Ultrastructural characteristics of collagen tissue in normal and congenitally dilated ureter.

Scanning electron microscopy is a useful method to study the organization distribution and orientation of the collagen fibers in the ureteral wall. Different collagen structural patterns have been observed in normal ureter, primary obstructive megaureter and refluxing megaureter. A pathogenic hypothesis is advanced based on the different functional characteristics of each one of these entities. Collagenous proliferation in primary obstructive megaureter and refluxing megaureter could be related to ureteric smooth muscle cell disfunction.