Complex sentence: Bladder cancer characteristically causes blood in the urine; this may be visible to the naked eye (gross/macroscopic hematuria) or detectable only by microscope (microscopic hematuria).
Split into simpler sentences: Bladder cancer characteristically causes blood in the urine. This blood in the urine may be visible to the naked eye (gross/macroscopic hematuria) or detectable only by microscope (microscopic hematuria).