I’m a late onset stutterer as well. Mine came on at the end of a battle with alcoholism, and has stuck around ever since. Sometimes it completely clears up, but it’s usually there at least a little bit. Also should add I’m late diagnosed autistic as well. Haven’t gotten many answers from doctors, but in my own research a LOS is usually caused by brain trauma. Psychogenic stutters do happen though, and I think are more common than most people think. I went to a support meet up once, and met 4 out of 7 people with onset stutters (crazy considering it’s supposed to be so random). Hope you found some answers. I looked up your cyst you brought up, and it kinda looks like it’s in the area of the brain that affects speech?