Horseshoe kidney. [Genitourinary] [CT]

CT obtained for some unrelated symptoms with an incidental finding.

Near the top, the two kidneys looked normal* [top image]. Near the bottom, the two kidneys wanted to join up into one kidney [bottom image].

*Technically, a little bit of renal malrotation due to the abnormal positioning from the horseshoe morphology.

This is generally a benign finding, but the abnormal shape might contribute to poor urinary drainage, which can cause renal stones, urinary infection, increased risk for cancer from the chronic inflammation caused by repeated infections, or increased risk of injury from trauma.