Well, I never had a barium test, but I ended up in the hospital when they found an "unexplainable amount of free floating fluid" in my lower right abdomen on an ultrasound. It turned out to be an abscess. I stayed in the hospital for 12 days after they ran all sorts of tests on me, drained the abscess, and loaded me up with antibiotics and TPN. I was offcially diagnosed with Crohn's in February of this year.
My first reaction when I heard "baseball-sized mass" was tumor, but an abscess is basically an infected sac of fluid - probably from a tear in my colon. Don't be too worried. It's good that they found it. It's one step closer to a diagnosis and treatment. Try not to let it worry you too much. Keep us posted