A peripherally enhancing mass at the grey-white matter junction of the supramarginal gyrus with significant surrounding oedema. Central diffusion restriction is likely secondary to blood products admixed with proteinacous necrotic material.
Conclusion: The differential is primarily that of a haemorrhagic metastasis (e.g. melanoma). A cavernoma would not be expected to have this degree of enhancement or diffusion restriction. An abscess is possible but the degree of signal loss is more consistent with blood than the thin low T2 rim seen in abscesses.