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 tumours, 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 characterised 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 characterised by a hypointense lesion with surrounding vasogenic oedema causing marked mass effect. There is intense irregular, heterogenous enhancement of the tumour margins with a hypointense center, representing necrosis 3,4.
MR imaging is crucial in tumour characterisation. 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 oedema 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