Mets or GBM? Why?
GBM almost certainly. A) the three lesions are in a line, along crossing white matter tracts B) the middle lesion is within the corpus callosum, a very unusual location for a metastasis.
Three peripherally enhancing lesions extend in a row from right to left, with the central lesion within the corpus callosum. They are embedded in a continuous region of high T2 signal. The enhancing component demonstrates diffusion restriction similar to normal white matter (~700 x 10-6 mm2/sec). The right sided lesion has evidence of haemorrhage on gradient echo.