Definition and General Information: Meningiomas are brain tumors with generally benign behavior originating from the arachnoid membrane of the brain. Meningiomas, which make up about a quarter of all brain tumors, can be seen at any age, but are twice as common in middle-aged women as in men.
Causes: Recent studies have revealed that the dysfunction of both copies of the NF2 gene, which is tumor suppressor, in DNA plays a central role in the formation of meningiomas. However, research on obtaining tumor stem cells that may be responsible for the formation of these types of tumors is still ongoing (Serdar Baki Albayrak, Peter Black, The Origin of Meningiomas, Chapter 3, MENINGIOMAS, A Comprehensive Text). There are publications that externally taken female hormone supplements and pregnancy increase the growth rate of meningiomas. Head trauma and radiation applied to the skull and brain have also been shown to be associated with meningioma formation.
Types and Tumor Behavior: According to the World Health Organization’s 2000 regulation, meningiomas are histopathologically grade 1 (benign, 80%), Grade 2 (atypical, 15%) and Grade 3 (malignant, 3 -5%) are divided into three groups. In the group that is Selim, mainly; There are microcystic, lymphocytic, metaplastic, secretory, psammomatous, and angiomatous subtypes, with meningothelial, fibrous, and a mixture of the two. In this benign group, the lifetime recurrence rate after surgery varies between 5 and 25%, and there is a relationship between the tumor tissue volume that cannot be removed and the recurrence rate. Grade 2 consists of chordoid, clear cell and atypical meningiomas. The long-term recurrence rate of tumors in this group is between 30-50%. Papillary, rhabdoid and anaplastic meningiomas are malignant tumors included in the 3rd degree group and always recurring. The lack of binding site of the female hormone progesterone in the meningioma tumor tissue, the high rate of tumor division (more than 6 dividing cells per 16 mm2 area under the microscope at 10 magnification), and the presence of anaplastic type meningiomas are factors that negatively affect the life span.
Treatment: The first treatment method in meningiomas is microsurgical approach and radical total tumor removal is planned that causes no or minimal functional-structural loss in the patient. In the first surgery, if possible, it should be aimed to completely remove the dura, the outer membrane of the brain to which the meningioma adheres. In atypical and malignant meningiomas, post-surgical radiotherapy and/or chemo-hormonal treatments are added to the treatment scheme.
