[Diagnosis of the chiasmal meningioma (author's transl)].

Not infrequently, it is difficult to differentiate the chiasmal meningioma from other suprasellar tumors, especially pituitary adenoma and craniopharyngioma. Authors examined 7 cases of chiasmal meningioma from neurological, endocrinological and neuroradiological points of view in comparison with the cases of pituitary adenoma and craniopharyngioma. As the results, the following features can be regarded as the differential characteristics of the chiasmal meningioma. 1) It was predominated in female of over 40 years of age. 2) Duration of the symptoms before admission was usually 2--3 years. 3) Disturbance of visual acuity and defect of visual field were initially unilateral in most of the cases, then extended to the other side when the disturbance of one eye had become severe. Visual field defect tended to be of irregular bitemporal hemianopsia with frequent involvement of peripheral nasal field. 4) Evidence of the endocrine disturbance were very scanty until the end stage. 5) Postero-superior elevation of A1 portion of the anterior cerebral artery in the tuberculum sellae meningioma was one of the pathognomonic features. 6) In the case of meningioma extending from tuberculum sellae to dorsum sellae or originated from dorsum sellae, PEG showed a finding of "capping on the dorsum sellae" and the tumor shadow over the posterior clinoid process took different feature from pituitary adenoma or craniopharyngioma.