Not a trick of the eyes. This brain with a pronounced green discoloration belonged to an adult with marked jaundice due to acute and severe liver disease. Jaundice occurs when the blood carries higher than normal levels of bilirubin, a substance that is usually processed by the liver into bile which is then eliminated via the stool and urine. Liver disease may impair bilirubin processing, leading to its buildup in the blood and then deposition in various tissues. Bilirubin deposition in the adult CNS, especially the gray matter and dura, causes a green discoloration, whereas deposition in the skin and sclera (i.e. the white part of the eye) causes a yellow discoloration. Of note, bilirubin deposition in the brain of a newborn causes severe neural damage and a yellow discoloration of brain tissues in a process called kernicterus.
For further study on this topic and others related to neuropathology and neuroanatomy, the following books come highly recommended, and a small portion of the proceeds (or any Amazon purchase through these links) help with expenses of hosting this site: