Posterior urethral valves as a cause of neonatal uriniferous perirenal pseudocyst (urinoma).

Two neonates with uriniferous perirenal pseudocysts (urinomas) secondary to posterior urethral valves are presented. Early diagnosis was achieved and both patients survived. The characteristic roentgenographic appearance of the pseudocyst is described. An investigation for lower urinary tract obstruction should always be undertaken when pseudocyst or ascites is seen in the neonate. Prompt diagnosis and treatment is essential to avoid irreversible renal damage, electrolyte or fluid imbalance, or respiratory compromise.