Glioblastoma, IDH-wildtype, with spontaneous transdural and calvarial invasion: a case report and literature review.

Glioblastoma (GBM), IDH-wildtype, is the most aggressive adult-type diffuse glioma. Although extracranial spread may occur after craniotomy, radiotherapy, or other interventions, spontaneous transdural and calvarial invasion before treatment is exceedingly rare. We report a 37-year-old woman who presented with long-standing right temporal-parietal headache and acute worsening with vomiting. Computed tomography and magnetic resonance imaging demonstrated a right temporal mass with intratumoral hemorrhage, peritumoral edema, and contiguous extension through the dura and temporal bone into the temporalis muscle. The lesion was resected through a transcranial approach, and postoperative imaging showed gross total resection. Histological examination demonstrated an infiltrating high-grade glial neoplasm with brisk mitotic activity and palisading necrosis. Immunohistochemical and molecular findings, including the absence of IDH1/IDH2 mutations, supported a diagnosis of glioblastoma, IDH-wildtype, CNS WHO grade 4. At 18 months after surgery, the patient remained alive. This case highlights a rare pattern of primary extracranial extension in GBM and suggests direct contiguous transdural invasion as a plausible route of spread in the absence of prior intervention.