Glioblastoma eroding through falx cerebri: a rarity or commonly seen? Illustrative case

Glioblastoma, isocitrate dehydrogenase-wildtype CNS WHO grade 4 (formerly primary glioblastoma multiforme), is the most common and most malignant primary brain tumor. High-grade gliomas most commonly present as unifocal lesions; however, they invade the brain parenchyma in a diffuse manner, an attribute that renders successful resection difficult. Resection, wherein resection of more than 90% of the tumor mass must be achieved to improve outcomes, represents the first step in optimal treatment; therefore, surgical planning, approach, and technique are of utmost importance for successful treatment.

In this paper, the authors present a rare case of a glioblastoma presenting as an atypical bilateral lesion with erosion through the falx cerebri. Morphologically, it was overtly distinct from a typical butterfly glioma. Initially, the authors believed this tumor to be a meningioma, or even a sarcoma, based on radiological morphology. Intraoperatively, destruction of the falx cerebri by the tumor, with spread to the contralateral hemisphere, was seen.

To the best of the authors' knowledge, the erosion of the falx cerebri has not been previously described in glioblastoma in the literature, and this case highlights the importance of a thorough differential diagnosis and understanding its impact on surgical planning. https://thejns.org/doi/10.3171/CASE25410.