| This refers to those cases in which the urothelium changes to
squamous epithelium [74].
It may be keratinizing (Fig. 1) or non-keratinizing [16,69].
Squamous epithelium similar to that of vaginal mucosa is normally found
in the trigone and bladder neck particularly in women and should not be
regarded as metaplasia (Fig. 2) [30].
Metaplastic squamous epithelium is commonly seen in a setting of chronic
irritation such as stones, diverticula, nonfunctioning bladders, or schistosomiasis.
Keratinizing squamous metaplasia (leukoplakia) constitutes a significant
risk factor for the development of carcinoma, and most squamous cell carcinomas
of the bladder arise from areas of keratinizing squamous metaplasia. |
