Glioblastoma Multiforme Occurring After 20 Years at the Resection Site of Cerebral Arteriovenous Malformation: A Case Report and Literature Review.

Glioblastoma (GBM) arising at the site of a previously resected arteriovenous malformation (AVM) is exceedingly rare, and its pathophysiological significance remains unclear. Here, we present a unique case of GBM diagnosed two decades after AVM resection and review the literature on AVM-associated, high-grade gliomas. A 67-year-old male presented with headaches and right-sided hemiparesis of progressive onset. Brain MRI revealed a 6 × 4.5 cm heterogeneously enhancing lesion with perifocal edema in the left parietal lobe, precisely where an AVM had been surgically removed 20 years earlier, without adjuvant radiotherapy. The patient underwent gross total resection of the lesion. Histopathological and molecular analysis confirmed GBM, IDH-wild type, with MGMT promoter methylation. To date, nine cases have documented histological coexistence of GBM with AVM or arteriovenous fistula, with one case reporting radiological co-occurrence in distinct brain regions. Additionally, isolated reports describe AVM associated with other high-grade gliomas, including anaplastic variants, either concurrently or sequentially. GBM developing at the site of prior AVM resection is unique, raising questions about a potential biological link. This case underscores the importance of long-term surveillance in AVM patients post-surgery. Further investigation through large-scale cohort studies is warranted to elucidate any mechanistic or oncogenic relationship between AVMs and gliomas, particularly GBM.