This adult patient shows a ballooning of the pelvis (P) of the left kidney (see ultrasound images above). A major portion of the renal pelvis lies outside the renal sinus, a condition called extrarenal pelvis. The transverse section image (lower image), brings out the lesion clearly. The extrarenal pelvis is a normal variant and needs no specific treatment. However, in this case, the calyces of the left kidney show mild ballooning suggesting obstructive changes which require further radiological study.