Acoustic neuroma (vestibular schwannoma): A literature review

Abstract

Acoustic neuroma is the most frequent ponto cerebellar angle tumor. Genetic factors are involved in its etiology, and in occasions its origins can be linked to diseases such as bilaterally expressing type 2-neurofibromatosis. Clinically, acoustic neuromas can be classified in 4 stages, which result in diverse symptoms, according to the degree of brain stem and internal auditory canal compression or obstruction; however, hearing loss remains as the most important presenting symptom. The four stages are: intracanalicular, cisternal, brain stem compressive and hydrocephalic. Frequently they reach between few millimeters to more than 3 centimeters in diameter, and are accordingly ranked as small, medium-sized, and large. They have been reported as having slow growth and uncertain natural history; in most studies growth rates fluctuate between 1-3 mm/year. Pure tone audiometry is the procedure of choice for diagnosis orientation in the first place, however, gadolinium-contrasted magnetic resonance imaging is currently pivotal for diagnosis confirmation. As for management, there are three reasonable alternatives, depending on a given case particularity. These are monitoring, microsurgery and stereotactic radiotherapy or gamma knife. Each one of them has its pros and cons, and thus the final therapy decision will depend on the symptoms and tumor growth rate and size, priorizing the patient well-being.