 - Progression is defined on 2 different MRI as an increase of meningiomas surface 5 by 3 months period i.e. an increase of 5 over 3 months, 10 over 6 months, 15 over 9 months... or as the apparition of a new unequivocal neurological symptom related to the meningioma. We considered as a new unequivocal neurological symptom a new occurring neurological symptom as, for instance, hemiparesia, oculomotor nerve palsy, visual loss, facial nerve palsy, facial neuralgia, directly related to meningioma and suggesting meningioma growth with increase of meningioma compression on neurological structures despite no increasing size on MRIs. 