Uriniferous perirenal pseudocyst in a neonate with primary obstructive megaureter

The case of a newborn infant with a high-grade ureterovesical junction obstruction--a primary obstructive megaureter--who presented with a perirenal pseudocyst (urinoma) is discussed. Radionuclide studies allowed recognition of this collection and led to the discovery of the ureteral obstruction. The rarity of urinomas in neonates and the scintigraphic appearance of urinomas are emphasized.