Yadira Rostro, of Garland, Texas, suffered terrible headaches for nine months- until a scan revealed that parasitic tapeworms were growing at the base of her brain. Doctors removed a piece of her skull and took eight larval sacs from her brain.

Source: Ripley's Believe it or not

My information:
Tapeworms in the brain may be uncommon, but still deadly. This happens when an animal or human eats either infected meat or dirt containing tape worm eggs. What happens is that the worms enter the bloodstream and can end up in the brain. In 2007 an infant was killed after consuming tapeworm eggs and the worms destroyed the child's brain.