If it was a primary tumor, it would usually be a single lesion. Hence, it is concluded to be a melanoma. This specimen has enlarged ventricles and the cortical mantle is thin. There is atrophy or loss of tissue in the cortex and the sulci are widened. If it were normal pressure hydrocephalus, there wouldn't be atrophy.
Any disease affecting the caudate affects the putamen as well due to the close proximity.
Because of the loss of the caudate, the shape of the ventricles becomes broader at the bottom. In this specimen, you find lesions in the white matter due to the destruction of the myelin. These lesions are called glial scars which are flame-shaped lesions. The scar is sharply delineated and typically has a periventricular distribution or is right under the pia. It is also found in the spinal cord on the surface.