Upper urinary tract anomalies and perinatal renal tumors.

Congenital anomalies of the upper urinary tract are common and frequently diagnosed on prenatal ultrasound. In the absence of infection, these anomalies are often asymptomatic. This article reviews key features and long-term implications to assist in discussions with families. In contrast, a perinatal renal tumor is rare but extremely alarming. This update on the most common tumors and their treatment is useful in reassuring parents that most infants, after primary surgical resection, are cured without adjuvant therapies. To understand renal agenesis and other congenital renal malformations and their associated anomalies, a brief review of normal renal development is presented.