Organizing and old infarcts: Two areas of infarction are shown in this photograph, which contains a coronal section through the frontal lobes at the level of the third ventricle and mammillary bodies. On the left is a recent (1-2 weeks old) hemorrhagic infarct, characterized by discoloration. On the right side is an old infarct in which the affected tissue has been totally removed by phagocytes, leaving a cavity behind. The margins are irregular, and slight contraction of surrounding tissue has taken place causing dilatation of the adjacent ventricle (hydrocephalus ex vacuo). The orange discoloration represents hemosiderin, indicating that the infarct was hemorrhagic.