Glioblastoma mimicking autoimmune meningitis in an adult: A complex diagnostic challenge.

Background: Glioblastoma multiforme (GBM) is a highly aggressive primary brain tumor with a poor prognosis. It commonly affects the brain and rarely spreads outside the central nervous system owing to barriers like the blood-brain barrier. We present a rare case of GBM with atypical features mimicking autoimmune meningitis, complicating the diagnosis. Case Description: A 45-year-old previously healthy man presented with persistent headaches, dizziness, vomiting, neck pain, diplopia from bilateral abducens nerve palsy, and cognitive dysfunction. The cerebrospinal fluid analysis did not confirm meningitis, although initial clinical and radiological findings suggested autoimmune meningitis. Head magnetic resonance imaging (MRI) showed postcontrast leptomeningeal enhancement and meningeal thickening. A spinal MRI revealed a contrast-enhancing lesion at the L1 level with leptomeningeal enhancement of the spinal cord. Despite empirical steroid therapy, his condition worsened, resulting in severe neurological deficits and impaired consciousness. A biopsy confirmed GBM through L1-2 laminectomy. Although adjuvant therapy was scheduled, his health rapidly declined, and he passed away on the 24 Conclusion: GBM can rarely present with noticeable symptoms and radiological features resembling autoimmune meningitis, posing diagnostic challenges. GBM cases involving spinal dissemination typically have a poorer prognosis, emphasizing the necessity of thorough diagnostic strategies. These should encompass histopathological biopsy and advanced imaging for optimal management, as delayed intervention significantly impacts survival. This report highlights the importance of maintaining a high level of suspicion for GBM and prompt intervention, including biopsy, in the presence of atypical clinical, radiological, and laboratory signs suggestive of meningitis.