The coexistence of congenital megacalyces and primary megaureter.

Congenital megacalyces is a rare developmental condition of the kidney consisting of hypoplasia of the medullary pyramids and dilatation of the calyces. There is no obstruction. Primary megaureter is a form of obstructive uropathy in which there is an obstructing juxtavesical segment of ureter that is normal in caliber but that is aperistaltic. These conditions were found to occur simultaneously in the same patient six times during the past 10 years. Recognition of this rare coexistence is important so that unnecessary surgery can be avoided.