Symptoms
The neurinoma itself is movable and not painful. Hearing loss (hypacusis) is the most common symptom and takes a gradual course due to the slow growth of the neurinoma. Occasionally, patients complain of hearing disorders when using the telephone and describe a change in their telephone calling habits by changing the receiver to the opposite ear.Other early signs are ringing in the ears (tinnitus), dizziness when changing position quickly and uncertainty when turning around quickly.
As the disease progresses, there is permanent dizziness, disturbances in movement coordination (ataxia), especially gait insecurity and a spontaneous, rapid resetting movement of the eyeball (spontaneous nystagmus). As the tumor continues to grow, the brain nerves, brain stem and cerebellum become trapped. If the facial nerve (nervus facialis) is affected, paralysis of the mimic muscles (facial paresis) may occur.
If the triplet nerve (nervus trigemus) is affected, the face may feel numb, spontaneous attacks of pain in the head area (trigeminal neuralgia) and taste disorders may occur. Constriction of the cerebellum leads to ataxia, while constriction of the brainstem causes an increase in intracranial pressure and characteristic cerebral pressure symptoms (nausea, vomiting, etc.). The 4th ventricle, a cavity in the cerebrospinal fluid (cerebrospinal fluid), can also be constricted.
This leads to a congestion and thus to a disturbance of the cerebrospinal fluid’s circulation, but this occurs rarely and only in the case of very large tumors. Neurinomas in the spinal canal usually constrict the nerve roots of the sensitive nerves. As a result, the patient experiences unilateral, radiating (radicular) pain in the skin area (dermatome) belonging to the respective sensitive nerve.
The pain increases as the pressure in the spinal canal increases until it decreases again and finally stops when the root of the sensitive nerve is completely destroyed. As the pain progresses, asymmetrical paraplegia can slowly develop, even if the nerve roots of the nerves that control muscle movement (motor nerves) are pinched. The neurinoma itself is not painful.
However, due to its suppressive growth in the area of the nerve sheath, there is always a risk that the adjacent nerve will be compressed or irritated. As a result, the patient may experience very severe pain. This typically occurs at rest, as the tumor permanently presses on the nerves.
The pain can be intensified by touching the nodular tumor mass or by stress. Treatment with painkillers can temporarily relieve the pain, but in the case of massive pain, surgical removal of the tumor is usually necessary. For an exact diagnosis and to plan the later treatment, imaging sectional imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI of the head) are used.
This involves taking tomograms of the entire body from the vertex to the feet, which are then combined to form a complete three-dimensional image. An indirect indication of a neurinoma is the widening of the internal acoustic canal, which can be seen in the CT. In general, however, it is very difficult to differentiate between nerve and tumor tissue in a CT scan.
Therefore, MRI of the brain is the method of choice for detecting neurinomas and for imaging the spatial extension of cerebellar bridge angle tumors. Another important point for diagnosis is a significant increase in the protein content of the cerebrospinal fluid. When diagnosing hearing disorders, it should be kept in mind that only 5% of these patients have an acoustic neuroma.
The diagnosis of hearing disorders is determined by audiometry, calorimetry and acoustically evoked potential (AEP). For example, the response of the auditory cells and the different stations of the auditory pathway in the brain to acoustic stimuli is measured. Magnetic resonance imaging (MRI) is the method of choice for diagnosing neurinomas.
In computer tomography (CT), it is difficult to differentiate between neurinoma and surrounding tissue. In an MRI examination, this contrast is better. By administering contrast medium, the size of the tumor can be assessed even better, since the contrast medium accumulates in the neurinoma. In comparison to other tumors in the area of the peripheral nervous system, neurinomas often show a cystic image (several cavities) as well as a greasy remodelling of the tissue. In some cases, bleeding may also occur, which can be easily assessed with the administration of contrast medium.
