Leptomeningeal gliomatosis.

The diagnosis of leptomeningeal gliomatosis is discussed in relation to a single case studied in detail. Histology showed extensive subarachnoid spread of tumour that seemed to originate in an astrocytoma of the ventricular wall. The spinal fluid was xanthochromic with a high protein content. Reports of primary leptomeningeal gliomatosis are reviewed and the need for detailed histological study of the brain in such cases is emphasised.