In the fetus, renal lobes (consisting of a pyramid of collecting tubles and overlying cortex) are separate, eventually fusing to form the typical reniform shape with a smooth surface.  These lobes can persist to produce a lobulated cortical surface, each representing a pyramid and overlying cortex with a valley in between as compared to renal scarring due to vesico-ureteric reflux, where there are cortical defects overlying the pyramids especailly at the upper and lower poles.