Extensive subdural spread of a glioblastoma associated with subdural hygroma: case report.

Despite its highly malignant behaviour, glioblastoma very rarely spread beside the arachnoid layer. We describe a very rare case of a 67-year-old patient with glioblastoma, who developed a recurrent subdural hygroma associated with the subdural spread of the glioblastoma, which was confirmed histologically. Possible predisposing factors and management suggestions are discussed.