Urinary tract malignancies of infancy and young childhood

The function of the urinary tract is to filter the blood of impurities, produce and eliminate urine from the body, and maintain electrolyte homeostasis. The urinary tract consists of two kidneys that lie retroperitoneally in the abdomen, each drained by a ureter that empties into the bladder that collects and stores urine before expelling urine through the urethra. Disorders of the development of the urinary tract, such as anatomic renal anomalies or posterior urethral valves or faulty implantation of the ureters to the bladder, are relatively much more common than malignancies of the urinary tract; however, cancers of the urinary system do sometimes present in infancy and may arise from any urinary tract structure. In this review, we will describe various malignancies that involve the urinary tract of infants, consider them in the greater context of childhood malignancies, discuss various genetic syndromes that predispose to such cancers, and outline some of the challenges of treating infants and very young children with anticancer therapy.