Symptoms, diagnosis & therapy
Acoustic neuroma is a benign tumor that usually arises from the Schwann cells of the vestibular nerve and in rare cases also from the Schwann cells of the cochlear nerve. The Schwann cells build an electrical insulation layer, enveloping the nerve on the outside. Hence it is also termed vestibular schwannoma.
The acoustic neuroma is a very rare tumor, the incidence of which, however, increases with increasing age. Normally, it grows very slowly. Depending on its localization, two forms of the tumor are distinguished: medial tumor and lateral tumor.
A characteristic element of acoustic neuroma is a one-sided onset of symptoms, i.e. only one ear is affected. Basically, there are three very typical symptoms. Therefore, doctors speak of a so-called triad of symptoms. Most of the time, the first sign for the acoustic neuroma is a one-sided loss of hearing. This can either occur suddenly in the form of an acute hearing loss or slowly in the form of worsening hearing impairment. Additionally, acoustic neuroma patients often suffer from ringing in the ears (tinnitus). Moreover, there is usually a dysfunction of the vestibular apparatus and hence dizziness and nystagmus (rapid, involuntary movements of the eye). Occasionally, the acoustic neuroma causes facial pain or numbness in the jaw area.
Possible complications include nausea, vomiting, and movement disorder. These symptoms only appear when the tumor has reached a sizeable mass and begins applying pressure on the brainstem.
Diagram: The location of the tumor on the nerve is such that its weight can prevent the blood supply necessary for proper nerve function (vascular compression).
Therapy of acoustic neuroma
Usually, acoustic neuromas larger than 1 inch in diameter are removed surgically, given the general condition of the patient allows it. If the tumor is smaller than 1 inch, there usually are two different approaches: The first method consists of waiting and regularly monitoring the tumor until it is large enough for surgical removal. The second option is a so-called stereotactic radiosurgery. Hereby the acoustic neuroma is treated with a very high dose of radiation in order to completely destroy it.