Strange as it sounds, there are a couple cases on record of pedophilia directly caused by a brain tumor.
The subject of pedophilia is one of the most emotionally charged issues in society, and for good reason. The idea that something so vile can be caused by a physical disease–in this case, a tumor–blurs the line between morality and biology.
This story involves a previously healthy schoolteacher who suddenly developed a number of compulsive tendencies, one being sexual desire for children. He also began soliciting prostitutes and having fantasies of raping his landlady. He was kicked out of a 12-step Sexaholics Anonymous program after propositioning a female patient for sex.
Despite knowing intellectually that his behaviors were wrong, he claims that the desire over-rode his morality. After developing paralyzing headaches and balance problems, he underwent an MRI. Lo and behold, an egg-sized tumor was found in the orbitofrontal cortex of his brain–the area that controls judgment and impulse control. The tumor was successfully removed and he was discharged, apparently free of his dark impulses.
And here’s where things get strange.
Seven months later the inappropriate urges returned, along with the headaches. The tumor had regrown and was removed once more, taking the pedophilic impulses away with it.
Personality changes are a common side effect of brain tumors, but this is an extreme case. Whether the urges are caused by hormonal changes or disturbances within the orbitofrontal cortex is not entirely clear. Unlocking these mysteries could give researchers insight into pedophilia and other impulse-driven deviant behaviors.
Here is another case similar to the one above.