There a round, enhancing mass in the anterior dome of the bladder, which appears associated with the urachus. On the non-contrast images, a small non-obstructive calyceal stone is incidentally noted in the right kidney.
It is quite easy to overlook this subtle finding on axial images, but much more obvious on sagittal reformats. This patient likely had an urachal diverticulum and not a fully patent urachus, as the remainder of the obliterated urachus looks normal on sagittal images. It is essential to look at the bladder in all three planes when working up haematuria, as subtle mass may only be well appreciated in a single plane.
Finally, it is worth noting that the mass is also visible on the non-contrast images. Often when using narrow window/level settings, a subtle (or not-so-subtle) bladder mass may be visible on a more commonly performed non-contrast "renal stone protocol" CT when a patient is being worked up for haematuria, potentially diagnosing the disease at an even earlier time. Careful evaluation of the bladder is essential, even on non-contrast CT's, particularly in higher-risk patients.