Thanks for your response. I checked out the link you gave-- unfortunately that is all about an open lesion in the mouth. The lesion on the floor of my mouth only showed up on CT scan. There is no change in the mucosa over it-- I had no idea it was even there until the CT scan. Now that I know it is there I can palpate it with my finger-- it is painless, very hard and feels attached to the jawbone and is towards the back of the floor of the mouth. The fact that there is an enlarged jugular lymph node on the same side as the mouth lesion raises a red flag. My sister, who is a nurse anesthetist, spoke with several higly respectable general surgeons that she works with yesterday. They are the ones that told her that growths like this on the floor of the mout are nearly always cancerous.