What is the differential diagnosis?
In this age group if the lesion is primarily of the choroid plexus, then a metastases would be most likely. If in the adjacent parenchyma then exophytic primary tumour (e.g. GBM) or even a parenchymal metastasis or possibly an ependymoma should be considered.
There is a 23 x 29 x 28 mm lobulated lesion centred either within the left superomedial temporal lobe. Its epicentre is difficult to clearly localise. It may be in the parenchyma of the temporal lobe extending into the posterior external capsule and posterior to the left lentiform nucleus or in the choroid plexus with extraventricular extension. It is partially solid / cystic with vivid enhancement of internal septae. This has local mass effect, with extensive surrounding vasogenic oedema, sulcal effacement, partial effacement of the left ambient cistern and lateral ventricle. The temporal horn of the left lateral ventricle, which is entrapped / dilated. This is a solitary lesion.
Elsewhere non specific deep white matter foci are seen most likely related to small vessel ischaemia.