Which radiographic features help to differentiate anaplastic astrocytomas from low-grade gliomas? Which features help to differentiate them from glioblastomas?
Anaplastic astrocytomas share common features with both low-grade diffuse astrocytomas and glioblastomas as they are an intermediate tumour between them. Low-grade tumours usually do not enhance after contrast administration (unless gemistocytic or other variants, that can demonstrate enhancement). Glioblastomas often show central non-enhancing fluid-intensity regions (necrosis).
Brain MRI demonstrates a right thalamic-centred lesion that also extends to the right hippocampus and tectum. It has a low T1 signal and a heterogeneous high T2 signal. It results in mild compression of the adjacent the right lateral ventricle. There is no midline shift. The remainder brain is unremarkable.
Contrast was not administered due to allergy.