GLIOMATOSIS CEREBRI - DISCONNECTION OF THE CORTICAL GREY-MATTER, DEMONSTRATED ON PET SCAN

18-FDG and 11C methionine PET scans were performed on two patients wit h gliomatosis cerebri. The cortical grey matter was hypometabolic when compared with normal. The findings support the concept that: the cere bral cortex becomes functionally disconnected in this disease owing to the infiltrative nature of the underlying tumour. This may account fo r the high incidence of dementia in the course of this disease. In one of the cases described here, there was clear evidence of progression from a discrete tumour mass of glioma to gliomatosis cerebri and this progression argues against the WHO classification of this disorder sep arately from glioma.