By "mobile" I'm not sure whether they mean like rolling all around the bladder (which in this case sounds like it would be a blood clot, not a stone), or an actual soft tissue mass that is swinging in the breeze but attached to the wall by a stalk.MDTs are used for anything complicated or unusual, not just for cancer.
Mobile means its moving around, which is a good sign in general (means its probably not growing from your bladder). The most likely culprit in these scenarios is a bladder stone. The fact that its nonshadowing makes it unusual because most bladder stones have calcifications that shadow. In any case one has to go in with a camera to take a look at it and do something with it.