Meningiomas are tumors that originate from the arachnoidea, i.e. the middle leaf of the three meninges, and account for about 20 - 30 % of all tumors of the central nervous system. Since they originate from the meninges, they are strictly speaking not "brain tumors" but actually "meningeal tumors". In most cases they are therefore located on the surface of the brain or at the base of the skull. Very rarely they develop from scattered meninges in the depth of the brain. The vast majority of meningiomas are benign tumors (WHO grade I), i.e. they grow very slowly and initially displace brain tissue without destroying it by infiltration. This allows them to reach a considerable size before symptoms set in.
7% of all menigeomas show somewhat faster growth and the recurrence rate is increased. They are called atypical menigeomas with WHO grade II. Malignant, fast and infiltrative growing anaplastic menigeomas (WHO grade III) are very rare (2%).
Most meningiomas are singular tumors based on spontaneous gene alterations (mutations) and histologically they can be divided into 15 subclasses. They can also occur as late effects of a previous radiotherapy.
It is not uncommon for meningiomas to be discovered purely coincidental, for example during a headache examination or an accident. In such asymptomatic cases, it must be carefully decided whether surgery is necessary or whether the tumour can be controlled in regular MRI examinations. In several observational studies the rule of thumb has been established that about one third of all randomly discovered meningiomas do not grow over an observation period of 3 years.
The symptoms of meningiomas can vary greatly depending on their localization. Among other things, the following should be mentioned:
The imaging method of first choice is magnetic resonance imaging (MRI, MRI) as this method provides the best tissue differentiation and in most cases allows the reliable diagnosis of a meningioma. Especially before surgery, an additional computer tomography (CT) is performed to show tumor calcifications and the detailed spatial relationship to neighbouring skull base structures.
For symptomatic meningiomas or meningiomas that have been shown to enlarge under observation, microsurgical removal of the tumor is the therapy of choice. This means that in over 90% of cases a definitive cure can be achieved without relapse. In the case of large menigeomas with a good blood supply, it may be advisable to carry out an angiography and embolization before the operation in order to stop the blood flow in parts of the tumour. In certain cases, this method can greatly simplify tumour resection and significantly reduce the risk of surgery.
The operation is always planned in detail pre-operatively using the latest 3D methods. During the operation, finely tuned microsurgical methods and instruments are used depending on the location of the tumour. Especially at the base of the skull, endoscopic surgery is performed to identify and expose small vessels and nerves at angles that are difficult to see. The aim is always to remove the meningioma completely and to resect the part of the meninges from which the meningioma originates, i.e. the "root of the meningioma" and replace it with artificial meninges (duraplasty).
If during the operation it turns out that a complete resection is not possible, a targeted radiation treatment (Cyber-Knife) of the tumour remnants can be performed after the operation. In the vast majority of cases, this can prevent further tumour growth.
The management of meningiomas at the Hirslanden Clinic is always interdisciplinary and each individual case is discussed in our Tumour Board before and after an operation. This guarantees the best possible therapeutic method, whether with or without surgery, in accordance with international guidelines.