Renal hilar lip

A renal hilar lip is a developmental anomaly of the kidney. It is an infolding of the cortex at the level of the renal sinus and in this region the renal cortex appears thicker. 

Radiographic appearance

On imaging it appears as supra- or infra-hilar cortical bulges. At certain levels of cross-sectional imaging this lip may appear to be entirely separate from the kidney and mimics a mass lesion, thus it is considered as one of the renal pseudotumours.

On contrast-enhanced cross-sectional imaging, a similar enhancement pattern as the rest of the renal parenchyma may be seen, thereby differentiating it from a tumour.