Glioblastoma multiforme (GBM), or glioblastoma, is the most common primary brain malignancy accounting for 15-20% of all intracranial neoplasms ¹. They are subdivided into astrocytomas and oligodendrogliomas, with the former being the most common type of glioma ². It is one of the most biologically aggressive tumors, and despite management options of surgical resection, radiation therapy, chemotherapy, over 75% of patients die within 18 months ³.

GBMs arise in white matter, infiltrate along white matter tracts and perivascular spaces, and are characterized by a solitary and large irregularly shaped mass with associated necrosis and neovascularity ⁴. Typical histopathological features include cellular polymorphism, increased mitotic activity, atypical nuclei, vascular thrombosis and microvascular proliferation as well as necrosis ⁵.

Imaging is an integral component for clinical diagnosis, evaluation, treatment planning, and assessing the response to treatment/therapy. On CT imaging, GBMs are characterized by a hypointense lesion with surrounding vasogenic edema causing marked mass effect. There is intense irregular, heterogenous enhancement of the tumor margins with a hypointense center, representing necrosis ^3,4.

MR imaging is crucial in tumor characterization. Lesions are typically hypo-intense on T1 weighted images and hyperintense on T2 weighted images and FLAIR ^3,4. With intravenous contrast administration, findings include irregular and nodular rim enhancement with central hypo-intensity (interpreted as necrosis), Ill-defined margins and extensive surrounding hyperintensity corresponding to edema ⁶. Metabolic information may be acquired using MR spectroscopy where there is typically a reduction in NAA (N-acetylaspartate) corresponding to a decreased density of neuronal cells and increased choline as a result of higher cell membrane turnover ⁴.

Case courtesy of Associated Professor Pramit Phal