I've became aware of it about 15 years ago, so it would probably have already killed me if it was anything like that.
In their case the doctors didn't remove it because the operation would have been more dangerous than the tumor itself, and the symptoms were not too severe. But it's obviously better to be aware of such things.
ElongatedTowel ought to go to the doctor and deal with a few weeks of feeling like an embarrassed jerk by demanding that they scan his/her brain.