Neuro-oncology beyond the usual: cerebral glioma in the occipital region." Case report.

Abstract

Gliomas are the most complex primary tumors of the central nervous system (CNS). Glioblastoma (GBM) is the most common malignant glioma in adults, generally affecting the frontal and temporal lobes. Its primary location in the occipital lobe (<3% of supratentorial cases) represents an unusual anatomical location with a particular diagnostic challenge. We present a case of right occipital GBM that highlights this rarity. Case report: A 60-year-old male patient presented with visual symptoms: phosphenes and left homonymous hemianopsia, followed by hallucinations and abrupt progression to a generalized tonic-clonic seizure. Neuroimaging studies (CT and MRI) revealed an intra-axial space-occupying lesion (SOL) with enhancement in the right occipital region, surrounded by significant vasogenic edema. An emergency craniotomy with partial excision was performed. Histopathological analysis confirmed a grade 4 diffuse glioma suggestive of glioblastoma, and the immunohistochemical profile showed positivity for EGFR and negativity for MGMT methylation, although the partial presence of IDH-mutated cells suggested the need to rule out oligodendroglioma. Conclusion: This clinical case highlights the unusual location in the occipital lobe and its consequent clinical presentation, where visual symptoms (phosphenes and hemianopsia) were the initial manifestation. The rapid progression to seizures underscores the aggressiveness of GBM. It is crucial to maintain a high index of suspicion for visual symptoms in older adults, as early surgical intervention and complete molecular diagnosis are vital for the prognosis of these rare neoplasms.