Malrotation of the kidney

It is Unilateral or bilateral anomaly. When the renal pelvis is situated in an anterior or lateral position, the upper part of the ureter often appears to be displaced laterally, suggesting an extrinsic mass. The elongated pelvis of a malrotated kidney may mimic obstructive dilatation.

Findings :

Often bizarre appearance of the renal parenchyma, calyces, and pelvis that may suggest a pathologic condition in an otherwise normal kidney.

Malrotation of the left kidney. Note the apparent lateral displacement of the upper ureter and the elongation of the pelvis.