Which condition refers to a duplication of the renal collecting system?

The condition that refers to a duplication of the renal collecting system is known as a duplex kidney. This anatomical variation occurs when there are two ureters draining a single kidney, which can arise from a complete or partial duplication of the renal collecting system.

The duplex kidney may present with varying degrees of duplication, and it can be found in one or both kidneys. This duplication can lead to complications such as urinary tract infections or hydronephrosis if the additional ureter is obstructed. The identification of a duplex kidney is crucial, as it can influence surgical management in cases of associated pathologies.

Conditions such as posterior urethral valves and multicystic dysplastic kidney have different pathophysiological mechanisms and presentations. Posterior urethral valves are associated with bladder outlet obstruction in male infants, while multicystic dysplastic kidney involves multiple cysts within the kidney due to abnormal development and does not involve duplication. Angiomyolipoma is a benign tumor composed of blood vessels, smooth muscle, and fat that can occur in the kidney but is unrelated to the duplication of the collecting system. Therefore, the correct identification of a duplex kidney is significant in the understanding of renal anatomy and potential clinical implications.