Figure 1.

Stricture pathogenesis. The pathological changes associated with strictures show that the normal pseudostratified columnar epithelium is replaced with squamous metaplasia. a | Small tears in this metaplastic tissue result in urinary extravasation, which causes a fibrotic reaction of the spongiosum. At the time of injury, this fibrosis can be asymptomatic, but the fibrotic process might cause b | further narrowing of the lumen of the urethra in the future, potentially resulting in c | spongiofibrosis d | and extra-spongiofibrosis, as well as symptomatic obstructive voiding symptoms.