If there's any question of UC vs. Crohn's, have them give you a colonoscopy with biopsies before having any surgery. In UC they remove the colon and you're considered cured. With Crohn's they remove as little as possible, because it can, and probably will, come back.
Sometimes it's really hard for the doctors to decide between UC and Crohn's. A lot of us have had our diagnoses changed. I was diagnosed in June of this year, and my doctors have already said Crohn's, no wait- it's UC, oh nevermind Crohn's.