It finally happened! As the Vet said, Ivy's hystiocytoma would ulcerate, it did and it was disgusting, then it dried up, also disgusting, then it was hanging off her eyelid, TOTALLY DISGUSTING, but I was able to get it to fall off using warm water and compresses. So now she is left with a white patch and I'm wondering if it will go back to it's original skin color and no longer be visible. I certainly hope she does not get another one!!