Primary tumors originating from cells of the glial lineage usually affect predominantly the white matter of the brain. Only rarely do gliomas destroy the surrounding bone by invasion of the extracellular matrix, especially without prior surgery. This paper describes the unusual case of a 66-year-old female patient with a left-sided intra- and extracranial tumor involving the temporal lobe, destroying the underlying skull base, and growing into the paranasal sinuses, orbit, and temporal bone. Biopsy revealed glioblastoma multiforme with strong GFAP positivity. Molecular biologic investigations of the p53, EGFR, and mdm2 genes showed functional inactivation of the p53 gene but no overexpression of oncogenes. Because the tumor was considered inoperable, palliative irradiation was carried out. The patient died 7 months after diagnosis. The causes of this phenomenon are discussed and the literature reviewed.