Morphological aspects of the epithelium of the trigone of the human urinary bladder: immunohistochemical findings and histogenetic features.

An immunohistochemical method was used to study the structural characteristics of the epithelium of the bladder trigone in 20 premenopausal women. Fragments of mucosa were obtained by cystoscopy from the trigones of the 20 subjects. Monoclonal antibodies (34 beta E12 and 34 beta B4) were used to demonstrate the presence of stratified squamous epithelium-specific cytokeratins in these samples. Based on our results, we believe that the frequent finding of stratified squamous epithelium in the trigone of the female bladder is a consequence of the stimulation of estrogen, which is believed to act on the trigone, but not on the rest of the bladder. This may be due to the complex histogenesis of the bladder. Embryologically, the trigone derives from the mesoderm, while the rest of the bladder derives from the endoderm.