Sylvia - you should definitely ask your urologist to interpret this with certainty, but for what it is worth, it sounds like your tumor was 4 millimeters by 4 millimeters by 3 millimeters in size; by contrast, mine was 17 X 14 X 11, much larger by volume. The report suggests that they can't rule out invasion of the lamina propria which is the layer of the bladder right below the epithelia cells; invasion of the lamina propria would stage your cancer as T1, no invasion means superficial Ta. The fact that there was no muscle tissue present indicates that the urologist did not "dig deep enough" to get any; that is what happened to me as well on my first TURBT. Second TURBT he "dug deeper" and got muscle tissue so that the pathologist could look for evidence of cancer cells in that tissue - which would make the staging T2.
Bottom line is that as Sara Anne said, BCG is exactly the right treatment here since you have CIS and high grade. Needless to say, best of luck to you; I also start BCG next week, we can compare notes.