Has the MRI brain helped in narrowing the differentials?
Yes, an abscess could be excluded (small peripheral areas of restricted diffusion related to a septated cystic component are likely related to the tumoural component rather than due to infection). Differentials are made between metastasis and high-grade glioma.
Large left frontal lobe multilobulated cystic lesion showing an internal high T2 signal that partially suppresses on FLAIR and has thin enhancing margins. There is a small posterior septated lobulation that has restricted diffusion but that otherwise has the same signal pattern of the core lesion; other small foci of diffusion restriction are noted within the enhancing rim at the medial margins of the lesion. The tumour causes a noticeable mass effect with surrounding vasogenic oedema, subfalcine herniation and rightward midline shift in about 2 cm. No uncal or tonsillar herniation. Areas of elevated cerebral blood volume (CBV) at parts of the margin. The cortex appears to be spared on the T2 axial images, with no definitive evidence of cortical thickening. No convincing choline elevation along the lesion margins on spectroscopy. Although these findings suggest metastasis, presence of increased T2/FLAIR signal involving the genu of the corpus callosum would be more in keeping with glioma. Right frontal lobe area of encephalomalacia is probably sequela of a previous infarct.