Title: Primary intracranial leptomeningeal glioma with persistant hypoglycorrhachia.
Abstract: Metastatic involvement of the leptomeninges by malignant gliomas, such as glioblastoma multiforme and medulloblastoma, is not unusual.However, gliomas grossly appearing to arise in the lepto- meninges are rare, and may assume one of two forms: (1) the meningeal tumour may be entirely extracerebral and have no demonstrable connexion with the underlying neuraxis, or (2) it may grow largely in the subarachnoid space, but with definite connexions to the superficial layers of the adjacent cortex.An example of the second type is offered in the present case, where a well-differentiated astro- cytoma was grossly identifiable only in the sub- arachnoid space of the right Sylvian fissure, but microscopically it extended into the cerebral perivascular spaces and invaded the cerebral cortex through breaks in the adventitia-glia membranes.The exact site of origin cannot be determined, but it is assumed that the existence of subarachnoid glial heterotopias facilitated this unusual pattern of growth.In addition, this tumour was associated with persistently low spinal fluid glucose levels, a finding which is usually associated with leptomeningeal involvement by an infectious process or a rapidly growing neoplasm. CASE REPORTCLINICAL HISTORY This was a 61-year-old former policeman who was admitted to the Seattle Veterans' Administration Hospital on 18 October, 1963.Since late July 1963, the patient's family had noticed increasing confusion, disorientation, and hallucinations.During the week preceding his admission, they had noted that the patient's right eye was 'turning out', and his admission was precipitated by headache and increasing somnolence.