Transverse folds of the adult obstructed ureter. Case report

Transverse folds in the distal ureter were found on urograms in two adult patients with ureteral obstruction. These folds were associated with but did not cause ureteral obstruction. Histopathological examination of the excised ureter in one patient showed that the folds were made of luminal projections of lamina propria containing prominent bundles of smooth muscle. The folds probably originate as a result of a lower compliance of the distal part of the ureter, which reduces the distension produced by a luminal rise in pressure.