Meningioma

A meningioma ( syn.: meningioma, Meningeoma, English:. Meningioma ) is a mostly benign ( " benign " ) brain tumor. It is caused by the degeneration of cells of the arachnoid ( a meningeal layer). It is characterized by its slow and displacing growth. Malignant ( " malignant " ) degeneracies are rare. 20-25 % of all primary central nervous system tumors are meningiomas.

Occurrence

The main age of onset is in the fifth decade of life, with women being affected more often in the ratio 3:2. Multiple occurrence of meningiomas is characteristic for the neurofibromatosis type 2 Solitaire in 98 % of cases. Dental x-ray diagnostics in history ( in childhood and at least annually in adults) the risk increases tend not to suffer from a meningioma.

Pathology

In most cases, meningiomas are at the falx cerebri, the sphenoid wing, at the Olfaktoriusrinne and consist usually good from the adjacent brain tissue. The cut surface looks gray and grainy. In some forms can be observed in the microscope an onion skin formation of tumor cells. Calcification of these, they are called psammoma bodies.

According to the WHO classification of tumors of the central nervous system 3 histological types are currently known, depending on the frequency of recurrence and prognosis than grade I ( benign ), grade II ( atypical meningioma, rapid growth, frequent recurrences ) grade III (anaplastic meningioma, malignant, be classified infiltrative growth). Grade II and III meningiomas have a frequency of about 20 %.

Gross: encapsulated, round, gray-white tumors of plump - elastic and firm consistency. They attach firmly to the dura and compress the adjacent brain tissue. Often a dura and / or bone infiltration with hyperostosis of the adjacent bone occurs. The meningiomas are hypervascular, it can form furrows in the bone (see sulci arteriosi by meningeal artery ).

Symptoms

The patient's complaints include headache and neurological deficits. The growth of meningiomas during pregnancy may run accelerated, a possible explanation are regularly present in the tumor cells progesterone receptors. Randomly discovered meningiomas may also cause no symptoms and need, if they do not grow quickly, are not necessarily operated on.

Diagnostics

The imaging method of choice is the meningioma the MRI, because this method has the largest soft-tissue contrast and in typical cases enables reliable diagnosis of a meningioma. In T2 - weighted images to represent calcified meningiomas in contrast to many other tumors as a black mass ( hypointense ), which is darker than the surrounding brain tissue. Uncalcified meningiomas may be isointense to the environment. From other tumors, meningiomas differ by their location on the dura mater with characteristic slopes in the dura ( dural tails ) and a very intense contrast uptake. Computed tomography can demonstrate the tumor calcifications very good. Conventional X-ray angiography and today have only a untergeordnetete importance.

Most meningiomas grow spherical or globular while retaining its solid mass. In some cases, they can break through the meninges or bones. In addition, we observed preferably in the sphenoid a plaque-like propagation.

Contrast agent receiving meningioma of the left hemisphere in computed tomography

Large Felsenbeinmeningeom in computed tomography

Typical marginal localization of a meningioma right ( MRI, T1 - weighted with contrast )

Falxmeningeom in MRI: T1 contrast agent

Meningioma in the spinal canal MRI. Links sagittal T1 with contrast, right T2 coronal

Therapy

The neurosurgical removal of the tumor is the treatment of choice. One option may be the preoperative embolization here in vascularized tumors. Possibly can also radiotherapy or radiosurgery ( Gamma Knife or CyberKnife ) are performed. Small meningiomas without growth tendency in older people may not necessarily be removed.