**3. Clinical presentation**

Surgery represents the mainstay of the treatment, but the management of more aggressive meningioma is challenging. The role of adjuvant therapies should thus be discussed in cases of

Meningiomas account for 20 and 38% of all primary intracranial tumors, respectively, in males and in females, with an incidence of about five cases per 100,000 persons [5]. In an autoptic series about 2–3% of the general population had an incidental asymptomatic meningioma [6]. The female sex and estrogenic conditions seem to be a risk factor for developing meningio‐

Hormonal therapy and hormone-dependent conditions such as breast cancer [8], pregnancy [9], or obesity [10] were in fact associated with a higher incidence of meningiomas. Cranial irradiation is also a recognized risk factor for developing meningiomas, usually with tumors having a more complex cariotype and a more aggressive behavior [11]. Head traumas have been for long associated with a higher meningioma incidence, but the causal effect was never

Some genetic conditions may favor the arising of meningiomas, such as neurofibromatosis type 2 (NF2), an autosomal dominant disorder characterized by mutation of the tumor suppressor gene NF2 coding for merlin in chromosome 22q12.2. Also multiple endocrine

Meningiomas may derive from the dura of the cranial vault, of the skull base and at sites of dura reflection like the falx, the tentorium, and the dura recovering venous sinuses. Meningiomas may also arise from the optic-nerve sheath and from the choroid plexus. About 10% of them arise in the spine. In rare cases, meningiomas outside the craniospinal axis have been reported [12]. The preferential localization of intracranial meningiomas is summar‐

neoplasia type 1 (MEN1) is associated to a higher incidence of meningioma.

**Figure 1.** Graphic representation of the topographic distribution of intracranial meningiomas.

more aggressive histological types, subtotal resection and recurrent diseases.

**2. Epidemiology**

362 Neurooncology - Newer Developments

demonstrated.

ized in **Figure 1**.

mas, with a female to male ratio of about 3:1 [7].

In many cases, meningiomas are asymptomatic and discovered in the context of investiga‐ tions of unrelated symptoms [16]. When symptomatic they may determine epileptic seizures or focal neurological deficit according to the irritation or the compression of eloquent areas or vasculo-nervous structures. Hydrocephalus may be secondary to meningiomas obstructing the physiologic CSF flow. An increased intracranial pressure may be present in cases of voluminous lesions or with an associated peritumoral edema.

Focal neurological deficit is directly linked to the localization of the tumor, according to the compression of cranial nerves or specific hemispheric regions. Spinal tract compression is also typical for spinal meningiomas.
