gamma Knife) offers excellent tumor control rates for tumors up to approximately three centimeters in diameter, with lower rates of cranial nerve injury than open surgery in appropriately selected cases. For patients with NF2 (Neurofibrmatosis Type 2), treatment planning must account for the bilateral nature of disease and the particular importance of hearing preservation.