Extrarenal pelvis

Horseshoe kidney, also known as ren arcuatus (in Latin), renal fusion or super kidney, is a congenital disorder affecting about 1 in 500 people that is more common in men, often asymptomatic, and usually diagnosed incidentally. In this disorder, the patient's kidneys fuse together to form a horseshoe-shape during development in the womb. [Source: Wikipedia ]