My inital ulcer removal from the tongue wasn't expected to be cancerous. My oral surgeon joked I'd be the first hypnosis candidate to stop biting my tongue before finding out.
Once we found out it was cancer, I saw a zillion different doctors in Boston (arguably the medical meca of the world) and had a zillion tests. The physicals they gave me, the blood tests they gave me, the 3 MRI's they gave me, and the CT they gave me all came back negative for additional cancer. Since my initial excision didn't produce clean margins, the Dana Farber doctors wanted to go back in "just in case". They found another portion of the tumor - nearly 1 cm in diameter in my tongue.
My advice: GO TO DIFFERENT DOCTORS UNTIL THEY DIAGNOSE YOU PROPERLY. There's no way every doctor knows everything about every problem or disease. You are your only advocate in those offices. Demand attention, tests, and whatever it takes. Most of us aren't used to being rude and demanding; we feel as though "doctor knows best" and accept their explanations. They've gone through med-school and training - they'll have thick skin for your demands and second-guesses. If they don't, find someone else!
Go gettum!
Sabrina