[Congenital megacalycosis].

A case of megacalycosis is described in a newborn with multiple anomalies and enlarged kidneys. Uroradiological studies, TAC, ultrasound and nuclear medicine studies were practiced. The excretory urogram was by far the best technique to demonstrate this entity characterized by enlarged kidneys and uniform dilatation of all the calyces with the remainder of the collecting system normal. Voiding cystourethrography was normal as were renal function tests. This rare urological entity is a form of renal dysplasia which must not be confused with obstructive o refluxing hydronephrosis so that needless surgery is avoided.