RESUMEN
Glioblastoma multiforme (GBM) is a high grade glial tumor, primarily located in cerebral hemispheres. The most common clinical presentations are slowly progressive neurological deficit such as motor weakness, seizure, and headaches that last less than three months. Calvarium and extra-axial invasion are very rare and generally occur after a brain biopsy or surgery, or secondary to radiotherapy of primary intra-axial glial tumors. We report a case of GBM with calvarium involvement in a 60-year-old man who presented with a frontal bump and left-sided clumsiness. Imaging studies revealed a tumoral lesion that destroyed the frontal bone with white matter involvement of the frontal lobe and extension into the corpus callosum. Histopathological examination of intra-axial and extra-axial lesions revealed pleomorphic high-grade tumor with large areas of necrosis and hemorrhage. Immunohistochemical (IHC) studies confirmed GBM that spread directly into the dura, galea, and calvarium (positive reaction for GFAP, S-100, CD68, OLIG2, and p53). The patient was treated with radiotherapy (60Gy/30 fractions) and concomitant temozolomide. Unfortunately, the patient died seven months after the initial diagnosis.