Glioblastoma (GBM) is the most common and aggressive primary malignant brain tumor. Despite the current standard of care therapy, including maximal surgical resection, chemoradiation, and tumor-treating fields, prognosis remains poor. Therapeutic failure is driven by an immunosuppressive tumor microenvironment, poor drug penetration across the blood–brain barrier, and robust resistance mechanisms. Epigenetic alterations further compound treatment resistance by enhancing DNA repair and promoting survival pathways. Molecular profiling has identified key prognostic and predictive biomarkers. Gene expression analyses have delineated GBM subtypes, each with distinct molecular features and therapeutic vulnerabilities that hinder successful clinical translation. This review integrates the pathophysiological, diagnostic, and therapeutic landscape of GBM to inform of future strategies for improved patient outcomes.

Background/Objectives: Neurofibromatosis Type 1 (NF1) plexiform neurofibroma (PN) can cause morbidity, including disfigurement that can negatively impact social functioning. Historically, the mainstay treatment is surgical resection. However, complete resection is often prohibitive due to multiple nerve involvement. Moreover, post-operative recurrence is common. MEK inhibitors, including selumetinib and mirdametinib, have recently changed the treatment paradigm for these tumors. In 2020, selumetinib was FDA-approved for pediatric NF1 patients with inoperable symptomatic PNs, but selumetinib remains under investigation for their adult counterparts. In 2025, mirdametinib was FDA-approved for use in adults with symptomatic incompletely resectable NF1 PNs. Lower partial response rates have been reported with mirdametinib compared to selumetinib, but direct comparative analyses have not been conducted to establish the superiority of one agent over the other. Results: We present a case of a 38-year-old male with a right facial PN successfully treated with selumetinib, resulting in a 16.77% tumor volumetric reduction over 7 months. Selumetinib was well tolerated in our patient, with an asymptomatic Grade 3 CPK elevation that subsequently improved with a dose reduction. Conclusion: Our case adds to the growing body of evidence suggesting that selumetinib is effective and well tolerated in adult patients with NF1-associated PNs.