There is a diffuse irregular predominantly subcortical hypodensity within the inferior aspect of the left frontal lobe, although there is cortical involvement at the left frontal pole. This hypodensity involves the anterior aspect of the corpus callosum as well the genu, with resultant expansion of the corpus callosum. The abnormal hypodensity also extends via the corpus callosum into the deep white matter of the right frontal lobe. This corresponds to the intra-axial heterogeneous T1 signal, predominantly T2 hyperintense with partial FLAIR suppression, and at best wispy contrast enhancing intra-axial mass identified on the previous external MRI (not shown on this case). Within the inferior left frontal component, there are scattered foci of peripheral calcification. No acute haemorrhage within the mass. There is also significant surrounding white matter hypodensity, that extends posteriorly along bilateral external capsules, greater on the left. This mass causes almost complete effacement of the frontal horns of the lateral ventricles bilaterally. No hydrocephalus. No midline shift. No bony destruction of the floor of the anterior cranial fossa. No suspicious bony lesion.
IMPRESSION: Large intra axial mass with cortical involvement, centred within the inferior left frontal lobe with expansion of the anterior corpus callosum and extension across the midline into the right frontal lobe demonstrates speckled foci of peripheral calcification. When compared to the external MRI, the findings are almost certainly those of a primary brain tumour. Morphology and presence of calcification are suggestive of an oligodendroglioma or more likely an oligoastrocytoma, with either protoplasmic or gemistocytic astrocytic component (WHO II or III).