[Leptomeningeal gliomatosis. 2 clinicopathological cases]

Leptomeningeal gliomatosis is a diffuse glial infiltration of the subarachnoid space. It is primary and very rare when primary astrocytoma arises in the leptomeninges from heterotopic neuroglial tissue; it is secondary and more frequently reported when associated with a medullar or cerebral intraparenchymal astrocytoma and secondary involvement of the leptomeninges. Primary and secondary forms are difficult to differentiate before neuropathological examination. The authors report 2 anatomo-clinical cases of leptomeningeal gliomatosis in adults, with clinical courses of 6 months and 40 days respectively. The initial clinical picture was aseptic chronic or subacute meningitis. Cytologic examinations of the cerebrospinal fluid (CSF) showed moderate lymphocytosis, with elevated protein and low glucose levels, without abnormal cells. On case 2 CT scan and in case 1 spinal MRI isolated diffuse meningeal contrast enhancement was present, without intraparenchymal lesion. The neuropathological study revealed a diffuse astrocytoma glial leptomeningeal tumour with a focal involvement of the central nervous system (spinal cord in one case, temporal lobe in the other). In conclusion, an isolated aseptic lymphocytosis meningitis with meningeal abnormal signal may reveal leptomeningeal gliomatosis. Neuropathological examination can distinguish primary from secondary forms.