MRI
A peripherally enhancing left basal ganglia lesion with blood product and central restricted diffusion is present surrounded by vasogenic oedema. Inferolaterally a larger cystic component with thin peripheral enhancement demonstrates high T2 signal consistent with fluid and facilitated diffusion, with no hint of abnormally low diffusion restriction. MR spectroscopy demonstrates some elevation of choline lateral to the lesion with a very prominent lipid lactate peaks centrally. MR perfusion demonstrates elevation of cerebral blood volume in the enhancing components.
Conclusion: Left basal ganglia lesion most likely represents a glioblastoma. A necrotic/ haemorrhaging metastasis is though less likely, and if so it wouldn't be from prostate carcinoma but some other primary (e.g. melanoma or lung). Despite the presence of diffusion restriction within one component of the lesion, the minimal change over 2 weeks (prior MRI not shown), and presence of a blood product that can account for this appearance, makes this very unlikely to represent infection.