The MRI features in a patient known for breast carcinoma are highly suggestive of brain metastases. The symmetrical location in the capsulo-lenticular regions is rarely seen (as in this case).
CNS lymphoma may be considered in the differential diagnosis, however some MRI findings are against this diagnosis:
the location of the frontal and temporal lesions at the grey-white matter junction
the surrounding oedema is usually more prominent in metastases compared to CNS lymphoma
the MR spectroscopy in this case is almost typical of metastases, while in CNS lymphoma, we usually observe a reversed choline/creatinine peak +/- sometimes a lactate peak